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1 {{box title="**Содержание**"}}
2 {{toc/}}
3 {{/box}}
4
5 **Revision History**
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7 (% style="width:954.835px" %)
8 |(% style="width:106px" %)**Revision**|(% style="width:124px" %)**Date**|(% style="width:723px" %)**Contents**
9 |(% style="width:106px" %) |(% style="width:124px" %)April 2011|(% style="width:723px" %)Initial release
10 |(% style="width:106px" %)1.0|(% style="width:124px" %)April 2013|(% style="width:723px" %)Added section 9 - Transforming between versions of SDMX
11 |(% style="width:106px" %)2.0|(% style="width:124px" %)July 2020|(% style="width:723px" %)Added section 10 – Validation and Transformation Language – before the Annex 1.
12
13 = 1 Purpose and Structure =
14
15 == 1.1 Purpose ==
16
17 The intention of this document is to document certain aspects of [[SDMX>>doc:sdmx:Glossary.Statistical data and metadata exchange.WebHome]] that are important to understand and will aid implementation decisions. The explanations here supplement the information documented in the [[SDMX>>doc:sdmx:Glossary.Statistical data and metadata exchange.WebHome]] XML schema and the Information Model.
18
19 == 1.2 Structure ==
20
21 This document is organized into the following major parts:
22
23 A guide to the [[SDMX Information Model>>doc:sdmx:Glossary.SDMX Information Model.WebHome]] relating to [[Data Structure Definitions>>doc:sdmx:Glossary.Data structure definition.WebHome]] and [[Data Sets>>doc:sdmx:Glossary.Data set.WebHome]], statement of differences in functionality supported by the different formats and syntaxes for [[Data Structure Definitions>>doc:sdmx:Glossary.Data structure definition.WebHome]] and [[Data Sets>>doc:sdmx:Glossary.Data set.WebHome]], and best practices for use of [[SDMX>>doc:sdmx:Glossary.Statistical data and metadata exchange.WebHome]] formats, including the [[representation>>doc:sdmx:Glossary.Representation.WebHome]] for time period.
24
25 A guide to the [[SDMX Information Model>>doc:sdmx:Glossary.SDMX Information Model.WebHome]] relating to [[Metadata Structure Definitions>>doc:sdmx:Glossary.Metadata structure definition.WebHome]], and Metadata Sets
26
27 Other structural [[artefacts>>doc:sdmx:Glossary.Artefact.WebHome]] of interest: agencies, (% style="color:#e74c3c" %)concept(%%) role. (% style="color:#e74c3c" %)constraint(%%), partial [[code list>>doc:sdmx:Glossary.Code list.WebHome]]
28
29 = 2 General Notes on This Document =
30
31 At this (% style="color:#e74c3c" %)version(%%) of the standards, the term “Key family” is replaced by [[Data Structure Definition>>doc:sdmx:Glossary.Data structure definition.WebHome]] (also known and referred to as [[DSD>>doc:sdmx:Glossary.Data structure definition.WebHome]]) both in the XML schemas and the Information Model. The term “Key family” is not familiar to many people and its name was taken from the model of [[SDMX-EDI>>doc:sdmx:Glossary.SDMX-EDI.WebHome]] (previously known as GESMES/TS). The more familiar name “[[Data Structure Definition>>doc:sdmx:Glossary.Data structure definition.WebHome]]” which was used in many documents is now also the technical [[artefact>>doc:sdmx:Glossary.Artefact.WebHome]] in the [[SDMX-ML>>doc:sdmx:Glossary.SDMX-ML.WebHome]] and Information Model technical specifications. The term “Key family” is still used in the [[SDMX-EDI>>doc:sdmx:Glossary.SDMX-EDI.WebHome]] specification.
32
33 There has been much work within the [[SDMX>>doc:sdmx:Glossary.Statistical data and metadata exchange.WebHome]] community on the creation of user guides, tutorials, and other aides to implementation and understanding of the standard. This document is not intended to duplicate the function of these documents, but instead represents a short set of technical notes not generally covered elsewhere.
34
35 = 3 Guide for SDMX Format Standards =
36
37 == 3.1 Introduction ==
38
39 This guide exists to provide information to implementers of the [[SDMX>>doc:sdmx:Glossary.Statistical data and metadata exchange.WebHome]] format standards – [[SDMX-ML>>doc:sdmx:Glossary.SDMX-ML.WebHome]] and [[SDMX-EDI>>doc:sdmx:Glossary.SDMX-EDI.WebHome]] – that are concerned with data, i.e. [[Data Structure Definitions>>doc:sdmx:Glossary.Data structure definition.WebHome]] and [[Data Sets>>doc:sdmx:Glossary.Data set.WebHome]]. This section is intended to provide information which will help users of [[SDMX>>doc:sdmx:Glossary.Statistical data and metadata exchange.WebHome]] understand and implement the standards. It is not normative, and it does not provide any rules for the use of the standards, such as those found in //[[SDMX-ML>>doc:sdmx:Glossary.SDMX-ML.WebHome]]: Schema and Documentation// and //[[SDMX-EDI>>doc:sdmx:Glossary.SDMX-EDI.WebHome]]: Syntax and Documentation//.
40
41 == 3.2 SDMX Information Model for Format Implementers ==
42
43 === 3.2.1 Introduction ===
44
45 The purpose of this sub-section is to provide an introduction to the [[SDMX-IM>>doc:sdmx:Glossary.SDMX Information Model.WebHome]] relating to [[Data Structure Definitions>>doc:sdmx:Glossary.Data structure definition.WebHome]] and [[Data Sets>>doc:sdmx:Glossary.Data set.WebHome]] for those whose primary interest is in the use of the XML or EDI formats. For those wishing to have a deeper understanding of the Information Model, the full [[SDMX-IM>>doc:sdmx:Glossary.SDMX Information Model.WebHome]] document, and other sections in this guide provide a more in-depth view, along with UML diagrams and supporting explanation. For those who are unfamiliar with DSDs, an appendix to the [[SDMX-IM>>doc:sdmx:Glossary.SDMX Information Model.WebHome]] provides a tutorial which may serve as a useful introduction.
46
47 The [[SDMX-IM>>doc:sdmx:Glossary.SDMX Information Model.WebHome]] is used to describe the basic data and metadata structures used in all of the [[SDMX>>doc:sdmx:Glossary.Statistical data and metadata exchange.WebHome]] data formats. The Information Model concerns itself with statistical data and its [[structural metadata>>doc:sdmx:Glossary.Structural metadata.WebHome]], and that is what is described here. Both [[structural metadata>>doc:sdmx:Glossary.Structural metadata.WebHome]] and data have some additional metadata in common, related to their management and administration. These aspects of the data model are not addressed in this section and covered elsewhere in this guide or in the full [[SDMX-IM>>doc:sdmx:Glossary.SDMX Information Model.WebHome]] document.
48
49 The [[Data Structure Definition>>doc:sdmx:Glossary.Data structure definition.WebHome]] and [[Data Set>>doc:sdmx:Glossary.Data set.WebHome]] parts of the information model are consistent with the GESMES/TS (% style="color:#e74c3c" %)version(%%) 3.0 Data Model (called [[SDMX-EDI>>doc:sdmx:Glossary.SDMX-EDI.WebHome]] in the [[SDMX>>doc:sdmx:Glossary.Statistical data and metadata exchange.WebHome]] standard), with these exceptions:
50
51 * the “[[sibling group>>doc:sdmx:Glossary.Sibling group.WebHome]]” construct has been generalized to permit any [[dimension>>doc:sdmx:Glossary.Dimension.WebHome]] or [[dimensions>>doc:sdmx:Glossary.Dimension.WebHome]] to be wildcarded, and not just frequency, as in GESMES/TS. It has been renamed a “group” to distinguish it from the “[[sibling group>>doc:sdmx:Glossary.Sibling group.WebHome]]” where only frequency is wildcarded. The set of allowable partial “group” keys must be declared in the [[DSD>>doc:sdmx:Glossary.Data structure definition.WebHome]], and [[attributes>>doc:sdmx:Glossary.Attribute.WebHome]] may be attached to any of these [[group keys>>doc:sdmx:Glossary.Group key.WebHome]];
52 * furthermore, whilst the “group” has been retained for compatibility with (% style="color:#e74c3c" %)version(%%) 2.0 and with [[SDMX-EDI>>doc:sdmx:Glossary.SDMX-EDI.WebHome]], it has, at (% style="color:#e74c3c" %)version(%%) 2.1, been replaced by the “[[Attribute Relationship>>doc:sdmx:Glossary.Attribute relationship.WebHome]]” definition which is explained later
53 * the section on data [[representation>>doc:sdmx:Glossary.Representation.WebHome]] is now a convention, to support interoperability with EDIFACT-syntax implementations ( see section 3.3.2);
54
55 [[DSD>>doc:sdmx:Glossary.Data structure definition.WebHome]]-specific data formats are derived from the model, and some supporting features for declaring multiple [[measures>>doc:sdmx:Glossary.Measure.WebHome]] have been added to the [[structural metadata>>doc:sdmx:Glossary.Structural metadata.WebHome]] descriptions Clearly, this is not a coincidence. The GESMES/TS Data Model provides the foundation for the EDIFACT messages in [[SDMX-EDI>>doc:sdmx:Glossary.SDMX-EDI.WebHome]], and also is the starting point for the development of [[SDMX-ML>>doc:sdmx:Glossary.SDMX-ML.WebHome]].
56
57 Note that in the descriptions below, text in courier and italicised are the names used in the information model (e.g. //[[DataSet>>doc:sdmx:Glossary.Data set.WebHome]]//).
58
59 == 3.3 SDMX-ML and SDMX-EDI: Comparison of Expressive Capabilities and Function ==
60
61 [[SDMX>>doc:sdmx:Glossary.Statistical data and metadata exchange.WebHome]] offers several equivalent formats for describing data and [[structural metadata>>doc:sdmx:Glossary.Structural metadata.WebHome]], optimized for use in different applications. Although all of these formats are derived directly from the SDM-IM, and are thus equivalent, the syntaxes used to express the model place some restrictions on their use. Also, different optimizations provide different capabilities. This section describes these differences, and provides some rules for applications which may need to support more than one [[SDMX>>doc:sdmx:Glossary.Statistical data and metadata exchange.WebHome]] format or syntax. This section is constrained to the Data Structure Definitionand the Date Set.
62
63 === 3.3.1 Format Optimizations and Differences ===
64
65 The following section provides a brief overview of the differences between the various [[SDMX>>doc:sdmx:Glossary.Statistical data and metadata exchange.WebHome]] formats.
66
67 (% style="color:#e74c3c" %)Version(%%) 2.0 was characterised by 4 data messages, each with a distinct format: Generic, Compact, Cross-Sectional and Utility. Because of the design, data in some formats could not always be related to another format. In (% style="color:#e74c3c" %)version(%%) 2.1, this issue has been addressed by merging some formats and eliminating others. As a result, in [[SDMX>>doc:sdmx:Glossary.Statistical data and metadata exchange.WebHome]] 2.1 there are just two types of data formats: //GenericData// and //StructureSpecificData// (i.e. specific to one [[Data Structure Definition>>doc:sdmx:Glossary.Data structure definition.WebHome]]).
68
69 Both of these formats are now flexible enough to allow for data to be oriented in series with any [[dimension>>doc:sdmx:Glossary.Dimension.WebHome]] used to disambiguate the observations (as opposed to only time or a cross sectional [[measure>>doc:sdmx:Glossary.Measure.WebHome]] in (% style="color:#e74c3c" %)version(%%) 2.0). The formats have also been expanded to allow for ungrouped observations.
70
71 To allow for applications which only understand time series data, variations of these formats have been introduced in the form of two data messages; //GenericTimeSeriesData// and //StructureSpecificTimeSeriesData//. It is important to note that these variations are built on the same root structure and can be processed in the same manner as the base format so that they do NOT introduce additional processing requirements.
72
73 **//Structure Definition//**
74
75 The [[SDMX-ML>>doc:sdmx:Glossary.SDMX-ML.WebHome]] Structure Message supports the use of [[annotations>>doc:sdmx:Glossary.Annotation.WebHome]] to the structure, which is not supported by the [[SDMX-EDI>>doc:sdmx:Glossary.SDMX-EDI.WebHome]] syntax.
76
77 The [[SDMX-ML>>doc:sdmx:Glossary.SDMX-ML.WebHome]] Structure Message allows for the structures on which a [[Data Structure Definition>>doc:sdmx:Glossary.Data structure definition.WebHome]] depends – that is, codelists and (% style="color:#e74c3c" %)concepts(%%) – to be either included in the message or to be referenced by the message containing the [[data structure definition>>doc:sdmx:Glossary.Data structure definition.WebHome]]. XML syntax is designed to leverage URIs and other Internet-based referencing mechanisms, and these are used in the [[SDMX-ML>>doc:sdmx:Glossary.SDMX-ML.WebHome]] message. This option is not available to those using the [[SDMX-EDI>>doc:sdmx:Glossary.SDMX-EDI.WebHome]] structure message.
78
79 **//Validation//**
80
81 [[SDMX-EDI>>doc:sdmx:Glossary.SDMX-EDI.WebHome]] – as is typical of EDIFACT syntax messages – leaves validation to dedicated applications (“validation” being the checking of syntax, data typing, and adherence of the data message to the structure as described in the structural definition.)
82
83 The [[SDMX-ML>>doc:sdmx:Glossary.SDMX-ML.WebHome]] Generic Data Message also leaves validation above the XML syntax (% style="color:#e74c3c" %)level(%%) to the application.
84
85 The [[SDMX-ML>>doc:sdmx:Glossary.SDMX-ML.WebHome]] [[DSD>>doc:sdmx:Glossary.Data structure definition.WebHome]]-specific messages will allow validation of XML syntax and datatyping to be performed with a generic XML parser, and enforce agreement between the structural definition and the data to a moderate degree with the same tool.
86
87 //Update and Delete Messages and Documentation Messages//
88
89 All [[SDMX>>doc:sdmx:Glossary.Statistical data and metadata exchange.WebHome]] data messages allow for both delete messages and messages consisting of only data or only documentation.
90
91 **//Character Encodings//**
92
93 All [[SDMX-ML>>doc:sdmx:Glossary.SDMX-ML.WebHome]] messages use the UTF-8 encoding, while [[SDMX-EDI>>doc:sdmx:Glossary.SDMX-EDI.WebHome]] uses the ISO 8879-1 character encoding. There is a greater capacity with UTF-8 to express some character sets (see the “APPENDIX: (% style="color:#e74c3c" %)MAP(%%) OF ISO 8859-1 (UNOC) CHARACTER SET (LATIN 1 OR “WESTERN”) in the document “SYNTAX AND DOCUMENTATION (% style="color:#e74c3c" %)VERSION(%%) 2.0”.) Many transformation tools are available which allow XML instances with UTF-8 encodings to be expressed as ISO 8879-1-encoded characters, and to transform UTF-8 into ISO 8879-1. Such tools should be used when transforming [[SDMX-ML>>doc:sdmx:Glossary.SDMX-ML.WebHome]] messages into [[SDMX-EDI>>doc:sdmx:Glossary.SDMX-EDI.WebHome]] messages and vice-versa.
94
95 **//Data Typing//**
96
97 The XML syntax and EDIFACT syntax have different data-typing mechanisms. The section below provides a set of conventions to be observed when support for messages in both syntaxes is required. For more information on the [[SDMX-ML>>doc:sdmx:Glossary.SDMX-ML.WebHome]] [[representations>>doc:sdmx:Glossary.Representation.WebHome]] of data, see below.
98
99 === 3.3.2 Data Types ===
100
101 The XML syntax has a very different mechanism for data-typing than the EDIFACT syntax, and this difference may create some difficulties for applications which support both EDIFACT-based and XML-based [[SDMX>>doc:sdmx:Glossary.Statistical data and metadata exchange.WebHome]] data formats. This section provides a set of conventions for the expression in data in all formats, to allow for clean interoperability between them.
102
103 It should be noted that this section does not address character encodings – it is assumed that conversion software will include the use of transformations which will (% style="color:#e74c3c" %)map(%%) between the ISO 8879-1 encoding of the [[SDMX-EDI>>doc:sdmx:Glossary.SDMX-EDI.WebHome]] format and the UTF-8 encoding of the [[SDMX-ML>>doc:sdmx:Glossary.SDMX-ML.WebHome]] formats.
104
105 Note that the following conventions may be followed for ease of interoperation between EDIFACT and XML [[representations>>doc:sdmx:Glossary.Representation.WebHome]] of the data and metadata. For implementations in which no transformation between EDIFACT and XML syntaxes is foreseen, the restrictions below need not apply.
106
107 1. **Identifiers** are:
108 1*. Maximum 18 characters;
109 1*. Any of A..Z (upper case alphabetic), 0..9 (numeric), _ (underscore);
110 1*. The first character is alphabetic.
111 1. **Names** are:
112 1*. Maximum 70 characters.
113 1*. From ISO 8859-1 character set (including accented characters)
114 1. **Descriptions **are:
115 1*. Maximum 350 characters;
116 1*. From ISO 8859-1 character set.
117 1. **Code values** are:
118 1*. Maximum 18 characters;
119 1*. Any of A..Z (upper case alphabetic), 0..9 (numeric), _ (underscore), / (solidus, slash), = (equal sign), - (hyphen);
120
121 However, [[code>>doc:sdmx:Glossary.Code.WebHome]] values providing values to a [[dimension>>doc:sdmx:Glossary.Dimension.WebHome]] must use only the following characters:
122
123 A..Z (upper case alphabetic), 0..9 (numeric), _ (underscore)
124
125 **5. Observation values** are:
126
127 * [[Decimal>>doc:sdmx:Glossary.Decimals.WebHome]] numerics (signed only if they are negative);
128 * The maximum number of significant figures is:
129 * 15 for a positive number
130 * 14 for a positive [[decimal>>doc:sdmx:Glossary.Decimals.WebHome]] or a negative integer
131 * 13 for a negative [[decimal>>doc:sdmx:Glossary.Decimals.WebHome]]
132 * Scientific notation may be used.
133
134 **6. Uncoded statistical concept** text values are:
135
136 * Maximum 1050 characters;
137 * From ISO 8859-1 character set.
138
139 **7. Time series keys**:
140
141 In principle, the maximum permissible length of time [[series keys>>doc:sdmx:Glossary.Series key.WebHome]] used in a data exchange does not need to be restricted. However, for working purposes, an effort is made to limit the maximum length to 35 characters; in this length, also (for SDMXEDI) one (separator) position is included between all successive [[dimension>>doc:sdmx:Glossary.Dimension.WebHome]] values; this means that the maximum length allowed for a pure [[series key>>doc:sdmx:Glossary.Series key.WebHome]] (concatenation of [[dimension>>doc:sdmx:Glossary.Dimension.WebHome]] values) can be less than 35 characters. The separator character is a colon (“:”) by conventional usage.
142
143 == 3.4 SDMX-ML and SDMX-EDI Best Practices ==
144
145 === 3.4.1 Reporting and Dissemination Guidelines ===
146
147 ==== 3.4.1.1 Central Institutions and Their Role in Statistical Data Exchanges ====
148
149 Central institutions are the organisations to which other partner institutions "report" statistics. These statistics are used by central institutions either to compile aggregates and/or they are put together and made available in a uniform manner (e.g. on-line or on a CD-ROM or through file transfers). Therefore, central institutions receive data from other institutions and, usually, they also "disseminate" data to individual and/or institutions for end-use. Within a country, a NSI or a national central bank (NCB) plays, of course, a central institution role as it collects data from other entities and it disseminates statistical information to end users. In [[SDMX>>doc:sdmx:Glossary.Statistical data and metadata exchange.WebHome]] the role of central institution is very important: every statistical message is based on underlying structural definitions (statistical (% style="color:#e74c3c" %)concepts(%%), [[code lists>>doc:sdmx:Glossary.Code list.WebHome]], DSDs) which have been devised by a particular agency, usually a central institution. Such an institution plays the role of the reference "structural definitions [[maintenance agency>>doc:sdmx:Glossary.Maintenance agency.WebHome]] for the corresponding messages which are exchanged. Of course, two institutions could exchange data using/referring to structural information devised by a third institution.
150
151 Central institutions can play a double role:
152
153 * collecting and further disseminating statistics;
154 * devising structural definitions for use in data exchanges.
155
156 ==== 3.4.1.2 Defining Data Structure Definitions (DSDs) ====
157
158 The following guidelines are suggested for building a [[DSD>>doc:sdmx:Glossary.Data structure definition.WebHome]]. However, it is expected that these guidelines will be considered by central institutions when devising new DSDs.
159
160 (% class="wikigeneratedid" id="HDimensions2CAttributesandCodeLists" %)
161 __Dimensions, Attributes and Code Lists__
162
163 **//Avoid [[dimensions>>doc:sdmx:Glossary.Dimension.WebHome]] that are not appropriate for all the series in the [[data structure definition>>doc:sdmx:Glossary.Data structure definition.WebHome]].//** If some [[dimensions>>doc:sdmx:Glossary.Dimension.WebHome]] are not applicable (this is evident from the need to have a [[code>>doc:sdmx:Glossary.Code.WebHome]] in a [[code list>>doc:sdmx:Glossary.Code list.WebHome]] which is marked as “not applicable”, “not relevant” or “total”) for some series then consider moving these series to a new [[data structure definition>>doc:sdmx:Glossary.Data structure definition.WebHome]] in which these [[dimensions>>doc:sdmx:Glossary.Dimension.WebHome]] are dropped from the key structure. This is a judgement call as it is sometimes difficult to achieve this without increasing considerably the number of DSDs.
164
165 **//Devise DSDs with a small number of [[Dimensions>>doc:sdmx:Glossary.Dimension.WebHome]] for public viewing of data.//** A [[DSD>>doc:sdmx:Glossary.Data structure definition.WebHome]] with the number [[dimensions>>doc:sdmx:Glossary.Dimension.WebHome]] in excess 6 or 7 is often difficult for non specialist users to understand. In these cases it is better to have a larger number of DSDs with smaller “cubes” of data, or to eliminate [[dimensions>>doc:sdmx:Glossary.Dimension.WebHome]] and aggregate the data at a higher (% style="color:#e74c3c" %)level(%%). Dissemination of data on the web is a growing use case for the [[SDMX>>doc:sdmx:Glossary.Statistical data and metadata exchange.WebHome]] standards: the differentiation of observations by dimensionality which are necessary for statisticians and economists are often obscure to public consumers who may not always understand the semantic of the differentiation.
166
167 **//Avoid composite [[dimensions>>doc:sdmx:Glossary.Dimension.WebHome]].//** Each [[dimension>>doc:sdmx:Glossary.Dimension.WebHome]] should correspond to a single characteristic of the data, not to a combination of characteristics.
168
169 **//Consider the inclusion of the following [[attributes>>doc:sdmx:Glossary.Attribute.WebHome]]//**. Once the key structure of a [[data structure definition>>doc:sdmx:Glossary.Data structure definition.WebHome]] has been decided, then the set of (preferably mandatory) [[attributes>>doc:sdmx:Glossary.Attribute.WebHome]] of this [[data structure definition>>doc:sdmx:Glossary.Data structure definition.WebHome]] has to be defined. In general, some statistical (% style="color:#e74c3c" %)concepts(%%) are deemed necessary across all [[Data Structure Definitions>>doc:sdmx:Glossary.Data structure definition.WebHome]] to qualify the contained information. Examples of these are:
170
171 * A descriptive [[title>>doc:sdmx:Glossary.Title.WebHome]] for the series (this is most useful for dissemination of data for viewing e.g. on the web)
172 * Collection (e.g. end of period, averaged or summed over period)
173 * Unit (e.g. [[currency>>doc:sdmx:Glossary.Currency.WebHome]] of denomination)
174 * Unit multiplier (e.g. expressed in millions)
175 * Availability (which institutions can a series become available to)
176 * Decimals (i.e. number of [[decimal>>doc:sdmx:Glossary.Decimals.WebHome]] digits used in numerical observations)
177 * [[Observation Status>>doc:sdmx:Glossary.Observation status.WebHome]] (e.g. estimate, provisional, normal)
178
179 Moreover, additional [[attributes>>doc:sdmx:Glossary.Attribute.WebHome]] may be considered as mandatory when a specific [[data structure definition>>doc:sdmx:Glossary.Data structure definition.WebHome]] is defined.
180
181 **//Avoid creating a new [[code list>>doc:sdmx:Glossary.Code list.WebHome]] where one already exists.//** It is highly recommended that structural definitions and [[code lists>>doc:sdmx:Glossary.Code list.WebHome]] be consistent with internationally agreed standard methodologies, wherever they exist, e.g., System of National Accounts 1993; Balance of Payments Manual, Fifth Edition; Monetary and Financial Statistics Manual; Government Finance Statistics Manual, etc. When setting-up a new data exchange, the following order of priority is suggested when considering the use of [[code lists>>doc:sdmx:Glossary.Code list.WebHome]]:
182
183 * international standard [[code lists>>doc:sdmx:Glossary.Code list.WebHome]];
184 * international [[code lists>>doc:sdmx:Glossary.Code list.WebHome]] supplemented by other international and/or regional institutions;
185 * standardised lists used already by international institutions;
186 * new [[code lists>>doc:sdmx:Glossary.Code list.WebHome]] agreed between two international or regional institutions;
187 * new specific [[code lists>>doc:sdmx:Glossary.Code list.WebHome]].
188
189 The same [[code list>>doc:sdmx:Glossary.Code list.WebHome]] can be used for several statistical (% style="color:#e74c3c" %)concepts(%%), within a [[data structure definition>>doc:sdmx:Glossary.Data structure definition.WebHome]] or across DSDs. Note that [[SDMX>>doc:sdmx:Glossary.Statistical data and metadata exchange.WebHome]] has recognised that these classifications are often quite large and the usage of [[codes>>doc:sdmx:Glossary.Code.WebHome]] in any one [[DSD>>doc:sdmx:Glossary.Data structure definition.WebHome]] is only a small extract of the full [[code list>>doc:sdmx:Glossary.Code list.WebHome]]. In this (% style="color:#e74c3c" %)version(%%) of the standard it is possible to exchange and disseminate a **partial [[code list>>doc:sdmx:Glossary.Code list.WebHome]]** which is extracted from the full [[code list>>doc:sdmx:Glossary.Code list.WebHome]] and which supports the [[dimension>>doc:sdmx:Glossary.Dimension.WebHome]] values valid for a particular [[DSD>>doc:sdmx:Glossary.Data structure definition.WebHome]].
190
191 __Data Structure Definition Structure__
192
193 The following items have to be specified by a structural definitions [[maintenance agency>>doc:sdmx:Glossary.Maintenance agency.WebHome]] when defining a new [[data structure definition>>doc:sdmx:Glossary.Data structure definition.WebHome]]:
194
195 [[Data structure definition>>doc:sdmx:Glossary.Data structure definition.WebHome]] ([[DSD>>doc:sdmx:Glossary.Data structure definition.WebHome]]) identification:
196
197 * [[DSD>>doc:sdmx:Glossary.Data structure definition.WebHome]] identifier
198 * [[DSD>>doc:sdmx:Glossary.Data structure definition.WebHome]] name
199
200 A list of metadata (% style="color:#e74c3c" %)concepts(%%) assigned as [[dimensions>>doc:sdmx:Glossary.Dimension.WebHome]] of the [[data structure definition>>doc:sdmx:Glossary.Data structure definition.WebHome]]. For each:
201
202 * (statistical) (% style="color:#e74c3c" %)concept(%%) identifier
203 * ordinal number of the [[dimension>>doc:sdmx:Glossary.Dimension.WebHome]] in the key structure ([[SDMX-EDI>>doc:sdmx:Glossary.SDMX-EDI.WebHome]] only)
204 * [[code list>>doc:sdmx:Glossary.Code list.WebHome]] identifier (Id, (% style="color:#e74c3c" %)version(%%), [[maintenance agency>>doc:sdmx:Glossary.Maintenance agency.WebHome]]) if the [[representation>>doc:sdmx:Glossary.Representation.WebHome]] is coded
205
206 A list of (statistical) (% style="color:#e74c3c" %)concepts(%%) assigned as [[attributes>>doc:sdmx:Glossary.Attribute.WebHome]] for the [[data structure definition>>doc:sdmx:Glossary.Data structure definition.WebHome]]. For each:
207
208 * (statistical) (% style="color:#e74c3c" %)concept(%%) identifier
209 * [[code list>>doc:sdmx:Glossary.Code list.WebHome]] identifier if the (% style="color:#e74c3c" %)concept(%%) is coded
210 * assignment status: mandatory or conditional
211 * attachment (% style="color:#e74c3c" %)level
212 * maximum text length for the uncoded (% style="color:#e74c3c" %)concepts
213 * maximum [[code>>doc:sdmx:Glossary.Code.WebHome]] length for the coded (% style="color:#e74c3c" %)concepts
214
215 A list of the [[code lists>>doc:sdmx:Glossary.Code list.WebHome]] used in the [[data structure definition>>doc:sdmx:Glossary.Data structure definition.WebHome]]. For each:
216
217 * [[code list>>doc:sdmx:Glossary.Code list.WebHome]] identifier
218 * [[code list>>doc:sdmx:Glossary.Code list.WebHome]] name
219 * [[code>>doc:sdmx:Glossary.Code.WebHome]] values and descriptions
220
221 Definition of [[data flow>>doc:sdmx:Glossary.Dataflow.WebHome]] definitions. Two (or more) partners performing data exchanges in a certain context need to agree on:
222
223 * the list of [[data set>>doc:sdmx:Glossary.Data set.WebHome]] identifiers they will be using;
224 * for each [[data flow>>doc:sdmx:Glossary.Dataflow.WebHome]]:
225 * its content and description
226 * the relevant [[DSD>>doc:sdmx:Glossary.Data structure definition.WebHome]] that defines the structure of the data reported or disseminated according the the [[dataflow>>doc:sdmx:Glossary.Dataflow.WebHome]] definition
227
228 ==== 3.4.1.3 Exchanging Attributes ====
229
230 ===== //3.4.1.3.1 Attributes on series, sibling and data set level // =====
231
232 //Static properties//.
233
234 * Upon creation of a series the sender has to provide to the receiver values for all mandatory [[attributes>>doc:sdmx:Glossary.Attribute.WebHome]]. In case they are available, values for conditional [[attributes>>doc:sdmx:Glossary.Attribute.WebHome]] should also be provided. Whereas initially this information may be provided by means other than [[SDMX-ML>>doc:sdmx:Glossary.SDMX-ML.WebHome]] or [[SDMX-EDI>>doc:sdmx:Glossary.SDMX-EDI.WebHome]] messages (e.g. paper, telephone) it is expected that partner institutions will be in a position to provide this information in [[SDMX-ML>>doc:sdmx:Glossary.SDMX-ML.WebHome]] or [[SDMX-EDI>>doc:sdmx:Glossary.SDMX-EDI.WebHome]] format over time.
235 * A centre may agree with its data exchange partners special procedures for authorising the setting of [[attributes>>doc:sdmx:Glossary.Attribute.WebHome]]' initial values.
236 * [[Attribute>>doc:sdmx:Glossary.Attribute.WebHome]] values at a [[data set>>doc:sdmx:Glossary.Data set.WebHome]] (% style="color:#e74c3c" %)level(%%) are set and maintained exclusively by the centre administrating the exchanged [[data set>>doc:sdmx:Glossary.Data set.WebHome]].
237
238 //Communication of changes// to the centre.
239
240 * Following the creation of a series, the [[attribute>>doc:sdmx:Glossary.Attribute.WebHome]] values do not have to be reported again by senders, as long as they do not change.
241 * Whenever changes in [[attribute>>doc:sdmx:Glossary.Attribute.WebHome]] values for a series (or [[sibling group>>doc:sdmx:Glossary.Sibling group.WebHome]]) occur, the reporting institutions should report either all [[attribute>>doc:sdmx:Glossary.Attribute.WebHome]] values again (this is the recommended option) or only the [[attribute>>doc:sdmx:Glossary.Attribute.WebHome]] values which have changed. This applies both to the mandatory and the conditional [[attributes>>doc:sdmx:Glossary.Attribute.WebHome]]. For example, if a previously reported value for a conditional [[attribute>>doc:sdmx:Glossary.Attribute.WebHome]] is no longer valid, this has to be reported to the centre.
242 * A centre may agree with its data exchange partners special procedures for authorising modifications in the [[attribute>>doc:sdmx:Glossary.Attribute.WebHome]] values.
243
244 Communication of observation (% style="color:#e74c3c" %)level(%%) [[attributes>>doc:sdmx:Glossary.Attribute.WebHome]] “[[observation status>>doc:sdmx:Glossary.Observation status.WebHome]]”, "observation [[confidentiality>>doc:sdmx:Glossary.Confidentiality.WebHome]]", "observation pre-break".
245
246 * In [[SDMX-EDI>>doc:sdmx:Glossary.SDMX-EDI.WebHome]], the observation (% style="color:#e74c3c" %)level(%%) [[attribute>>doc:sdmx:Glossary.Attribute.WebHome]] “[[observation status>>doc:sdmx:Glossary.Observation status.WebHome]]” is part of the fixed syntax of the ARR segment used for observation reporting. Whenever an observation is exchanged, the corresponding [[observation status>>doc:sdmx:Glossary.Observation status.WebHome]] must also be exchanged attached to the observation, regardless of whether it has changed or not since the previous data exchange. This rule also applies to the use of the [[SDMX-ML>>doc:sdmx:Glossary.SDMX-ML.WebHome]] formats, although the syntax does not necessarily require this.
247 * If the “[[observation status>>doc:sdmx:Glossary.Observation status.WebHome]]” changes and the observation remains unchanged, both [[components>>doc:sdmx:Glossary.Component.WebHome]] would have to be reported.
248 * For [[Data Structure Definitions>>doc:sdmx:Glossary.Data structure definition.WebHome]] having also the observation (% style="color:#e74c3c" %)level(%%) [[attributes>>doc:sdmx:Glossary.Attribute.WebHome]] “observation [[confidentiality>>doc:sdmx:Glossary.Confidentiality.WebHome]]” and "observation pre-break" defined, this rule applies to these [[attribute>>doc:sdmx:Glossary.Attribute.WebHome]] as well: if an institution receives from another institution an observation with an [[observation status>>doc:sdmx:Glossary.Observation status.WebHome]] [[attribute>>doc:sdmx:Glossary.Attribute.WebHome]] only attached, this means that the associated observation [[confidentiality>>doc:sdmx:Glossary.Confidentiality.WebHome]] and prebreak observation [[attributes>>doc:sdmx:Glossary.Attribute.WebHome]] either never existed or from now they do not have a value for this observation.
249
250 === 3.4.2 Best Practices for Batch Data Exchange ===
251
252 ==== 3.4.2.1 Introduction ====
253
254 Batch data exchange is the exchange and maintenance of entire databases between counterparties. It is an activity that often employs [[SDMX-EDI>>doc:sdmx:Glossary.SDMX-EDI.WebHome]] formats, and might also use the [[SDMX-ML>>doc:sdmx:Glossary.SDMX-ML.WebHome]] [[DSD>>doc:sdmx:Glossary.Data structure definition.WebHome]]-specific [[data set>>doc:sdmx:Glossary.Data set.WebHome]]. The following points apply equally to both formats.
255
256 ==== 3.4.2.2 Positioning of the Dimension "Frequency" ====
257
258 The position of the “frequency” [[dimension>>doc:sdmx:Glossary.Dimension.WebHome]] is unambiguously identified in the [[data structure definition>>doc:sdmx:Glossary.Data structure definition.WebHome]]. Moreover, most central institutions devising structural definitions have decided to assign to this [[dimension>>doc:sdmx:Glossary.Dimension.WebHome]] the first position in the key structure. This facilitates the easy identification of this [[dimension>>doc:sdmx:Glossary.Dimension.WebHome]], something that it is necessary to frequency's crucial role in several database systems and in attaching [[attributes>>doc:sdmx:Glossary.Attribute.WebHome]] at the “sibling” group (% style="color:#e74c3c" %)level(%%).
259
260 ==== 3.4.2.3 Identification of Data Structure Definitions (DSDs) ====
261
262 In order to facilitate the easy and immediate recognition of the structural definition [[maintenance agency>>doc:sdmx:Glossary.Maintenance agency.WebHome]] that defined a [[data structure definition>>doc:sdmx:Glossary.Data structure definition.WebHome]], most central institutions devising structural definitions use the first characters of the [[data structure definition>>doc:sdmx:Glossary.Data structure definition.WebHome]] identifiers to identify their institution: e.g. BIS_EER, EUROSTAT_BOP_01, ECB_BOP1, etc.
263
264 ==== 3.4.2.4 Identification of the Data Flows ====
265
266 In order to facilitate the easy and immediate recognition of the institution administrating a [[data flow>>doc:sdmx:Glossary.Dataflow.WebHome]] definitions, many central institutions prefer to use the first characters of the [[data flow>>doc:sdmx:Glossary.Dataflow.WebHome]] definition identifiers to identify their institution: e.g. BIS_EER, ECB_BOP1, ECB_BOP1, etc. Note that in GESMES/TS the [[Data Set>>doc:sdmx:Glossary.Data set.WebHome]] plays the role of the [[data flow>>doc:sdmx:Glossary.Dataflow.WebHome]] definition (see //[[DataSet>>doc:sdmx:Glossary.Data set.WebHome]] //in the [[SDMX-IM>>doc:sdmx:Glossary.SDMX Information Model.WebHome]]//)//.
267
268 The statistical information in [[SDMX>>doc:sdmx:Glossary.Statistical data and metadata exchange.WebHome]] is broken down into two fundamental parts - [[structural metadata>>doc:sdmx:Glossary.Structural metadata.WebHome]] (comprising the [[Data Structure Definition>>doc:sdmx:Glossary.Data structure definition.WebHome]], and associated (% style="color:#e74c3c" %)Concepts(%%) and [[Code Lists>>doc:sdmx:Glossary.Code list.WebHome]]) - see Framework for Standards -, and observational data (the [[DataSet>>doc:sdmx:Glossary.Data set.WebHome]]). This is an important distinction, with specific terminology associated with each part. Data - which is typically a set of numeric observations at specific points in time - is organized into [[data sets>>doc:sdmx:Glossary.Data set.WebHome]] (//[[DataSet>>doc:sdmx:Glossary.Data set.WebHome]]//) These [[data sets>>doc:sdmx:Glossary.Data set.WebHome]] are structured according to a specific [[Data Structure Definition>>doc:sdmx:Glossary.Data structure definition.WebHome]] (//DataStructureDefinition//) and are described in the [[data flow>>doc:sdmx:Glossary.Dataflow.WebHome]] definition (//DataflowDefinition)// The [[Data Structure Definition>>doc:sdmx:Glossary.Data structure definition.WebHome]] describes the metadata that allows an understanding of what is expressed in the [[data set>>doc:sdmx:Glossary.Data set.WebHome]], whilst the [[data flow>>doc:sdmx:Glossary.Dataflow.WebHome]] definition provides the identifier and other important information (such as the periodicity of reporting) that is common to all of its [[component>>doc:sdmx:Glossary.Component.WebHome]] [[data sets>>doc:sdmx:Glossary.Data set.WebHome]].
269
270 Note that the role of the [[Data Flow>>doc:sdmx:Glossary.Dataflow.WebHome]] (called //DataflowDefintion// in the model) and [[Data Set>>doc:sdmx:Glossary.Data set.WebHome]] is very specific in the model, and the terminology used may not be the same as used in all organisations, and specifically the term [[Data Set>>doc:sdmx:Glossary.Data set.WebHome]] is used differently in [[SDMX>>doc:sdmx:Glossary.Statistical data and metadata exchange.WebHome]] than in GESMES/TS. Essentially the GESMES/TS term [[Data Set>>doc:sdmx:Glossary.Data set.WebHome]] is, in [[SDMX>>doc:sdmx:Glossary.Statistical data and metadata exchange.WebHome]], the [[Dataflow>>doc:sdmx:Glossary.Dataflow.WebHome]] Definition" whist the term [[Data Set>>doc:sdmx:Glossary.Data set.WebHome]] in [[SDMX>>doc:sdmx:Glossary.Statistical data and metadata exchange.WebHome]] is used to describe the "container" for an instance of the data.
271
272 ==== 3.4.2.5 Special Issues ====
273
274 ===== 3.4.2.5.1 "Frequency" related issues =====
275
276 **//Special frequencies.//** The issue of data collected at special (regular or irregular) intervals at a lower than daily frequency (e.g. 24 or 36 or 48 observations per year, on irregular days during the year) is not extensively discussed here. However, for data exchange purposes:
277
278 * such data can be (% style="color:#e74c3c" %)mapped(%%) into a series with daily frequency; this daily series will only hold observations for those days on which the measured event takes place;
279 * if the collection intervals are regular, additional values to the existing frequency [[code list>>doc:sdmx:Glossary.Code list.WebHome]](s) could be added in the future.
280
281 **//Tick data.//** The issue of data collected at irregular intervals at a higher than daily frequency (e.g. tick-by-tick data) is not discussed here either. However, for data exchange purposes, such series can already be exchanged in the [[SDMX-EDI>>doc:sdmx:Glossary.SDMX-EDI.WebHome]] format by using the option to send observations with the associated time stamp.
282
283 = 4 General Notes for Implementers =
284
285 This section discusses a number of topics other than the exchange of [[data sets>>doc:sdmx:Glossary.Data set.WebHome]] in [[SDMX-ML>>doc:sdmx:Glossary.SDMX-ML.WebHome]] and [[SDMX-EDI>>doc:sdmx:Glossary.SDMX-EDI.WebHome]]. Supported only in [[SDMX-ML>>doc:sdmx:Glossary.SDMX-ML.WebHome]], these topics include the use of the [[reference metadata>>doc:sdmx:Glossary.Reference metadata.WebHome]] mechanism in [[SDMX>>doc:sdmx:Glossary.Statistical data and metadata exchange.WebHome]], the use of [[Structure Sets>>doc:sdmx:Glossary.Structure set.WebHome]] and [[Reporting Taxonomies>>doc:sdmx:Glossary.Reporting taxonomy.WebHome]], the use of Processes, a discussion of time and data-typing, and some of the conventional mechanisms within the [[SDMX-ML>>doc:sdmx:Glossary.SDMX-ML.WebHome]] Structure message regarding versioning and external referencing.
286
287 This section does not go into great detail on these topics, but provides a useful overview of these features to assist implementors in further use of the parts of the specification which are relevant to them.
288
289 == 4.1 Representations ==
290
291 There are several different [[representations>>doc:sdmx:Glossary.Representation.WebHome]] in [[SDMX-ML>>doc:sdmx:Glossary.SDMX-ML.WebHome]], taken from XML Schemas and common programming languages. The table below describes the various [[representations>>doc:sdmx:Glossary.Representation.WebHome]] which are found in [[SDMX-ML>>doc:sdmx:Glossary.SDMX-ML.WebHome]], and their equivalents.
292
293 (% style="width:912.294px" %)
294 |(% style="width:172px" %)**SDMX-ML Data Type**|(% style="width:204px" %)**XML Schema Data Type**|(% style="width:189px" %)**.NET Framework Type**|(% style="width:342px" %)(((
295 **Java Data Type **
296 )))
297 |(% style="width:172px" %)String|(% style="width:204px" %)xsd:string|(% style="width:189px" %)System.String|(% style="width:342px" %)java.lang.String
298 |(% style="width:172px" %)Big Integer|(% style="width:204px" %)xsd:integer|(% style="width:189px" %)System.Decimal|(% style="width:342px" %)java.math.BigInteg er
299 |(% style="width:172px" %)Integer|(% style="width:204px" %)xsd:int|(% style="width:189px" %)System.Int32|(% style="width:342px" %)int
300 |(% style="width:172px" %)Long|(% style="width:204px" %)xsd.long|(% style="width:189px" %)System.Int64|(% style="width:342px" %)long
301 |(% style="width:172px" %)Short|(% style="width:204px" %)xsd:short|(% style="width:189px" %)System.Int16|(% style="width:342px" %)short
302 |(% style="width:172px" %)Decimal|(% style="width:204px" %)xsd:decimal|(% style="width:189px" %)System.Decimal|(% style="width:342px" %)java.math.BigDecim al
303 |(% style="width:172px" %)Float|(% style="width:204px" %)xsd:float|(% style="width:189px" %)System.Single|(% style="width:342px" %)float
304 |(% style="width:172px" %)Double|(% style="width:204px" %)xsd:double|(% style="width:189px" %)System.Double|(% style="width:342px" %)double
305 |(% style="width:172px" %)Boolean|(% style="width:204px" %)xsd:boolean|(% style="width:189px" %)System.Boolean|(% style="width:342px" %)boolean
306 |(% style="width:172px" %)URI|(% style="width:204px" %)xsd:anyURI|(% style="width:189px" %)System.Uri|(% style="width:342px" %)Java.net.URI or java.lang.String
307 |(% style="width:172px" %)DateTime|(% style="width:204px" %)xsd:dateTime|(% style="width:189px" %)System.DateTime|(% style="width:342px" %)javax.xml.datatype .XMLGregorianCalen dar
308 |(% style="width:172px" %)Time|(% style="width:204px" %)xsd:time|(% style="width:189px" %)System.DateTime|(% style="width:342px" %)javax.xml.datatype .XMLGregorianCalen dar
309 |(% style="width:172px" %)GregorianYear|(% style="width:204px" %)xsd:gYear|(% style="width:189px" %)System.DateTime|(% style="width:342px" %)javax.xml.datatype .XMLGregorianCalen dar
310 |(% style="width:172px" %)GregorianMonth|(% style="width:204px" %)xsd:gYearMonth|(% style="width:189px" %)System.DateTime|(% style="width:342px" %)javax.xml.datatype .XMLGregorianCalen dar
311 |(% style="width:172px" %)GregorianDay|(% style="width:204px" %)xsd:date|(% style="width:189px" %)System.DateTime|(% style="width:342px" %)javax.xml.datatype .XMLGregorianCalen dar
312 |(% style="width:172px" %)(((
313 Day, MonthDay, Month
314 )))|(% style="width:204px" %)xsd:g*|(% style="width:189px" %)System.DateTime|(% style="width:342px" %)javax.xml.datatype .XMLGregorianCalen dar
315 |(% style="width:172px" %)Duration|(% style="width:204px" %)xsd:duration |(% style="width:189px" %)System.TimeSpa|(% style="width:342px" %)javax.xml.datatype
316 |(% style="width:172px" %) |(% style="width:204px" %) |(% style="width:189px" %)n|(% style="width:342px" %).Duration
317
318 There are also a number of [[SDMX-ML>>doc:sdmx:Glossary.SDMX-ML.WebHome]] data types which do not have these direct correspondences, often because they are composite [[representations>>doc:sdmx:Glossary.Representation.WebHome]] or restrictions of a broader data type. For most of these, there are simple types which can be referenced from the [[SDMX>>doc:sdmx:Glossary.Statistical data and metadata exchange.WebHome]] schemas, for others a derived simple type will be necessary:
319
320 * AlphaNumeric (common:AlphaNumericType, string which only allows A-z and 0-9)
321 * Alpha (common:AlphaType, string which only allows A-z)
322 * Numeric (common:NumericType, string which only allows 0-9, but is not numeric so that is can having leading zeros)
323 * Count (xs:integer, a sequence with an interval of “1”)
324 * InclusiveValueRange (xs:decimal with the minValue and maxValue [[facets>>doc:sdmx:Glossary.Facet.WebHome]] supplying the bounds)
325 * ExclusiveValueRange (xs:decimal with the minValue and maxValue [[facets>>doc:sdmx:Glossary.Facet.WebHome]] supplying the bounds)
326 * Incremental (xs:decimal with a specified interval; the interval is typically enforced outside of the XML validation)
327 * TimeRange (common:TimeRangeType, start DateTime + Duration,)
328 * ObservationalTimePeriod (common: ObservationalTimePeriodType, a union of StandardTimePeriod and TimeRange).
329 * StandardTimePeriod (common: StandardTimePeriodType, a union of BasicTimePeriod and TimeRange).
330 * BasicTimePeriod (common: BasicTimePeriodType, a union of GregorianTimePeriod and DateTime)
331 * GregorianTimePeriod (common:GregorianTimePeriodType, a union of GregorianYear, GregorianMonth, and GregorianDay)
332 * ReportingTimePeriod (common:ReportingTimePeriodType, a union of ReportingYear, ReportingSemester, ReportingTrimester, ReportingQuarter, ReportingMonth, ReportingWeek, and ReportingDay).  ReportingYear (common:ReportingYearType)
333 * ReportingSemester (common:ReportingSemesterType)
334 * ReportingTrimester (common:ReportingTrimesterType)
335 * ReportingQuarter (common:ReportingQuarterType)
336 * ReportingMonth (common:ReportingMonthType)
337 * ReportingWeek (common:ReportingWeekType)
338 * ReportingDay (common:ReportingDayType)
339 * XHTML (common:StructuredText, allows for multi-lingual text content that has XHTML markup)
340 * KeyValues (common:DataKeyType)
341 * IdentifiableReference (types for each identifiable object)
342 * DataSetReference (common:DataSetReferenceType)
343 * AttachmentConstraintReference (common:AttachmentConstraintReferenceType)
344
345 Data types also have a set of [[facets>>doc:sdmx:Glossary.Facet.WebHome]]:
346
347 * isSequence = true | false (indicates a sequentially increasing value)
348 * minLength = positive integer (# of characters/digits)
349 * maxLength = positive integer (# of characters/digits)
350 * startValue = [[decimal>>doc:sdmx:Glossary.Decimals.WebHome]] (for numeric sequence)
351 * endValue = [[decimal>>doc:sdmx:Glossary.Decimals.WebHome]] (for numeric sequence)
352 * interval = [[decimal>>doc:sdmx:Glossary.Decimals.WebHome]] (for numeric sequence)
353 * timeInterval = duration
354 * startTime = BasicTimePeriod (for time range)
355 * endTime = BasicTimePeriod (for time range)
356 * minValue = [[decimal>>doc:sdmx:Glossary.Decimals.WebHome]] (for numeric range)
357 * maxValue = [[decimal>>doc:sdmx:Glossary.Decimals.WebHome]] (for numeric range)
358 * [[decimal>>doc:sdmx:Glossary.Decimals.WebHome]] = Integer (# of digits to right of [[decimal>>doc:sdmx:Glossary.Decimals.WebHome]] point)
359 * pattern = (a regular expression, as per W3C XML Schema)
360 * isMultiLingual = boolean (for specifying text can occur in more than one language)
361
362 Note that [[code lists>>doc:sdmx:Glossary.Code list.WebHome]] may also have textual [[representations>>doc:sdmx:Glossary.Representation.WebHome]] assigned to them, in addition to their enumeration of codes.s
363
364 == 4.2 Time and Time Format ==
365
366 === 4.2.1 Introduction ===
367
368 First, it is important to recognize that most observation times are a period. SDMX specifies precisely how Time is handled.
369
370 The representation of time is broken into a hierarchical collection of representations. A data structure definition can use of any of the representations in the hierarchy as the representation of time. This allows for the time dimension of a particular data structure definition allow for only a subset of the default representation.
371
372 The hierarchy of time formats is as follows (**bold** indicates a category which is made up of multiple formats, //italic// indicates a distinct format):
373
374 * **Observational Time Period**
375 ** **Standard Time Period**
376 *** **Basic Time Period**
377 **** **Gregorian Time Period**
378 **** //Date Time//
379 *** **Reporting Time Period**
380 ** //Time Range//
381
382 The details of these time period categories and of the distinct formats which make them up are detailed in the sections to follow.
383
384 === 4.2.2 Observational Time Period ===
385
386 This is the superset of all time [[representations>>doc:sdmx:Glossary.Representation.WebHome]] in [[SDMX>>doc:sdmx:Glossary.Statistical data and metadata exchange.WebHome]]. This allows for time to be expressed as any of the allowable formats.
387
388 === 4.2.3 Standard Time Period ===
389
390 This is the superset of any predefined [[time period>>doc:sdmx:Glossary.Time period.WebHome]] or a distinct point in time. A [[time period>>doc:sdmx:Glossary.Time period.WebHome]] consists of a distinct start and end point. If the start and end of a period are expressed as date instead of a complete date time, then it is implied that the start of the period is the beginning of the start day (i.e. 00:00:00) and the end of the period is the end of the end day (i.e. 23:59:59).
391
392 === 4.2.4 Gregorian Time Period ===
393
394 A Gregorian [[time period>>doc:sdmx:Glossary.Time period.WebHome]] is always represented by a Gregorian year, year-month, or day. These are all based on ISO 8601 dates. The [[representation>>doc:sdmx:Glossary.Representation.WebHome]] in [[SDMX-ML>>doc:sdmx:Glossary.SDMX-ML.WebHome]] messages and the period covered by each of the Gregorian [[time periods>>doc:sdmx:Glossary.Time period.WebHome]] are as follows:
395
396 **Gregorian Year:**
397 Representation: xs:gYear (YYYY)
398 Period: the start of January 1 to the end of December 31
399
400 **Gregorian Year Month**:
401 Representation: xs:gYearMonth (YYYY-MM)
402 Period: the start of the first day of the month to end of the last day of the month
403
404 **Gregorian Day**:
405 Representation: xs:date (YYYY-MM-DD)
406 Period: the start of the day (00:00:00) to the end of the day (23:59:59)
407
408 === 4.2.5 Date Time ===
409
410 This is used to unambiguously state that a date-time represents an observation at a single point in time. Therefore, if one wants to use [[SDMX>>doc:sdmx:Glossary.Statistical data and metadata exchange.WebHome]] for data which is measured at a distinct point in time rather than being reported over a period, the date-time [[representation>>doc:sdmx:Glossary.Representation.WebHome]] can be used.
411
412 [[Representation>>doc:sdmx:Glossary.Representation.WebHome]]: xs:dateTime (YYYY-MM-DDThh:mm:ss){{footnote}}The seconds can be reported fractionally{{/footnote}}
413
414 === 4.2.6 Standard Reporting Period ===
415
416 Standard reporting periods are periods of time in relation to a reporting year. Each of these standard reporting periods has a duration (based on the ISO 8601 definition) associated with it. The general format of a reporting period is as follows:
417
418 [REPORTING_YEAR]-[PERIOD_INDICATOR][PERIOD_VALUE]
419
420 Where:
421 REPORTING_YEAR represents the reporting year as four digits (YYYY) PERIOD_INDICATOR identifies the type of period which determines the duration of the period
422 PERIOD_VALUE indicates the actual period within the year
423
424 The following section details each of the standard reporting periods defined in [[SDMX>>doc:sdmx:Glossary.Statistical data and metadata exchange.WebHome]]:
425
426 **Reporting Year**:
427 Period Indicator: A
428 Period Duration: P1Y (one year)
429 Limit per year: 1
430 Representation: common:ReportingYearType (YYYY-A1, e.g. 2000-A1)
431
432 **Reporting Semester:**
433 Period Indicator: S
434 Period Duration: P6M (six months)
435 Limit per year: 2
436 Representation: common:ReportingSemesterType (YYYY-Ss, e.g. 2000-S2)
437
438 **Reporting Trimester:**
439 Period Indicator: T
440 Period Duration: P4M (four months)
441 Limit per year: 3
442 Representation: common:ReportingTrimesterType (YYYY-Tt, e.g. 2000-T3)
443
444 **Reporting Quarter:**
445 Period Indicator: Q
446 Period Duration: P3M (three months)
447 Limit per year: 4
448 Representation: common:ReportingQuarterType (YYYY-Qq, e.g. 2000-Q4)
449
450 **Reporting Month**:
451 Period Indicator: M
452 Period Duration: P1M (one month)
453 Limit per year: 1
454 Representation: common:ReportingMonthType (YYYY-Mmm, e.g. 2000-M12) Notes: The reporting month is always represented as two digits, therefore 1-9 are 0 padded (e.g. 01). This allows the values to be sorted chronologically using textual sorting methods.
455
456 **Reporting Week**:
457 Period Indicator: W
458 Period Duration: P7D (seven days)
459 Limit per year: 53
460 Representation: common:ReportingWeekType (YYYY-Www, e.g. 2000-W53)
461 Notes: There are either 52 or 53 weeks in a reporting year. This is based on the ISO 8601 definition of a week (Monday - Saturday), where the first week of a reporting year is defined as the week with the first Thursday on or after the reporting year start day.{{footnote}}ISO 8601 defines alternative definitions for the first week, all of which produce equivalent results. Any of these definitions could be substituted so long as they are in relation to the reporting year start day.{{/footnote}} The reporting week is always represented as two digits, therefore 1-9 are 0 padded (e.g. 01). This allows the values to be sorted chronologically using textual sorting methods.
462
463 **Reporting Day**:
464 Period Indicator: D
465 Period Duration: P1D (one day)
466 Limit per year: 366
467 Representation: common:ReportingDayType (YYYY-Dddd, e.g. 2000-D366) Notes: There are either 365 or 366 days in a reporting year, depending on whether the reporting year includes leap day (February 29). The reporting day is always represented as three digits, therefore 1-99 are 0 padded (e.g. 001).
468
469 This allows the values to be sorted chronologically using textual sorting methods.
470
471 The meaning of a reporting year is always based on the start day of the year and requires that the reporting year is expressed as the year at the start of the period. This start day is always the same for a reporting year, and is expressed as a day and a month (e.g. July 1). Therefore, the reporting year 2000 with a start day of July 1 begins on July 1, 2000.
472
473 A specialized [[attribute>>doc:sdmx:Glossary.Attribute.WebHome]] (reporting year start day) exists for the purpose of communicating the reporting year start day. This [[attribute>>doc:sdmx:Glossary.Attribute.WebHome]] has a fixed identifier (REPORTING_YEAR_START_DAY) and a fixed [[representation>>doc:sdmx:Glossary.Representation.WebHome]] (xs:gMonthDay) so that it can always be easily identified and processed in a data message. Although this [[attribute>>doc:sdmx:Glossary.Attribute.WebHome]] exists in specialized sub-class, it functions the same as any other [[attribute>>doc:sdmx:Glossary.Attribute.WebHome]] outside of its identification and [[representation>>doc:sdmx:Glossary.Representation.WebHome]]. It must takes its identity from a (% style="color:#e74c3c" %)concept(%%) and state its relationship with other [[components>>doc:sdmx:Glossary.Component.WebHome]] of the [[data structure definition>>doc:sdmx:Glossary.Data structure definition.WebHome]]. The ability to state this relationship allows this reporting year start day [[attribute>>doc:sdmx:Glossary.Attribute.WebHome]] to exist at the appropriate (% style="color:#e74c3c" %)levels(%%) of a data message. In the absence of this [[attribute>>doc:sdmx:Glossary.Attribute.WebHome]], the reporting year start date is assumed to be January 1; therefore if the reporting year coincides with the calendar year, this [[Attribute>>doc:sdmx:Glossary.Attribute.WebHome]] is not necessary.
474
475 Since the duration and the reporting year start day are known for any reporting period, it is possible to relate any reporting period to a distinct calendar period. The actual Gregorian calendar period covered by the reporting period can be computed as follows (based on the standard format of [REPROTING_YEAR][PERIOD_INDICATOR][PERIOD_VALUE] and the reporting year start day as [REPORTING_YEAR_START_DAY]):
476
477 **~1. Determine [REPORTING_YEAR_BASE]:**
478 Combine [REPORTING_YEAR] of the reporting period value (YYYY) with [REPORTING_YEAR_START_DAY] (MM-DD) to get a date (YYYY-MM-DD).
479 This is the [REPORTING_YEAR_START_DATE]
480 **a) If the [PERIOD_INDICATOR] is W:
481 ~1. If [REPORTING_YEAR_START_DATE] is a Friday, Saturday, or Sunday:**
482 Add^^3^^ (P3D, P2D, or P1D respectively) to the [REPORTING_YEAR_START_DATE]. The result is the [REPORTING_YEAR_BASE].
483
484 2. **If [REPORTING_YEAR_START_DATE] is a Monday, Tuesday, Wednesday, or Thursday:**
485 Add^^3^^ (P0D, -P1D, -P2D, or -P3D respectively) to the [REPORTING_YEAR_START_DATE]. The result is the [REPORTING_YEAR_BASE].
486 b) **Else:** 
487 The [REPORTING_YEAR_START_DATE] is the [REPORTING_YEAR_BASE]
488
489 **2. Determine [PERIOD_DURATION]:**
490
491 a) If the [PERIOD_INDICATOR] is A, the [PERIOD_DURATION] is P1Y.
492 b) If the [PERIOD_INDICATOR] is S, the [PERIOD_DURATION] is P6M.
493 c) If the [PERIOD_INDICATOR] is T, the [PERIOD_DURATION] is P4M.
494 d) If the [PERIOD_INDICATOR] is Q, the [PERIOD_DURATION] is P3M.
495 e) If the [PERIOD_INDICATOR] is M, the [PERIOD_DURATION] is P1M.
496 f) If the [PERIOD_INDICATOR] is W, the [PERIOD_DURATION] is P7D.
497 g) If the [PERIOD_INDICATOR] is D, the [PERIOD_DURATION] is P1D.
498
499 **3. Determine [PERIOD_START]:**
500
501 Subtract one from the [PERIOD_VALUE] and multiply this by the [PERIOD_DURATION]. Add{{footnote}}The rules for adding durations to a date time are described in the W3C XML Schema specification. See http://www.w3.org/TR/xmlschema-2/#adding-durations-to-dateTimes for further details.{{/footnote}} this to the [REPORTING_YEAR_BASE]. The result is the [PERIOD_START].
502
503 **4. Determine the [PERIOD_END]:**
504 Multiply the [PERIOD_VALUE] by the [PERIOD_DURATION]. Add{{footnote}}The rules for adding durations to a date time are described in the W3C XML Schema specification. See http://www.w3.org/TR/xmlschema-2/#adding-durations-to-dateTimes for further details.{{/footnote}} this to the [REPORTING_YEAR_BASE] add{{footnote}}The rules for adding durations to a date time are described in the W3C XML Schema specification. See http://www.w3.org/TR/xmlschema-2/#adding-durations-to-dateTimes for further details.{{/footnote}} -P1D. The result is the [PERIOD_END].
505
506 For all of these ranges, the bounds include the beginning of the [PERIOD_START] (i.e. 00:00:00) and the end of the [PERIOD_END] (i.e. 23:59:59).
507
508 **Examples:**
509
510 **2010-Q2, REPORTING_YEAR_START_DAY = ~-~-07-01 (July 1)**
511 ~1. [REPORTING_YEAR_START_DATE] = 2010-07-01
512 b) [REPORTING_YEAR_BASE] = 2010-07-01
513 [PERIOD_DURATION] = P3M
514 (2-1) * P3M = P3M
515 2010-07-01 + P3M = 2010-10-01
516 [PERIOD_START] = 2010-10-01
517 4. 2 * P3M = P6M
518 2010-07-01 + P6M = 2010-13-01 = 2011-01-01
519 2011-01-01 + -P1D = 2010-12-31
520 [PERIOD_END] = 2011-12-31
521
522 The actual calendar range covered by 2010-Q2 (assuming the reporting year begins July 1) is 2010-10-01T00:00:00/2010-12-31T23:59:59
523
524 **2011-W36, REPORTING_YEAR_START_DAY = ~-~-07-01 (July 1)**
525 ~1. [REPORTING_YEAR_START_DATE] = 2010-07-01
526 a) 2011-07-01 = Friday
527 2011-07-01 + P3D = 2011-07-04
528 [REPORTING_YEAR_BASE] = 2011-07-04
529 2. [PERIOD_DURATION] = P7D
530 3. (36-1) * P7D = P245D
531 2011-07-04 + P245D = 2012-03-05
532 [PERIOD_START] = 2012-03-05
533 4. 36 * P7D = P252D
534 2011-07-04 + P252D =2012-03-12
535 2012-03-12 + -P1D = 2012-03-11
536 [PERIOD_END] = 2012-03-11
537
538 The actual calendar range covered by 2011-W36 (assuming the reporting year begins July 1) is 2012-03-05T00:00:00/2012-03-11T23:59:59
539
540 === 4.2.7 Distinct Range ===
541
542 In the case that the reporting period does not fit into one of the prescribe periods above, a distinct time range can be used. The value of these ranges is based on the ISO 8601 time interval format of start/duration. Start can be expressed as either an ISO 8601 date or a date-time, and duration is expressed as an ISO 8601 duration. However, the duration can only be postive.
543
544 === 4.2.8 Time Format ===
545
546 In (% style="color:#e74c3c" %)version(%%) 2.0 of [[SDMX>>doc:sdmx:Glossary.Statistical data and metadata exchange.WebHome]] there is a recommendation to use the [[time format>>doc:sdmx:Glossary.Time format.WebHome]] [[attribute>>doc:sdmx:Glossary.Attribute.WebHome]] to gives additional information on the way time is represented in the message. Following an appraisal of its usefulness this is no longer required. However, it is still possible, if required , to include the [[time format>>doc:sdmx:Glossary.Time format.WebHome]] [[attribute>>doc:sdmx:Glossary.Attribute.WebHome]] in [[SDMX-ML>>doc:sdmx:Glossary.SDMX-ML.WebHome]].
547
548 (% style="width:716.835px" %)
549 |(% style="width:197px" %)**Code**|(% style="width:517px" %)**Format**
550 |(% style="width:197px" %)**OTP**|(% style="width:517px" %)Observational [[Time Period>>doc:sdmx:Glossary.Time period.WebHome]]: Superset of all [[SDMX>>doc:sdmx:Glossary.Statistical data and metadata exchange.WebHome]] [[time formats>>doc:sdmx:Glossary.Time format.WebHome]] (Gregorian [[Time Period>>doc:sdmx:Glossary.Time period.WebHome]], Reporting [[Time Period>>doc:sdmx:Glossary.Time period.WebHome]], and Time Range)
551 |(% style="width:197px" %)**STP**|(% style="width:517px" %)Standard [[Time Period>>doc:sdmx:Glossary.Time period.WebHome]]: Superset of Gregorian and Reporting [[Time Periods>>doc:sdmx:Glossary.Time period.WebHome]]
552 |(% style="width:197px" %)**GTP**|(% style="width:517px" %)Superset of all Gregorian [[Time Periods>>doc:sdmx:Glossary.Time period.WebHome]] and date-time
553 |(% style="width:197px" %)**RTP**|(% style="width:517px" %)Superset of all Reporting [[Time Periods>>doc:sdmx:Glossary.Time period.WebHome]]
554 |(% style="width:197px" %)**TR**|(% style="width:517px" %)Time Range: Start time and duration (YYYY-MMDD(Thh:mm:ss)?/)
555 |(% style="width:197px" %)**GY**|(% style="width:517px" %)Gregorian Year (YYYY)
556 |(% style="width:197px" %)**GTM**|(% style="width:517px" %)Gregorian Year Month (YYYY-MM)
557 |(% style="width:197px" %)**GD**|(% style="width:517px" %)Gregorian Day (YYYY-MM-DD)
558 |(% style="width:197px" %)**DT**|(% style="width:517px" %)Distinct Point: date-time (YYYY-MM-DDThh:mm:ss)
559 |(% style="width:197px" %)**RY**|(% style="width:517px" %)Reporting Year (YYYY-A1)
560 |(% style="width:197px" %)**RS**|(% style="width:517px" %)Reporting Semester (YYYY-Ss)
561 |(% style="width:197px" %)**RT**|(% style="width:517px" %)Reporting Trimester (YYYY-Tt)
562 |(% style="width:197px" %)**RQ**|(% style="width:517px" %)Reporting Quarter (YYYY-Qq)
563 |(% style="width:197px" %)**RM**|(% style="width:517px" %)Reporting Month (YYYY-Mmm)
564 |(% style="width:197px" %)**[[Code>>doc:sdmx:Glossary.Code.WebHome]]**|(% style="width:517px" %)**Format**
565 |(% style="width:197px" %)**RW**|(% style="width:517px" %)Reporting Week (YYYY-Www)
566 |(% style="width:197px" %)**RD**|(% style="width:517px" %)Reporting Day (YYYY-Dddd)
567
568 **Table 1: SDMX-ML Time Format Codes**
569
570 === 4.2.9 Transformation between SDMX-ML and SDMX-EDI ===
571
572 When converting [[SDMX-ML>>doc:sdmx:Glossary.SDMX-ML.WebHome]] [[data structure definitions>>doc:sdmx:Glossary.Data structure definition.WebHome]] to [[SDMX-EDI>>doc:sdmx:Glossary.SDMX-EDI.WebHome]] [[data structure definitions>>doc:sdmx:Glossary.Data structure definition.WebHome]], only the identifier of the [[time format>>doc:sdmx:Glossary.Time format.WebHome]] [[attribute>>doc:sdmx:Glossary.Attribute.WebHome]] will be retained. The [[representation>>doc:sdmx:Glossary.Representation.WebHome]] of the [[attribute>>doc:sdmx:Glossary.Attribute.WebHome]] will be converted from the [[SDMX-ML>>doc:sdmx:Glossary.SDMX-ML.WebHome]] format to the fixed [[SDMX-EDI>>doc:sdmx:Glossary.SDMX-EDI.WebHome]] [[code list>>doc:sdmx:Glossary.Code list.WebHome]]. If the [[SDMX-ML>>doc:sdmx:Glossary.SDMX-ML.WebHome]] [[data structure definition>>doc:sdmx:Glossary.Data structure definition.WebHome]] does not define a [[time format>>doc:sdmx:Glossary.Time format.WebHome]] [[attribute>>doc:sdmx:Glossary.Attribute.WebHome]], then one will be automatically created with the identifier "TIME_FORMAT".
573
574 When converting [[SDMX-ML>>doc:sdmx:Glossary.SDMX-ML.WebHome]] data to [[SDMX-EDI>>doc:sdmx:Glossary.SDMX-EDI.WebHome]], the source [[time format>>doc:sdmx:Glossary.Time format.WebHome]] [[attribute>>doc:sdmx:Glossary.Attribute.WebHome]] will be irrelevant. Since the [[SDMX-ML>>doc:sdmx:Glossary.SDMX-ML.WebHome]] time [[representation>>doc:sdmx:Glossary.Representation.WebHome]] types are not ambiguous, the target [[time format>>doc:sdmx:Glossary.Time format.WebHome]] can be determined from the source time value directly. For example, if the [[SDMX-ML>>doc:sdmx:Glossary.SDMX-ML.WebHome]] time is 2000-Q2 the [[SDMX-EDI>>doc:sdmx:Glossary.SDMX-EDI.WebHome]] format will always be 608/708 (depending on whether the target series contains one observation or a range of observations).
575
576 When converting a [[data structure definition>>doc:sdmx:Glossary.Data structure definition.WebHome]] originating in [[SDMX-EDI>>doc:sdmx:Glossary.SDMX-EDI.WebHome]], the [[time format>>doc:sdmx:Glossary.Time format.WebHome]] [[attribute>>doc:sdmx:Glossary.Attribute.WebHome]] should be ignored, as it serves no purpose in [[SDMX-ML>>doc:sdmx:Glossary.SDMX-ML.WebHome]].
577
578 When converting data from [[SDMX-EDI>>doc:sdmx:Glossary.SDMX-EDI.WebHome]] to [[SDMX-ML>>doc:sdmx:Glossary.SDMX-ML.WebHome]], the source [[time format>>doc:sdmx:Glossary.Time format.WebHome]] is only necessary to determine the format of the target time value. For example, a source [[time format>>doc:sdmx:Glossary.Time format.WebHome]] of will result in a target time in the format YYYY-Ss whereas a source format of will result in a target time value in the format YYYY-Qq.
579
580 === 4.2.10 Time Zones ===
581
582 In alignment with ISO 8601, [[SDMX>>doc:sdmx:Glossary.Statistical data and metadata exchange.WebHome]] allows the specification of a time zone on all [[time periods>>doc:sdmx:Glossary.Time period.WebHome]] and on the reporting year start day. If a time zone is provided on a reporting year start day, then the same time zone (or none) should be reported for each reporting [[time period>>doc:sdmx:Glossary.Time period.WebHome]]. If the reporting year start day and the reporting period time zone differ, the time zone of the reporting period will take precedence. Examples of each format with time zones are as follows (time zone indicated in bold):
583
584 * Time Range (start date): 2006-06-05**-05:00**/P5D
585 * Time Range (start date-time): 2006-06-05T00:00:00**-05:00**/P5D
586 * Gregorian Year: 2006**-05:00**
587 * Gregorian Month: 2006-06**-05:00**
588 * Gregorian Day: 2006-06-05**-05:00**
589 * Distinct Point: 2006-06-05T00:00:00**-05:00**
590 * Reporting Year: 2006-A1**-05:00**
591 * Reporting Semester: 2006-S2**-05:00**
592 * Reporting Trimester: 2006-T2**-05:00**
593 * Reporting Quarter: 2006-Q3**-05:00**
594 * Reporting Month: 2006-M06**-05:00**
595 * Reporting Week: 2006-W23**-05:00**
596 * Reporting Day: 2006-D156**-05:00**
597 * Reporting Year Start Day: 07-01**-05:00**
598
599 According to ISO 8601, a date without a time-zone is considered "local time". [[SDMX>>doc:sdmx:Glossary.Statistical data and metadata exchange.WebHome]] assumes that local time is that of the sender of the message. In this (% style="color:#e74c3c" %)version(%%) of [[SDMX>>doc:sdmx:Glossary.Statistical data and metadata exchange.WebHome]], an optional field is added to the sender definition in the header for specifying a time zone. This field has a default value of 'Z' (UTC). This determination of local time applies for all dates in a message.
600
601 === 4.2.11 Representing Time Spans Elsewhere ===
602
603 It has been possible since [[SDMX>>doc:sdmx:Glossary.Statistical data and metadata exchange.WebHome]] 2.0 for a [[Component>>doc:sdmx:Glossary.Component.WebHome]] to specify a [[representation>>doc:sdmx:Glossary.Representation.WebHome]] of a time span. Depending on the format of the data message, this resulted in either an element with 2 XML [[attributes>>doc:sdmx:Glossary.Attribute.WebHome]] for holding the start time and the duration or two separate XML [[attributes>>doc:sdmx:Glossary.Attribute.WebHome]] based on the underlying [[Component>>doc:sdmx:Glossary.Component.WebHome]] identifier. For example if REF_PERIOD were given a [[representation>>doc:sdmx:Glossary.Representation.WebHome]] of time span, then in the Compact data format, it would be represented by two XML [[attributes>>doc:sdmx:Glossary.Attribute.WebHome]]; REF_PERIODStartTime (holding the start) and REF_PERIOD (holding the duration). If a new simple type is introduced in the [[SDMX>>doc:sdmx:Glossary.Statistical data and metadata exchange.WebHome]] schemas that can hold ISO 8601 time intervals, then this will no longer be necessary. What was represented as this:
604
605 <Series REF_PERIODStartTime="2000-01-01T00:00:00" REF_PERIOD="P2M"/>
606
607 can now be represented with this:
608
609 <Series REF_PERIOD="2000-01-01T00:00:00/P2M"/>
610
611 === 4.2.12 Notes on Formats ===
612
613 There is no ambiguity in these formats so that for any given value of time, the [[category>>doc:sdmx:Glossary.Category.WebHome]] of the period (and thus the intended [[time period>>doc:sdmx:Glossary.Time period.WebHome]] range) is always clear. It should also be noted that by utilizing the ISO 8601 format, and a format loosely based on it for the report periods, the values of time can easily be sorted chronologically without additional parsing.
614
615 === 4.2.13 Effect on Time Ranges ===
616
617 All [[SDMX-ML>>doc:sdmx:Glossary.SDMX-ML.WebHome]] data messages are capable of functioning in a manner similar to [[SDMX-EDI>>doc:sdmx:Glossary.SDMX-EDI.WebHome]] if the [[Dimension>>doc:sdmx:Glossary.Dimension.WebHome]] at the observation (% style="color:#e74c3c" %)level(%%) is time: the [[time period>>doc:sdmx:Glossary.Time period.WebHome]] for the first observation can be stated and the rest of the observations can omit the time value as it can be derived from the start time and the frequency. Since the frequency can be determined based on the actual format of the time value for everything but distinct points in time and time ranges, this makes is even simpler to process as the interval between time ranges is known directly from the time value.
618
619 === 4.2.14 Time in Query Messages ===
620
621 When querying for time values, the value of a time parameter can be provided as any of the Observational [[Time Period>>doc:sdmx:Glossary.Time period.WebHome]] formats and must be paired with an operator. In addition, an explicit value for the reporting year start day can be provided, or this can be set to "Any". This section will detail how systems processing query messages should interpret these parameters.
622
623 Fundamental to processing a time value parameter in a query message is understanding that all [[time periods>>doc:sdmx:Glossary.Time period.WebHome]] should be handled as a distinct range of time. Since the time parameter in the query is paired with an operator, this is also effectively represents a distinct range of time. Therefore, a system processing the query must simply match the data where the [[time period>>doc:sdmx:Glossary.Time period.WebHome]] for requested parameter is encompassed by the [[time period>>doc:sdmx:Glossary.Time period.WebHome]] resulting from value of the query parameter. The following table details how the operators should be interpreted for any [[time period>>doc:sdmx:Glossary.Time period.WebHome]] provided as a parameter.
624
625 (% style="width:1024.29px" %)
626 |(% style="width:238px" %)**Operator**|(% style="width:782px" %)**Rule**
627 |(% style="width:238px" %)Greater Than|(% style="width:782px" %)Any data after the last moment of the period
628 |(% style="width:238px" %)Less Than|(% style="width:782px" %)Any data before the first moment of the period
629 |(% style="width:238px" %)Greater Than or Equal To|(% style="width:782px" %)(((
630 Any data on or after the first moment of the period
631 )))
632 |(% style="width:238px" %)Less Than or Equal To|(% style="width:782px" %)Any data on or before the last moment of the period
633 |(% style="width:238px" %)Equal To|(% style="width:782px" %)Any data which falls on or after the first moment of the period and before or on the last moment of the period
634
635 Reporting [[Time Periods>>doc:sdmx:Glossary.Time period.WebHome]] as query parameters are handled based on whether the value of the reportingYearStartDay XML [[attribute>>doc:sdmx:Glossary.Attribute.WebHome]] is an explicit month and day or "Any":
636
637 If the time parameter provides an explicit month and day value for the reportingYearStartDay XML [[attribute>>doc:sdmx:Glossary.Attribute.WebHome]], then the parameter value is converted to a distinct range and processed as any other [[time period>>doc:sdmx:Glossary.Time period.WebHome]] would be processed.
638
639 If the reportingYeartStartDay XML [[attribute>>doc:sdmx:Glossary.Attribute.WebHome]] has a value of "Any", then any data within the bounds of the reporting period for the year is matched, regardless of the actual start day of the reporting year. In addition, data reported against a normal calendar period is matched if it falls within the bounds of the time parameter based on a reporting year start day of January 1. When determining whether another reporting period falls within the bounds of a report period query parameter, one will have to take into account the actual [[time period>>doc:sdmx:Glossary.Time period.WebHome]] to compare weeks and days to higher order report periods. This will be demonstrated in the examples to follow.
640
641 Note that the reportingYearStartDay XML [[attribute>>doc:sdmx:Glossary.Attribute.WebHome]] on the time value parameter is only used to qualify a reporting period value for the given time value parameter. The usage of this is different than using the [[attribute>>doc:sdmx:Glossary.Attribute.WebHome]] value parameter for the actual reporting year start day [[attribute>>doc:sdmx:Glossary.Attribute.WebHome]]. In the case that the [[attribute>>doc:sdmx:Glossary.Attribute.WebHome]] value parameters is used for the reporting year start day data structure [[attribute>>doc:sdmx:Glossary.Attribute.WebHome]], it will be treated as any other [[attribute>>doc:sdmx:Glossary.Attribute.WebHome]] value parameter; data will be filtered to that which matches the values specified for the given [[attribute>>doc:sdmx:Glossary.Attribute.WebHome]]. For example, if the [[attribute>>doc:sdmx:Glossary.Attribute.WebHome]] value parameter references the reporting year start day [[attribute>>doc:sdmx:Glossary.Attribute.WebHome]] and specifies a value of "07-01", then only data which has this [[attribute>>doc:sdmx:Glossary.Attribute.WebHome]] with the value "07-01" will be returned. In terms of processing any time value parameters, the value supplied in the [[attribute>>doc:sdmx:Glossary.Attribute.WebHome]] value parameter will be irrelevant.
642
643 **Examples:**
644
645 **Gregorian Period**
646 Query Parameter: Greater than 2010
647 Literal Interpretation: Any data where the start period occurs after 2010-1231T23:59:59.
648
649 Example Matches:
650
651 * 2011 or later
652 * 2011-01 or later
653 * 2011-01-01 or later
654 * 2011-01-01/P[Any Duration] or any later start date
655 * 2011-[Any reporting period] (any reporting year start day)
656 * 2010-S2 (reporting year start day ~-~-07-01 or later)
657 * 2010-T3 (reporting year start day ~-~-07-01 or later)
658 * 2010-Q3 or later (reporting year start day ~-~-07-01 or later)
659 * 2010-M07 or later (reporting year start day ~-~-07-01 or later)
660 * 2010-W28 or later (reporting year start day ~-~-07-01 or later)
661 * 2010-D185 or later (reporting year start day ~-~-07-01 or later)
662
663 **Reporting Period with explicit start day**
664
665 Query Parameter: Greater than or equal to 2009-Q3, reporting year start day = "-07-01"
666 Literal Interpretation: Any data where the start period occurs on after 2010-0101T00:00:00 (Note that in this case 2009-Q3 is converted to the explicit date range of 2010-01-01/2010-03-31 because of the reporting year start day value). Example Matches: Same as previous example
667
668 **Reporting Period with "Any" start day**
669 Query Parameter: Greater than or equal to 2010-Q3, reporting year start day = "Any"
670 Literal Interpretation: Any data with a reporting period where the start period is on or after the start period of 2010-Q3 for the same reporting year start day, or and data where the start period is on or after 2010-07-01. Example Matches:
671
672 * 2011 or later
673 * 2010-07 or later
674 * 2010-07-01 or later
675 * 2010-07-01/P[Any Duration] or any later start date
676 * 2011-[Any reporting period] (any reporting year start day)
677 * 2010-S2 (any reporting year start day)
678 * 2010-T3 (any reporting year start day)
679 * 2010-Q3 or later (any reporting year start day)
680 * 2010-M07 or later (any reporting year start day)
681 * 2010-W27 or later (reporting year start day ~-~-01-01){{footnote}}2010-Q3 (with a reporting year start day of --01-01) starts on 2010-07-01. This is day 4 of week 26, therefore the first week matched is week 27.{{/footnote}}
682 * 2010-D182 or later (reporting year start day ~-~-01-01)
683 * 2010-W28 or later (reporting year start day ~-~-07-01){{footnote}}2010-Q3 (with a reporting year start day of --07-01) starts on 2011-01-01. This is day 6 of week 27, therefore the first week matched is week 28.{{/footnote}}
684 * 2010-D185 or later (reporting year start day ~-~-07-01)
685
686 == 4.3 Structural Metadata Querying Best Practices ==
687
688 When querying for [[structural metadata>>doc:sdmx:Glossary.Structural metadata.WebHome]], the ability to state how references should be resolved is quite powerful. However, this mechanism is not always necessary and can create an undue burden on the systems processing the queries if it is not used properly.
689
690 Any [[structural metadata>>doc:sdmx:Glossary.Structural metadata.WebHome]] object which contains a reference to an object can be queried based on that reference. For example, a categorisation references both a [[category>>doc:sdmx:Glossary.Category.WebHome]] and the object is it categorising. As this is the case, one can query for categorisations which categorise a particular object or which categorise against a particular [[category>>doc:sdmx:Glossary.Category.WebHome]] or [[category scheme>>doc:sdmx:Glossary.Category scheme.WebHome]]. This mechanism should be used when the referenced object is known.
691
692 When the referenced object is not known, then the reference resolution mechanism could be used. For example, suppose one wanted to find all [[category schemes>>doc:sdmx:Glossary.Category scheme.WebHome]] and the related categorisations for a given [[maintenance agency>>doc:sdmx:Glossary.Maintenance agency.WebHome]]. In this case, one could query for the [[category scheme>>doc:sdmx:Glossary.Category scheme.WebHome]] by the [[maintenance agency>>doc:sdmx:Glossary.Maintenance agency.WebHome]] and specify that parent and sibling references should be resolved. This would result in the categorisations which reference the [[categories>>doc:sdmx:Glossary.Category.WebHome]] in the matched schemes to be returned, as well as the object which they categorise.
693
694 == 4.4 Versioning and External Referencing ==
695
696 Within the [[SDMX-ML>>doc:sdmx:Glossary.SDMX-ML.WebHome]] Structure Message, there is a pattern for versioning and external referencing which should be pointed out. The identifiers are qualified by their (% style="color:#e74c3c" %)version(%%) numbers – that is, an object with an Agency of “A”, and ID of “X” and a (% style="color:#e74c3c" %)version(%%) of “1.0” is a different object than one with an Agency of “A’, an ID of “X”, and a (% style="color:#e74c3c" %)version(%%) of “1.1”.
697
698 The production (% style="color:#e74c3c" %)versions(%%) of identifiable objects/resources are assumed to be static – that is, they have their isFinal [[attribute>>doc:sdmx:Glossary.Attribute.WebHome]] set to ‘true”. Once in production, and object cannot change in any way, or it must be versioned. For cases where an object is not static, the isFinal [[attribute>>doc:sdmx:Glossary.Attribute.WebHome]] must have a value of “false”, but non-final objects should not be used outside of a specific system designed to accommodate them. For most purposes, all objects should be declared final before use in production.
699
700 This mechanism is an “early binding” one – everything with a versioned identity is a known quantity, and will not change. It is worth pointing out that in some cases relationships are essentially one-way references: an illustrative case is that of [[Categories>>doc:sdmx:Glossary.Category.WebHome]]. While a [[Category>>doc:sdmx:Glossary.Category.WebHome]] may be referenced by many [[dataflows>>doc:sdmx:Glossary.Dataflow.WebHome]] and [[metadata flows>>doc:sdmx:Glossary.Metadataflow.WebHome]], the addition of more references from flow objects does not (% style="color:#e74c3c" %)version(%%) the [[Category>>doc:sdmx:Glossary.Category.WebHome]]. This is because the flows are not properties of the [[Categories>>doc:sdmx:Glossary.Category.WebHome]] – they merely make references to it. If the name of a [[Category>>doc:sdmx:Glossary.Category.WebHome]] changed, or its subCategories changed, then versioning would be necessary.
701
702 Versioning operates at the (% style="color:#e74c3c" %)level(%%) of versionable and maintainable objects in the [[SDMX information model>>doc:sdmx:Glossary.SDMX Information Model.WebHome]]. If any of the children of objects at these (% style="color:#e74c3c" %)levels(%%) change, then the objects themselves are versioned.
703
704 One area which is much impacted by this versioning scheme is the ability to reference external objects. With the many dependencies within the various structural objects in [[SDMX>>doc:sdmx:Glossary.Statistical data and metadata exchange.WebHome]], it is useful to have a scheme for external referencing. This is done at the (% style="color:#e74c3c" %)level(%%) of maintainable objects (DSDs, [[code lists>>doc:sdmx:Glossary.Code list.WebHome]], [[concept schemes>>doc:sdmx:Glossary.Concept scheme.WebHome]], etc.) In an [[SDMX-ML>>doc:sdmx:Glossary.SDMX-ML.WebHome]] Structure Message, whenever an “[[isExternalReference>>doc:sdmx:Glossary.isExternalReference.WebHome]]” [[attribute>>doc:sdmx:Glossary.Attribute.WebHome]] is set to true, then the application must resolve the address provided in the associated “uri” [[attribute>>doc:sdmx:Glossary.Attribute.WebHome]] and use the [[SDMX-ML>>doc:sdmx:Glossary.SDMX-ML.WebHome]] Structure Message stored at that location for the full definition of the object in question. Alternately, if a registry “urn” [[attribute>>doc:sdmx:Glossary.Attribute.WebHome]] has been provided, the registry can be used to supply the full details of the object.
705
706 Because the (% style="color:#e74c3c" %)version(%%) number is part of the identifier for an object, (% style="color:#e74c3c" %)versions(%%) are a necessary part of determining that a given resource is the one which was called for. It should be noted that whenever a (% style="color:#e74c3c" %)version(%%) number is not supplied, it is assumed to be “1.0”. (The “x.x” versioning notation is conventional in practice with [[SDMX>>doc:sdmx:Glossary.Statistical data and metadata exchange.WebHome]], but not required.)
707
708 = 5 Metadata Structure Definition (MSD) =
709
710 == 5.1 Scope ==
711
712 The scope of the [[MSD>>doc:sdmx:Glossary.Metadata structure definition.WebHome]] is enhanced in this (% style="color:#e74c3c" %)version(%%) to better support the types of construct to which metadata can be attached. In particular it is possible to specify an attachment to any key or partial key of a [[data set>>doc:sdmx:Glossary.Data set.WebHome]]. This is particularly useful for web dissemination where metadata may be present for the data, but is not stored with the data but is related to it. For this use case to be supported it is necessary to be able to specify in the [[MSD>>doc:sdmx:Glossary.Metadata structure definition.WebHome]] that metadata is attached to a key or partial key, and the actual key or partial key to be identified in the [[Metadata Set>>doc:sdmx:Glossary.Metadata set.WebHome]].
713
714 In addition to the increase in the scope of objects that can be included in an [[MSD>>doc:sdmx:Glossary.Metadata structure definition.WebHome]], the way the identifier mechanism works in this (% style="color:#e74c3c" %)version(%%), and the terminology used, is much simpler.
715
716 == 5.2 Identification of the Object Type to which the Metadata is to be Attached ==
717
718 The following example shows the structure and naming of the [[MSD>>doc:sdmx:Glossary.Metadata structure definition.WebHome]] [[components>>doc:sdmx:Glossary.Component.WebHome]] for the use case of defining full and partial keys.
719
720 The schematic structure of an [[MSD>>doc:sdmx:Glossary.Metadata structure definition.WebHome]] is shown below.
721
722 [[image:1747836776649-282.jpeg]]
723
724 **Figure 1: Schematic of the Metadata Structure Definition**
725
726 The [[MSD>>doc:sdmx:Glossary.Metadata structure definition.WebHome]] comprises the specification of the object types to which metadata can be reported in a [[Metadata Set>>doc:sdmx:Glossary.Metadata set.WebHome]] (Metadata Target(s)), and the Report Structure(s) comprising the Metadata [[Attributes>>doc:sdmx:Glossary.Attribute.WebHome]] that identify the (% style="color:#e74c3c" %)Concept(%%) for which metadata may be reported in the [[Metadata Set>>doc:sdmx:Glossary.Metadata set.WebHome]]. Importantly, one Report Structure references the Metadata Target for which it is relevant. One Report Structure can reference many Metadata Target i.e. the same Report Structure can be used for different target objects.
727
728 [[image:1747836776655-364.jpeg]]
729
730 **Figure 2: Example [[MSD>>doc:sdmx:Glossary.Metadata structure definition.WebHome]] showing Metadata Targets**
731
732 Note that the [[SDMX-ML>>doc:sdmx:Glossary.SDMX-ML.WebHome]] schemas have explicit XML elements for each identifiable object type because identifying, for instance, a Maintainable Object has different properties from an Identifiable Object which must also include the agencyId, (% style="color:#e74c3c" %)version(%%), and id of the Maintainable Object in which it resides.
733
734 == 5.3 Report Structure ==
735
736 An example is shown below.
737
738 [[image:1747836776658-510.jpeg]]
739
740 **Figure 3: Example MSD showing specification of three Metadata Attributes**
741
742 This example shows the following [[hierarchy>>doc:sdmx:Glossary.Hierarchy.WebHome]] of Metadata [[Attributes>>doc:sdmx:Glossary.Attribute.WebHome]]:
743
744 Source – this is presentational and no metadata is expected to be reported at this (% style="color:#e74c3c" %)level
745
746 * Source Type
747 * Collection Source Name
748
749 == 5.4 Metadata Set ==
750
751 An example of reporting metadata according to the [[MSD>>doc:sdmx:Glossary.Metadata structure definition.WebHome]] described above, is shown below.
752
753 [[image:1747836776677-246.jpeg]]
754
755 **Figure 4: Example Metadata Set **This example shows:
756
757 1. The reference to the [[MSD>>doc:sdmx:Glossary.Metadata structure definition.WebHome]], Metadata Report, and Metadata Target (MetadataTargetValue)
758 1. The reported metadata [[attributes>>doc:sdmx:Glossary.Attribute.WebHome]] (AttributeValueSet)
759
760 = 6 Maintenance Agencies =
761
762 All [[structural metadata>>doc:sdmx:Glossary.Structural metadata.WebHome]] in [[SDMX>>doc:sdmx:Glossary.Statistical data and metadata exchange.WebHome]] is owned and maintained by a [[maintenance agency>>doc:sdmx:Glossary.Maintenance agency.WebHome]] (Agency identified by agencyID in the schemas). It is vital to the integrity of the [[structural metadata>>doc:sdmx:Glossary.Structural metadata.WebHome]] that there are no conflicts in agencyID. In order to achieve this [[SDMX>>doc:sdmx:Glossary.Statistical data and metadata exchange.WebHome]] adopts the following rules:
763
764 1. Agencies are maintained in an [[Agency Scheme>>doc:sdmx:Glossary.Agency scheme.WebHome]] (which is a sub class of Organisation Scheme)
765 1. The [[maintenance agency>>doc:sdmx:Glossary.Maintenance agency.WebHome]] of the [[Agency Scheme>>doc:sdmx:Glossary.Agency scheme.WebHome]] must also be declared in a (different) [[Agency Scheme>>doc:sdmx:Glossary.Agency scheme.WebHome]].
766 1. The “top-(% style="color:#e74c3c" %)level(%%)” agency is [[SDMX>>doc:sdmx:Glossary.Statistical data and metadata exchange.WebHome]] and this [[agency scheme>>doc:sdmx:Glossary.Agency scheme.WebHome]] is maintained by [[SDMX>>doc:sdmx:Glossary.Statistical data and metadata exchange.WebHome]].
767 1. Agencies registered in the top-(% style="color:#e74c3c" %)level(%%) scheme can themselves maintain a single [[Agency Scheme>>doc:sdmx:Glossary.Agency scheme.WebHome]]. [[SDMX>>doc:sdmx:Glossary.Statistical data and metadata exchange.WebHome]] is an agency in the [[SDMX>>doc:sdmx:Glossary.Statistical data and metadata exchange.WebHome]] [[agency scheme>>doc:sdmx:Glossary.Agency scheme.WebHome]]. Agencies in this scheme can themselves maintain a single [[Agency Scheme>>doc:sdmx:Glossary.Agency scheme.WebHome]] and so on.
768 1. The AgencyScheme cannot be versioned and so take a default (% style="color:#e74c3c" %)version(%%) number of 1.0 and cannot be made “final”.
769 1. There can be only one AgencyScheme maintained by any one Agency. It has a fixed Id of AgencyScheme.
770 1. The format of the agency identifier is agencyId.agencyID etc. The top-(% style="color:#e74c3c" %)level(%%) agency in this identification mechanism is the agency registered in the [[SDMX>>doc:sdmx:Glossary.Statistical data and metadata exchange.WebHome]] [[agency scheme>>doc:sdmx:Glossary.Agency scheme.WebHome]]. In other words, [[SDMX>>doc:sdmx:Glossary.Statistical data and metadata exchange.WebHome]] is not a part of the hierarchical ID structure for agencies. [[SDMX>>doc:sdmx:Glossary.Statistical data and metadata exchange.WebHome]] is, itself, a [[maintenance agency>>doc:sdmx:Glossary.Maintenance agency.WebHome]].
771
772 This supports a hierarchical structure of agencyID.
773
774 An example is shown below.
775
776 [[image:1747836776680-229.jpeg]]
777
778 **Figure 5: Example of Hierarchic Structure of Agencies**
779
780 Each agency is identified by its full [[hierarchy>>doc:sdmx:Glossary.Hierarchy.WebHome]] excluding [[SDMX>>doc:sdmx:Glossary.Statistical data and metadata exchange.WebHome]].
781
782 The XML representing this structure is shown below.
783
784 [[image:1747836776682-757.jpeg]]
785
786 **Figure 6: Example Agency Schemes Showing a Hierarchy**
787
788 Example of Structure Definitions:
789
790 [[image:1747836776687-934.jpeg]]
791
792 **Figure 7: Example Showing Use of Agency Identifiers**
793
794 Each of these [[maintenance agencies>>doc:sdmx:Glossary.Maintenance agency.WebHome]] has an identical Codelist with the Id CL_BOP. However, each is uniquely identified by means of the hierarchic agency structure.
795
796 = 7 Concept Roles =
797
798 == 7.1 Overview ==
799
800 The [[DSD>>doc:sdmx:Glossary.Data structure definition.WebHome]] [[Components>>doc:sdmx:Glossary.Component.WebHome]] of [[Dimension>>doc:sdmx:Glossary.Dimension.WebHome]] and [[Attribute>>doc:sdmx:Glossary.Attribute.WebHome]] can play a specific role in the [[DSD>>doc:sdmx:Glossary.Data structure definition.WebHome]] and it is important to some applications that this role is specified. For instance, the following roles are some examples:
801
802 **Frequency **– in a [[data set>>doc:sdmx:Glossary.Data set.WebHome]] the content of this [[Component>>doc:sdmx:Glossary.Component.WebHome]] contains information on the frequency of the observation values
803 **Geography** - in a [[data set>>doc:sdmx:Glossary.Data set.WebHome]] the content of this [[Component>>doc:sdmx:Glossary.Component.WebHome]] contains information on the geographic location of the observation values
804 **Unit** **of [[Measure>>doc:sdmx:Glossary.Measure.WebHome]]** - in a [[data set>>doc:sdmx:Glossary.Data set.WebHome]] the content of this [[Component>>doc:sdmx:Glossary.Component.WebHome]] contains information on the [[unit of measure>>doc:sdmx:Glossary.Unit of measure.WebHome]] of the observation values
805
806 In order for these roles to be extensible and also to enable user communities to maintain community-specific roles, the roles are maintained in a controlled vocabulary which is implemented in [[SDMX>>doc:sdmx:Glossary.Statistical data and metadata exchange.WebHome]] as (% style="color:#e74c3c" %)Concepts(%%) in a [[Concept Scheme>>doc:sdmx:Glossary.Concept scheme.WebHome]]. The [[Component>>doc:sdmx:Glossary.Component.WebHome]] optionally references this (% style="color:#e74c3c" %)Concept(%%) if it is required to declare the role explicitly. Note that a [[Component>>doc:sdmx:Glossary.Component.WebHome]] can play more than one role and therefore multiple “role” (% style="color:#e74c3c" %)concepts(%%) can be referenced.
807
808 == 7.2 Information Model ==
809
810 The Information Model for this is shown below:
811
812 [[image:1747855024745-946.png]]
813
814 **Figure 8: Information Model Extract for Concept Role**
815
816 It is possible to specify zero or more (% style="color:#e74c3c" %)concept(%%) roles for a [[Dimension>>doc:sdmx:Glossary.Dimension.WebHome]], [[Measure>>doc:sdmx:Glossary.Measure.WebHome]] [[Dimension>>doc:sdmx:Glossary.Dimension.WebHome]] and Data [[Attribute>>doc:sdmx:Glossary.Attribute.WebHome]] (but not the ReportingYearStartDay). The Time [[Dimension>>doc:sdmx:Glossary.Dimension.WebHome]], Primary [[Measure>>doc:sdmx:Glossary.Measure.WebHome]], and the [[Attribute>>doc:sdmx:Glossary.Attribute.WebHome]] ReportingYearStartDay have explicitly defined roles and cannot be further specified with additional (% style="color:#e74c3c" %)concept(%%) roles.
817
818 == 7.3 Technical Mechanism ==
819
820 The mechanism for maintain and using (% style="color:#e74c3c" %)concept(%%) roles is as follows:
821
822 1. Any recognized Agency can have a [[concept scheme>>doc:sdmx:Glossary.Concept scheme.WebHome]] that contains (% style="color:#e74c3c" %)concepts(%%) that identify (% style="color:#e74c3c" %)concept(%%) roles. Indeed, from a technical perspective any agency can have more than one of these schemes, though this is not recommended.
823 1. The [[concept scheme>>doc:sdmx:Glossary.Concept scheme.WebHome]] that contains the “role” (% style="color:#e74c3c" %)concepts(%%) can contain (% style="color:#e74c3c" %)concepts(%%) that do not play a role.
824 1. There is no explicit indication on the (% style="color:#e74c3c" %)Concept(%%) whether it is a ‘role” (% style="color:#e74c3c" %)concept(%%).
825 1. Therefore, any (% style="color:#e74c3c" %)concept(%%) in any [[concept scheme>>doc:sdmx:Glossary.Concept scheme.WebHome]] is capable of being a “role” (% style="color:#e74c3c" %)concept(%%).
826 1. It is the responsibility of Agencies to ensure their community knows which (% style="color:#e74c3c" %)concepts(%%) in which [[concept schemes>>doc:sdmx:Glossary.Concept scheme.WebHome]] play a “role” and the significance and interpretation of this role. In other words, such (% style="color:#e74c3c" %)concepts(%%) must be known by applications, there is no technical mechanism that can inform an application on how to process such a “role”.
827 1. If the (% style="color:#e74c3c" %)concept(%%) referenced in the (% style="color:#e74c3c" %)Concept(%%) Identity in a [[DSD>>doc:sdmx:Glossary.Data structure definition.WebHome]] [[component>>doc:sdmx:Glossary.Component.WebHome]] ([[Dimension>>doc:sdmx:Glossary.Dimension.WebHome]], [[Measure>>doc:sdmx:Glossary.Measure.WebHome]] [[Dimension>>doc:sdmx:Glossary.Dimension.WebHome]], [[Attribute>>doc:sdmx:Glossary.Attribute.WebHome]]) is contained in the [[concept scheme>>doc:sdmx:Glossary.Concept scheme.WebHome]] containing (% style="color:#e74c3c" %)concept(%%) roles then the [[DSD>>doc:sdmx:Glossary.Data structure definition.WebHome]] [[component>>doc:sdmx:Glossary.Component.WebHome]] could play the role implied by the (% style="color:#e74c3c" %)concept(%%), if this is understood by the processing application.
828 1. If the (% style="color:#e74c3c" %)concept(%%) referenced in the (% style="color:#e74c3c" %)Concept(%%) Identity in a [[DSD>>doc:sdmx:Glossary.Data structure definition.WebHome]] [[component>>doc:sdmx:Glossary.Component.WebHome]] ([[Dimension>>doc:sdmx:Glossary.Dimension.WebHome]], [[Measure>>doc:sdmx:Glossary.Measure.WebHome]] [[Dimension>>doc:sdmx:Glossary.Dimension.WebHome]], [[Attribute>>doc:sdmx:Glossary.Attribute.WebHome]]) is not contained in the [[concept scheme>>doc:sdmx:Glossary.Concept scheme.WebHome]] containing (% style="color:#e74c3c" %)concept(%%) roles, and the [[DSD>>doc:sdmx:Glossary.Data structure definition.WebHome]] [[component>>doc:sdmx:Glossary.Component.WebHome]] is playing a role, then the (% style="color:#e74c3c" %)concept(%%) role is identified by the (% style="color:#e74c3c" %)Concept(%%) Role in the schema.
829
830 == 7.4 SDMX-ML Examples in a DSD ==
831
832 The [[Cross-Domain Concept>>doc:sdmx:Glossary.Cross-domain concept.WebHome]] Scheme maintained by [[SDMX>>doc:sdmx:Glossary.Statistical data and metadata exchange.WebHome]] contains (% style="color:#e74c3c" %)concept(%%) role (% style="color:#e74c3c" %)concepts(%%) (FREQ chosen as an example).
833
834 [[image:1747855054559-410.png]]
835
836 Whether this is a role or not depends upon the application understanding that FREQ in the [[Cross-Domain Concept>>doc:sdmx:Glossary.Cross-domain concept.WebHome]] Scheme is a role of Frequency.
837
838 Using a [[Concept Scheme>>doc:sdmx:Glossary.Concept scheme.WebHome]] that is not the [[Cross-Domain Concept>>doc:sdmx:Glossary.Cross-domain concept.WebHome]] Scheme where it is required to assign a role using the [[Cross-Domain Concept>>doc:sdmx:Glossary.Cross-domain concept.WebHome]] Scheme. Again FREQ is chosen as the example.
839
840 [[image:1747855075263-887.png]]
841
842 This explicitly states that this [[Dimension>>doc:sdmx:Glossary.Dimension.WebHome]] is playing a role identified by the FREQ (% style="color:#e74c3c" %)concept(%%) in the [[Cross-Domain Concept>>doc:sdmx:Glossary.Cross-domain concept.WebHome]] Scheme. Again the application needs to understand what FREQ in the [[Cross-Domain Concept>>doc:sdmx:Glossary.Cross-domain concept.WebHome]] Scheme implies in terms of a role.
843
844 This is all that is required for interoperability within a community. The important point is that a community must recognise a specific Agency as having the authority to define (% style="color:#e74c3c" %)concept(%%) roles and to maintain these “role” (% style="color:#e74c3c" %)concepts(%%) in a [[concept scheme>>doc:sdmx:Glossary.Concept scheme.WebHome]] together with documentation on the meaning of the role and any relevant processing implications. This will then ensure there is interoperability between systems that understand the use of these (% style="color:#e74c3c" %)concepts(%%).
845
846 Note that each of the [[Components>>doc:sdmx:Glossary.Component.WebHome]] (Data [[Attribute>>doc:sdmx:Glossary.Attribute.WebHome]], Primary [[Measure>>doc:sdmx:Glossary.Measure.WebHome]], [[Dimension>>doc:sdmx:Glossary.Dimension.WebHome]], [[Measure>>doc:sdmx:Glossary.Measure.WebHome]] [[Dimension>>doc:sdmx:Glossary.Dimension.WebHome]], Time [[Dimension>>doc:sdmx:Glossary.Dimension.WebHome]]) has a mandatory identity association ((% style="color:#e74c3c" %)Concept(%%) Identity) and if this (% style="color:#e74c3c" %)Concept(%%) also identifies the role then it is possible to state this by
847
848 == 7.5 SDMX Cross Domain Concept Scheme ==
849
850 All (% style="color:#e74c3c" %)concepts(%%) in the [[SDMX>>doc:sdmx:Glossary.Statistical data and metadata exchange.WebHome]] Cross Domain [[Concept Scheme>>doc:sdmx:Glossary.Concept scheme.WebHome]] are capable of playing a role and this scheme will contain all of the roles that were allowed at (% style="color:#e74c3c" %)version(%%) 2.0 and will be maintained with new roles that are agreed at the (% style="color:#e74c3c" %)level(%%) of the community using the Cross Domain [[Concept Scheme>>doc:sdmx:Glossary.Concept scheme.WebHome]].
851
852 The table below lists the (% style="color:#e74c3c" %)Concepts(%%) that need to be in this scheme either for compatibility with (% style="color:#e74c3c" %)version(%%) 2.0 or because of requests for additional roles at (% style="color:#e74c3c" %)version(%%) 2.1 which have been accepted.
853
854 Note that each of the [[Components>>doc:sdmx:Glossary.Component.WebHome]] (Data [[Attribute>>doc:sdmx:Glossary.Attribute.WebHome]], Primary [[Measure>>doc:sdmx:Glossary.Measure.WebHome]], [[Dimension>>doc:sdmx:Glossary.Dimension.WebHome]], [[Measure>>doc:sdmx:Glossary.Measure.WebHome]] [[Dimension>>doc:sdmx:Glossary.Dimension.WebHome]], Time [[Dimension>>doc:sdmx:Glossary.Dimension.WebHome]]) has a mandatory identity association ((% style="color:#e74c3c" %)Concept(%%) Identity) and if this (% style="color:#e74c3c" %)Concept(%%) also identifies the role then it is possible to state this by means of the isRole [[attribute>>doc:sdmx:Glossary.Attribute.WebHome]] (isRole=true) Additional roles can still be specified by means of the +role association to additional (% style="color:#e74c3c" %)Concepts(%%) that identify the role.
855
856 = 8 Constraints =
857
858 == 8.1 Introduction ==
859
860 In this (% style="color:#e74c3c" %)version(%%) of [[SDMX>>doc:sdmx:Glossary.Statistical data and metadata exchange.WebHome]] the (% style="color:#e74c3c" %)Constraints(%%) is a [[Maintainable Artefact>>doc:sdmx:Glossary.Maintainable artefact.WebHome]] can be associated to one or more of:
861
862 * Data Structure Definition
863 * [[Metadata Structure Definition>>doc:sdmx:Glossary.Metadata structure definition.WebHome]]
864 * [[Dataflow>>doc:sdmx:Glossary.Dataflow.WebHome]]
865 * [[Metadataflow>>doc:sdmx:Glossary.Metadataflow.WebHome]]
866 * [[Provision Agreement>>doc:sdmx:Glossary.Provision agreement.WebHome]]
867 * [[Data Provider>>doc:sdmx:Glossary.Data provider.WebHome]] (this is restricted to a [[Release Calendar>>doc:sdmx:Glossary.Release policy - release calendar.WebHome]] (% style="color:#e74c3c" %)Constraint(%%))
868 * Simple or Queryable Datasources
869
870 Note that regardless of the artifact to which the (% style="color:#e74c3c" %)Constraint(%%) is associated, it is constraining the contents of [[code lists>>doc:sdmx:Glossary.Code list.WebHome]] in the [[DSD>>doc:sdmx:Glossary.Data structure definition.WebHome]] to which the constrained object is related. This does not apply, of course, to a [[Data Provider>>doc:sdmx:Glossary.Data provider.WebHome]] as the [[Data Provider>>doc:sdmx:Glossary.Data provider.WebHome]] can be associated, via the [[Provision Agreement>>doc:sdmx:Glossary.Provision agreement.WebHome]], to many DSDs. Hence the reason for the restriction on the type of (% style="color:#e74c3c" %)Constraint(%%) that can be attached to a [[Data Provider>>doc:sdmx:Glossary.Data provider.WebHome]].
871
872 == 8.2 Types of Constraint ==
873
874 The (% style="color:#e74c3c" %)Constraint(%%) can be of one of two types:
875
876 * Content (% style="color:#e74c3c" %)constraint
877 * Attachable (% style="color:#e74c3c" %)constraint
878
879 The attachable (% style="color:#e74c3c" %)constraint(%%) is used to define “cube slices” which identify sub sets of data in terms of [[series keys>>doc:sdmx:Glossary.Series key.WebHome]] or [[dimension>>doc:sdmx:Glossary.Dimension.WebHome]] values. The purpose of this is to enable metadata to be attached to the (% style="color:#e74c3c" %)constraint(%%), and thereby to the cube slices defined in the (% style="color:#e74c3c" %)Constraint(%%). The metadata can be attached via the “[[reference metadata>>doc:sdmx:Glossary.Reference metadata.WebHome]]” mechanism – [[MSD>>doc:sdmx:Glossary.Metadata structure definition.WebHome]] and [[Metadata Set>>doc:sdmx:Glossary.Metadata set.WebHome]] – or via a Group in the [[DSD>>doc:sdmx:Glossary.Data structure definition.WebHome]]. Below is snippet of the schema for a [[DSD>>doc:sdmx:Glossary.Data structure definition.WebHome]] that shows the constructs that enable the (% style="color:#e74c3c" %)Constraint(%%) to referenced from a Group in a [[DSD>>doc:sdmx:Glossary.Data structure definition.WebHome]].
880
881 [[image:1747836776695-806.jpeg]]
882
883 **Figure 9: Extract from the SDMX-ML Schema showing reference to Attachment Constraint**
884
885 For the Content (% style="color:#e74c3c" %)Constraint(%%) specific “inheritance” rules apply and these are detailed below.
886
887 == 8.3 Rules for a Content Constraint ==
888
889 === 8.3.1 Scope of a Content Constraint ===
890
891 A Content (% style="color:#e74c3c" %)Constraint(%%) is used specify the content of a data or metadata source in terms of the [[component>>doc:sdmx:Glossary.Component.WebHome]] values or the keys.
892
893 In terms of data the [[components>>doc:sdmx:Glossary.Component.WebHome]] are:
894
895 * [[Dimension>>doc:sdmx:Glossary.Dimension.WebHome]]
896 * [[Measure>>doc:sdmx:Glossary.Measure.WebHome]] [[Dimension>>doc:sdmx:Glossary.Dimension.WebHome]]
897 * Time [[Dimension>>doc:sdmx:Glossary.Dimension.WebHome]]
898 * Data [[Attribute>>doc:sdmx:Glossary.Attribute.WebHome]]
899 * Primary [[Measure>>doc:sdmx:Glossary.Measure.WebHome]]
900
901 And the keys are the content of the KeyDescriptor – i.e. the [[series keys>>doc:sdmx:Glossary.Series key.WebHome]] composed, for each key, by a value for each [[Dimension>>doc:sdmx:Glossary.Dimension.WebHome]] and [[Measure>>doc:sdmx:Glossary.Measure.WebHome]] [[Dimension>>doc:sdmx:Glossary.Dimension.WebHome]]
902
903 In terms of [[reference metadata>>doc:sdmx:Glossary.Reference metadata.WebHome]] the [[components>>doc:sdmx:Glossary.Component.WebHome]] are:
904
905 * Target Object which is one of:
906 ** Key Descriptor Values o [[Data Set>>doc:sdmx:Glossary.Data set.WebHome]] o Report Period
907 ** IdentifiableObject
908 * Metadata [[Attribute>>doc:sdmx:Glossary.Attribute.WebHome]]
909
910 The “key” is therefore the combination of the Target Objects that are defined for the Metadata Target.
911
912 For a (% style="color:#e74c3c" %)Constraint(%%) based on a [[DSD>>doc:sdmx:Glossary.Data structure definition.WebHome]] the Content (% style="color:#e74c3c" %)Constraint(%%) can reference one or more of:
913
914 * Data Structure Definition
915 * [[Dataflow>>doc:sdmx:Glossary.Dataflow.WebHome]]
916 * [[Provision Agreement>>doc:sdmx:Glossary.Provision agreement.WebHome]]
917
918 For a (% style="color:#e74c3c" %)Constraint(%%) based on an [[MSD>>doc:sdmx:Glossary.Metadata structure definition.WebHome]] the Content (% style="color:#e74c3c" %)Constraint(%%) can reference one or more of:
919
920 * [[Metadata Structure Definition>>doc:sdmx:Glossary.Metadata structure definition.WebHome]]
921 * [[Metadataflow>>doc:sdmx:Glossary.Metadataflow.WebHome]]
922 * [[Provision Agreement>>doc:sdmx:Glossary.Provision agreement.WebHome]]
923
924 Furthermore, there can be more than one Content (% style="color:#e74c3c" %)Constraint(%%) specified for a specific object e.g. more than one (% style="color:#e74c3c" %)Constraint(%%) for a specific [[DSD>>doc:sdmx:Glossary.Data structure definition.WebHome]].
925
926 In view of the flexibility of (% style="color:#e74c3c" %)constraints(%%) attachment, clear rules on their usage are required. These are elaborated below.
927
928 === 8.3.2 Multiple Content Constraints ===
929
930 There can be many Content (% style="color:#e74c3c" %)Constraints(%%) for any Constrainable [[Artefact>>doc:sdmx:Glossary.Artefact.WebHome]] (e.g. [[DSD>>doc:sdmx:Glossary.Data structure definition.WebHome]]), subject to the following restrictions:
931
932 ==== 8.3.2.1 Cube Region ====
933
934 1. The (% style="color:#e74c3c" %)constraint(%%) can contain multiple [[Member Selections>>doc:sdmx:Glossary.Member selection.WebHome]] (e.g. [[Dimension>>doc:sdmx:Glossary.Dimension.WebHome]]) but:
935 1. A specific [[Member Selection>>doc:sdmx:Glossary.Member selection.WebHome]] (e.g. [[Dimension>>doc:sdmx:Glossary.Dimension.WebHome]] FREQ) can only be contained in one Content (% style="color:#e74c3c" %)Constraint(%%) for any one attached object (e.g. a specific [[DSD>>doc:sdmx:Glossary.Data structure definition.WebHome]] or specific [[Dataflow>>doc:sdmx:Glossary.Dataflow.WebHome]])
936
937 ==== 8.3.2.2 Key Set ====
938
939 Key Sets will be processed in the order they appear in the (% style="color:#e74c3c" %)Constraint(%%) and wildcards can be used (e.g. any key position not reference explicitly is deemed to be “all values”). As the Key Sets can be “included” or “excluded” it is recommended that Key Sets with wildcards are declared before KeySets with specific [[series keys>>doc:sdmx:Glossary.Series key.WebHome]]. This will minimize the risk that keys are inadvertently included or excluded.
940
941 === 8.3.3 Inheritance of a Content Constraint ===
942
943 ==== 8.3.3.1 Attachment levels of a Content Constraint ====
944
945 There are three (% style="color:#e74c3c" %)levels(%%) of (% style="color:#e74c3c" %)constraint(%%) attachment for which these inheritance rules apply:
946
947 * [[DSD>>doc:sdmx:Glossary.Data structure definition.WebHome]]/[[MSD>>doc:sdmx:Glossary.Metadata structure definition.WebHome]] – top (% style="color:#e74c3c" %)level
948 ** [[Dataflow>>doc:sdmx:Glossary.Dataflow.WebHome]]/[[Metadataflow>>doc:sdmx:Glossary.Metadataflow.WebHome]] – second (% style="color:#e74c3c" %)level
949 *** [[Provision Agreement>>doc:sdmx:Glossary.Provision agreement.WebHome]] – third (% style="color:#e74c3c" %)level
950
951 Note that these rules do not apply to the Simple Datasoucre or Queryable Datasource: the Content (% style="color:#e74c3c" %)Constraint(%%)(s) attached to these [[artefacts>>doc:sdmx:Glossary.Artefact.WebHome]] are resolved for this [[artefact>>doc:sdmx:Glossary.Artefact.WebHome]] only and do not take into account (% style="color:#e74c3c" %)Constraints(%%) attached to other [[artefacts>>doc:sdmx:Glossary.Artefact.WebHome]] (e.g. [[Provision Agreement>>doc:sdmx:Glossary.Provision agreement.WebHome]]. [[Dataflow>>doc:sdmx:Glossary.Dataflow.WebHome]], [[DSD>>doc:sdmx:Glossary.Data structure definition.WebHome]]).
952
953 It is not necessary for a Content (% style="color:#e74c3c" %)Constraint(%%) to be attached to higher (% style="color:#e74c3c" %)level(%%) artifact. e.g. it is valid to have a Content (% style="color:#e74c3c" %)Constraint(%%) for a [[Provision Agreement>>doc:sdmx:Glossary.Provision agreement.WebHome]] where there are no (% style="color:#e74c3c" %)constraints(%%) attached the relevant [[dataflow>>doc:sdmx:Glossary.Dataflow.WebHome]] or [[DSD>>doc:sdmx:Glossary.Data structure definition.WebHome]].
954
955 ==== 8.3.3.2 Cascade rules for processing Constraints ====
956
957 The processing of the (% style="color:#e74c3c" %)constraints(%%) on either [[Dataflow>>doc:sdmx:Glossary.Dataflow.WebHome]]/[[Metadataflow>>doc:sdmx:Glossary.Metadataflow.WebHome]] or [[Provision Agreement>>doc:sdmx:Glossary.Provision agreement.WebHome]] must take into account the (% style="color:#e74c3c" %)constraints(%%) declared at higher (% style="color:#e74c3c" %)levels(%%). The rules for the lower (% style="color:#e74c3c" %)level(%%) (% style="color:#e74c3c" %)constraints(%%) (attached to [[Dataflow>>doc:sdmx:Glossary.Dataflow.WebHome]]/ [[Metadataflow>>doc:sdmx:Glossary.Metadataflow.WebHome]] and [[Provision Agreement>>doc:sdmx:Glossary.Provision agreement.WebHome]]) are detailed below.
958
959 Note that there can be a situation where a (% style="color:#e74c3c" %)constraint(%%) is specified at a lower (% style="color:#e74c3c" %)level(%%) before a (% style="color:#e74c3c" %)constraint(%%) is specified at a higher (% style="color:#e74c3c" %)level(%%). Therefore, it is possible that a higher (% style="color:#e74c3c" %)level(%%) (% style="color:#e74c3c" %)constraint(%%) makes a lower (% style="color:#e74c3c" %)level(%%) (% style="color:#e74c3c" %)constraint(%%) invalid. [[SDMX>>doc:sdmx:Glossary.Statistical data and metadata exchange.WebHome]] makes no rules on how such a conflict should be handled when processing the (% style="color:#e74c3c" %)constraint(%%) for attachment. However, the cascade rules on evaluating (% style="color:#e74c3c" %)constraints(%%) for usage are clear - the higher (% style="color:#e74c3c" %)level(%%) (% style="color:#e74c3c" %)constraint(%%) takes precedence in any conflicts that result in a less restrictive specification at the lower (% style="color:#e74c3c" %)level(%%).
960
961 ==== 8.3.3.3 Cube Region ====
962
963 1. It is not necessary to have a (% style="color:#e74c3c" %)constraint(%%) on the higher (% style="color:#e74c3c" %)level(%%) artifact (e.g. [[DSD>>doc:sdmx:Glossary.Data structure definition.WebHome]] referenced by the [[Dataflow>>doc:sdmx:Glossary.Dataflow.WebHome]]) but if there is such a (% style="color:#e74c3c" %)constraint(%%) at the higher (% style="color:#e74c3c" %)level(%%)(s) then:
964 a. The lower (% style="color:#e74c3c" %)level(%%) (% style="color:#e74c3c" %)constraint(%%) cannot be less restrictive than the (% style="color:#e74c3c" %)constraint(%%) specified for the same [[Member Selection>>doc:sdmx:Glossary.Member selection.WebHome]] (e.g. [[Dimension>>doc:sdmx:Glossary.Dimension.WebHome]]) at the next higher (% style="color:#e74c3c" %)level(%%) which (% style="color:#e74c3c" %)constraints(%%) that [[Member Selection>>doc:sdmx:Glossary.Member selection.WebHome]] (e.g. if the [[Dimension>>doc:sdmx:Glossary.Dimension.WebHome]] FREQ is constrained to A, Q in a [[DSD>>doc:sdmx:Glossary.Data structure definition.WebHome]] then the (% style="color:#e74c3c" %)constraint(%%) at the [[Dataflow>>doc:sdmx:Glossary.Dataflow.WebHome]] or [[Provision Agreement>>doc:sdmx:Glossary.Provision agreement.WebHome]] cannot be A, Q, M or even just M – it can only further constrain A,Q).
965 b. The (% style="color:#e74c3c" %)constraint(%%) at the lower (% style="color:#e74c3c" %)level(%%) for any one [[Member Selection>>doc:sdmx:Glossary.Member selection.WebHome]] further constrains the content for the same [[Member Selection>>doc:sdmx:Glossary.Member selection.WebHome]] at the higher (% style="color:#e74c3c" %)level(%%)(s).
966 1. Any [[Member Selection>>doc:sdmx:Glossary.Member selection.WebHome]] which is not referenced in a Content (% style="color:#e74c3c" %)Constraint(%%) is deemed to be constrained according to the Content (% style="color:#e74c3c" %)Constraint(%%) specified at the next higher (% style="color:#e74c3c" %)level(%%) which (% style="color:#e74c3c" %)constraints(%%) that [[Member Selection>>doc:sdmx:Glossary.Member selection.WebHome]].
967 1. If there is a conflict when resolving the (% style="color:#e74c3c" %)constraint(%%) in terms of a lower-(% style="color:#e74c3c" %)level(%%) (% style="color:#e74c3c" %)constraint(%%) being less restrictive than a higher-(% style="color:#e74c3c" %)level(%%) (% style="color:#e74c3c" %)constraint(%%) then the (% style="color:#e74c3c" %)constraint(%%) at the higher-(% style="color:#e74c3c" %)level(%%) is used.
968
969 Note that it is possible for a Content (% style="color:#e74c3c" %)Constraint(%%) at a higher (% style="color:#e74c3c" %)level(%%) to constrain, say, four [[Dimensions>>doc:sdmx:Glossary.Dimension.WebHome]] in a single (% style="color:#e74c3c" %)constraint(%%), and a Content (% style="color:#e74c3c" %)Constraint(%%) at a lower (% style="color:#e74c3c" %)level(%%) to constrain the same four in two, three, or four Content (% style="color:#e74c3c" %)Constraints(%%).
970
971 ==== 8.3.3.4 Key Set ====
972
973 1. It is not necessary to have a (% style="color:#e74c3c" %)constraint(%%) on the higher (% style="color:#e74c3c" %)level(%%) [[artefact>>doc:sdmx:Glossary.Artefact.WebHome]] (e.g. [[DSD>>doc:sdmx:Glossary.Data structure definition.WebHome]] referenced by the [[Dataflow>>doc:sdmx:Glossary.Dataflow.WebHome]]) but if there is such a (% style="color:#e74c3c" %)constraint(%%) at the higher (% style="color:#e74c3c" %)level(%%)(s) then:
974 a. The lower (% style="color:#e74c3c" %)level(%%) (% style="color:#e74c3c" %)constraint(%%) cannot be less restrictive than the (% style="color:#e74c3c" %)constraint(%%) specified at the higher (% style="color:#e74c3c" %)level(%%).
975 b. The (% style="color:#e74c3c" %)constraint(%%) at the lower (% style="color:#e74c3c" %)level(%%) for any one [[Member Selection>>doc:sdmx:Glossary.Member selection.WebHome]] further constrains the keys specified at the higher (% style="color:#e74c3c" %)level(%%)(s).
976 1. Any [[Member Selection>>doc:sdmx:Glossary.Member selection.WebHome]] which is not referenced in a Content (% style="color:#e74c3c" %)Constraint(%%) is deemed to be constrained according to the Content (% style="color:#e74c3c" %)Constraint(%%) specified at the next higher (% style="color:#e74c3c" %)level(%%) which (% style="color:#e74c3c" %)constraints(%%) that [[Member Selection>>doc:sdmx:Glossary.Member selection.WebHome]].
977 1. If there is a conflict when resolving the keys in the (% style="color:#e74c3c" %)constraint(%%) at two (% style="color:#e74c3c" %)levels(%%), in terms of a lower-(% style="color:#e74c3c" %)level(%%) (% style="color:#e74c3c" %)constraint(%%) being less restrictive than a higher-(% style="color:#e74c3c" %)level(%%) (% style="color:#e74c3c" %)constraint(%%), then the offending keys specified at the lower (% style="color:#e74c3c" %)level(%%) are not deemed part of the (% style="color:#e74c3c" %)constraint(%%).
978
979 Note that a Key in a Key Set can have wildcarded [[Components>>doc:sdmx:Glossary.Component.WebHome]]. For instance the (% style="color:#e74c3c" %)constraint(%%) may simply constrain the [[Dimension>>doc:sdmx:Glossary.Dimension.WebHome]] FREQ to “A”, and all keys where the FREQ=A are therefore valid.
980
981 The following logic explains how the inheritance mechanism works. Note that this is conceptual logic and actual systems may differ in the way this is implemented.
982
983 1. Determine all possible keys that are valid at the higher (% style="color:#e74c3c" %)level(%%).
984 1. These keys are deemed to be inherited by the lower (% style="color:#e74c3c" %)level(%%) constrained object, subject to the (% style="color:#e74c3c" %)constraints(%%) specified at the lower (% style="color:#e74c3c" %)level(%%).
985 1. Determine all possible keys that are possible using the (% style="color:#e74c3c" %)constraints(%%) specified at the lower (% style="color:#e74c3c" %)level(%%).
986 1. At the lower (% style="color:#e74c3c" %)level(%%) inherit all keys that match with the higher (% style="color:#e74c3c" %)level(%%) (% style="color:#e74c3c" %)constraint(%%).
987 1. If there are keys in the lower (% style="color:#e74c3c" %)level(%%) (% style="color:#e74c3c" %)constraint(%%) that are not inherited then the key is invalid (i.e. it is less restrictive).
988
989 === 8.3.4 Constraints Examples ===
990
991 The following scenario is used.
992
993 __DSD__
994
995 This contains the following [[Dimensions>>doc:sdmx:Glossary.Dimension.WebHome]]:
996
997 * GEO – Geography
998 * SEX – Sex
999 * [[AGE>>doc:sdmx:Glossary.Age.WebHome]] – [[Age>>doc:sdmx:Glossary.Age.WebHome]]
1000 * CAS – Current Activity Status
1001
1002 In the [[DSD>>doc:sdmx:Glossary.Data structure definition.WebHome]] common [[code lists>>doc:sdmx:Glossary.Code list.WebHome]] are used and the requirement is to restrict these at various (% style="color:#e74c3c" %)levels(%%) to specify the actual [[code>>doc:sdmx:Glossary.Code.WebHome]] that are valid for the object to which the Content (% style="color:#e74c3c" %)Constraint(%%) is attached.
1003
1004 [[image:1747855493531-357.png]]
1005
1006 **Figure 10: Example Scenario for Constraints**
1007
1008 (% style="color:#e74c3c" %)Constraints(%%) are declared as follows:
1009
1010 [[image:1747855462293-368.png]]
1011
1012 **Figure 11: Example Content Constraints**
1013
1014 **Notes:**
1015
1016 1. [[AGE>>doc:sdmx:Glossary.Age.WebHome]] is constrained for the [[DSD>>doc:sdmx:Glossary.Data structure definition.WebHome]] and is further restricted for the [[Dataflow>>doc:sdmx:Glossary.Dataflow.WebHome]] CENSUS_CUBE1.
1017 1. The same (% style="color:#e74c3c" %)Constraint(%%) applies to both Provision Agreements.
1018
1019 The cascade rules elaborated above result as follows:
1020
1021 __DSD__
1022
1023 ~1. Constrained by eliminating [[code>>doc:sdmx:Glossary.Code.WebHome]] 001 from the [[code list>>doc:sdmx:Glossary.Code list.WebHome]] for the [[AGE>>doc:sdmx:Glossary.Age.WebHome]] [[Dimension>>doc:sdmx:Glossary.Dimension.WebHome]].
1024
1025 __Dataflow CENSUS_CUBE1__
1026
1027 1. Constrained by restricting the [[code list>>doc:sdmx:Glossary.Code list.WebHome]] for the [[AGE>>doc:sdmx:Glossary.Age.WebHome]] [[Dimension>>doc:sdmx:Glossary.Dimension.WebHome]] to [[codes>>doc:sdmx:Glossary.Code.WebHome]] 002 and 003(note that this is a more restrictive (% style="color:#e74c3c" %)constraint(%%) than that declared for the [[DSD>>doc:sdmx:Glossary.Data structure definition.WebHome]] which specifies all [[codes>>doc:sdmx:Glossary.Code.WebHome]] except [[code>>doc:sdmx:Glossary.Code.WebHome]] 001).
1028 1. Restricts the CAS [[codes>>doc:sdmx:Glossary.Code.WebHome]] to 003 and 004.
1029
1030 __Dataflow CENSUS_CUBE2__
1031
1032 1. Restricts the [[code list>>doc:sdmx:Glossary.Code list.WebHome]] for the CAS [[Dimension>>doc:sdmx:Glossary.Dimension.WebHome]] to [[codes>>doc:sdmx:Glossary.Code.WebHome]] TOT and NAP.
1033 1. Inherits the [[AGE>>doc:sdmx:Glossary.Age.WebHome]] (% style="color:#e74c3c" %)constraint(%%) applied at the (% style="color:#e74c3c" %)level(%%) of the [[DSD>>doc:sdmx:Glossary.Data structure definition.WebHome]].
1034
1035 __Provision Agreements CENSUS_CUBE1_IT__
1036
1037 1. Restricts the [[codes>>doc:sdmx:Glossary.Code.WebHome]] for the GEO [[Dimension>>doc:sdmx:Glossary.Dimension.WebHome]] to IT and its children.
1038 1. Inherits the (% style="color:#e74c3c" %)constraints(%%) from [[Dataflow>>doc:sdmx:Glossary.Dataflow.WebHome]] CENSUS_CUBE1 for the [[AGE>>doc:sdmx:Glossary.Age.WebHome]] and CAS [[Dimensions>>doc:sdmx:Glossary.Dimension.WebHome]].
1039
1040 __Provision Agreements CENSUS_CUBE2_IT__
1041
1042 1. Restricts the [[codes>>doc:sdmx:Glossary.Code.WebHome]] for the GEO [[Dimension>>doc:sdmx:Glossary.Dimension.WebHome]] to IT and its children.
1043 1. Inherits the (% style="color:#e74c3c" %)constraints(%%) from [[Dataflow>>doc:sdmx:Glossary.Dataflow.WebHome]] CENSUS_CUBE2 for the CAS [[Dimension>>doc:sdmx:Glossary.Dimension.WebHome]].
1044 1. Inherits the [[AGE>>doc:sdmx:Glossary.Age.WebHome]] (% style="color:#e74c3c" %)constraint(%%) applied at the (% style="color:#e74c3c" %)level(%%) of the [[DSD>>doc:sdmx:Glossary.Data structure definition.WebHome]].
1045
1046 The (% style="color:#e74c3c" %)constraints(%%) are defined as follows:
1047
1048 __DSD Constraint__
1049
1050 [[image:1747836776698-720.jpeg]]
1051
1052 __[[Dataflow>>doc:sdmx:Glossary.Dataflow.WebHome]] (% style="color:#e74c3c" %)Constraints(%%)__
1053
1054 [[image:1747836776701-360.jpeg]]
1055
1056 [[image:1747836776707-834.jpeg]]
1057
1058 __Provision Agreement Constraint__
1059
1060 [[image:1747836776710-262.jpeg]]
1061
1062 = 9 Transforming between versions of SDMX =
1063
1064 == 9.1 Scope ==
1065
1066 The scope of this section is to define both best practices and mandatory behaviour for specific aspects of transformation between different formats of [[SDMX>>doc:sdmx:Glossary.Statistical data and metadata exchange.WebHome]].
1067
1068 == 9.2 Groups and Dimension Groups ==
1069
1070 === 9.2.1 Issue ===
1071
1072 (% style="color:#e74c3c" %)Version(%%) 2.1 introduces a more granular mechanism for specifying the relationship between a Data [[Attribute>>doc:sdmx:Glossary.Attribute.WebHome]] and the [[Dimensions>>doc:sdmx:Glossary.Dimension.WebHome]] to which the [[attribute>>doc:sdmx:Glossary.Attribute.WebHome]] applies. The technical construct for this is the [[Dimension>>doc:sdmx:Glossary.Dimension.WebHome]] Group. This [[Dimension>>doc:sdmx:Glossary.Dimension.WebHome]] Group has no direct equivalent in (% style="color:#e74c3c" %)versions(%%) 2.0 and 1.0 and so the application transforming data from a (% style="color:#e74c3c" %)version(%%) 2.1 [[data set>>doc:sdmx:Glossary.Data set.WebHome]] to a (% style="color:#e74c3c" %)version(%%) 2.0 or (% style="color:#e74c3c" %)version(%%) 1.0 [[data set>>doc:sdmx:Glossary.Data set.WebHome]] must decide to which construct the [[attribute>>doc:sdmx:Glossary.Attribute.WebHome]] value, whose [[Attribute>>doc:sdmx:Glossary.Attribute.WebHome]] is declared in a [[Dimension>>doc:sdmx:Glossary.Dimension.WebHome]] Group, should be attached. The closest construct is the “Series” [[attachment level>>doc:sdmx:Glossary.Attachment level.WebHome]] and in many cases this is the correct construct to use.
1073
1074 However, there is one case where the [[attribute>>doc:sdmx:Glossary.Attribute.WebHome]] MUST be attached to a Group in the (% style="color:#e74c3c" %)version(%%) 2.0 and 1.0 message. The conditions of this case are:
1075
1076 1. A Group is defined in the [[DSD>>doc:sdmx:Glossary.Data structure definition.WebHome]] with exactly the same [[Dimensions>>doc:sdmx:Glossary.Dimension.WebHome]] as a [[Dimension>>doc:sdmx:Glossary.Dimension.WebHome]] Group in the same [[DSD>>doc:sdmx:Glossary.Data structure definition.WebHome]].
1077 1. The [[Attribute>>doc:sdmx:Glossary.Attribute.WebHome]] is defined in the [[DSD>>doc:sdmx:Glossary.Data structure definition.WebHome]] with an [[Attribute Relationship>>doc:sdmx:Glossary.Attribute relationship.WebHome]] to the [[Dimension>>doc:sdmx:Glossary.Dimension.WebHome]] Group. This [[attribute>>doc:sdmx:Glossary.Attribute.WebHome]] is NOT defined as having an [[Attribute Relationship>>doc:sdmx:Glossary.Attribute relationship.WebHome]] to the Group.
1078
1079 === 9.2.2 Structural Metadata ===
1080
1081 If the conditions defined in 9.2.1are true then on conversion to a (% style="color:#e74c3c" %)version(%%) 2.0 or 1.0 [[DSD>>doc:sdmx:Glossary.Data structure definition.WebHome]] (Key Family) the [[Component>>doc:sdmx:Glossary.Component.WebHome]]/[[Attribute>>doc:sdmx:Glossary.Attribute.WebHome]].attachmentLevel must be set to “Group” and the [[Component>>doc:sdmx:Glossary.Component.WebHome]]/[[Attribute>>doc:sdmx:Glossary.Attribute.WebHome]]/AttachmentGroup” is used to identify the Group. Note that under rule(1) in 1.2.1 this group will have been defined in the V 2.1 [[DSD>>doc:sdmx:Glossary.Data structure definition.WebHome]] and so will be present in the V 2.0 transformation.
1082
1083 === 9.2.3 Data ===
1084
1085 If the conditions defined in 9.2.1are true then, on conversion from a 2.1 [[data set>>doc:sdmx:Glossary.Data set.WebHome]] to a 2.0 or 1.0 [[dataset>>doc:sdmx:Glossary.Data set.WebHome]] the [[attribute>>doc:sdmx:Glossary.Attribute.WebHome]] value will be placed in the relevant . If these conditions are not true then the [[attribute>>doc:sdmx:Glossary.Attribute.WebHome]] value will be placed in the .
1086
1087 === 9.2.4 Compact Schema ===
1088
1089 If the conditions defined in 9.2.1are true then the Compact Schema must be generated with the Group present and the [[Attribute>>doc:sdmx:Glossary.Attribute.WebHome]](s) present in that group definition.
1090
1091 = 10 Validation and Transformation Language (VTL) =
1092
1093 == 10.1 Introduction ==
1094
1095 The [[Validation and Transformation Language>>doc:sdmx:Glossary.Validation and transformation language.WebHome]] ([[VTL>>doc:sdmx:Glossary.Validation and transformation language.WebHome]]) supports the definition of Transformations, which are algorithms to calculate new data starting from already existing ones{{footnote}}The Validation and Transformation Language is a standard language designed and published under the SDMX initiative. VTL is described in the VTL User and Reference Guides available on the SDMX website https://sdmx.org.{{/footnote}}. The purpose of the [[VTL>>doc:sdmx:Glossary.Validation and transformation language.WebHome]] in the [[SDMX>>doc:sdmx:Glossary.Statistical data and metadata exchange.WebHome]] context is to enable the:
1096
1097 * definition of validation and transformation algorithms, in order to specify how to calculate new data from existing ones;
1098 * exchange of the definition of [[VTL>>doc:sdmx:Glossary.Validation and transformation language.WebHome]] algorithms, also together the definition of the data structures of the involved data (for example, exchange the data structures of a reporting framework together with the validation rules to be applied, exchange the input and output data structures of a calculation task together with the [[VTL>>doc:sdmx:Glossary.Validation and transformation language.WebHome]] Transformations describing the calculation algorithms);
1099 * compilation and execution of [[VTL>>doc:sdmx:Glossary.Validation and transformation language.WebHome]] algorithms, either interpreting the [[VTL>>doc:sdmx:Glossary.Validation and transformation language.WebHome]] transformations or translating them in whatever other computer language is deemed as appropriate.
1100
1101 It is important to note that the [[VTL>>doc:sdmx:Glossary.Validation and transformation language.WebHome]] has its own information model (IM), derived from the Generic Statistical Information Model (GSIM) and described in the [[VTL>>doc:sdmx:Glossary.Validation and transformation language.WebHome]] User Guide. The [[VTL>>doc:sdmx:Glossary.Validation and transformation language.WebHome]] IM is designed to be compatible with more standards, like [[SDMX>>doc:sdmx:Glossary.Statistical data and metadata exchange.WebHome]], DDI (Data Documentation Initiative) and GSIM, and includes the model [[artefacts>>doc:sdmx:Glossary.Artefact.WebHome]] that can be manipulated (inputs and/or outputs of transformations, e.g. “[[Data Set>>doc:sdmx:Glossary.Data set.WebHome]]”, “Data Structure”) and the model [[artefacts>>doc:sdmx:Glossary.Artefact.WebHome]] that allow the definition of the transformation algorithms (e.g. “Transformation”, “Transformation Scheme”).
1102
1103 The [[VTL>>doc:sdmx:Glossary.Validation and transformation language.WebHome]] language can be applied to [[SDMX>>doc:sdmx:Glossary.Statistical data and metadata exchange.WebHome]] [[artefacts>>doc:sdmx:Glossary.Artefact.WebHome]] by (% style="color:#e74c3c" %)mapping(%%) the [[SDMX>>doc:sdmx:Glossary.Statistical data and metadata exchange.WebHome]] IM model [[artefacts>>doc:sdmx:Glossary.Artefact.WebHome]] to the model [[artefacts>>doc:sdmx:Glossary.Artefact.WebHome]] that [[VTL>>doc:sdmx:Glossary.Validation and transformation language.WebHome]] can manipulate. Thus, the [[SDMX>>doc:sdmx:Glossary.Statistical data and metadata exchange.WebHome]] [[artefacts>>doc:sdmx:Glossary.Artefact.WebHome]] can be used in [[VTL>>doc:sdmx:Glossary.Validation and transformation language.WebHome]] as inputs and/or outputs of transformations. It is important to be aware that the [[artefacts>>doc:sdmx:Glossary.Artefact.WebHome]] do not always have the same names in the [[SDMX>>doc:sdmx:Glossary.Statistical data and metadata exchange.WebHome]] and [[VTL>>doc:sdmx:Glossary.Validation and transformation language.WebHome]] IMs, nor do they always have the same meaning. The more evident example is given by the [[SDMX>>doc:sdmx:Glossary.Statistical data and metadata exchange.WebHome]] [[Dataset>>doc:sdmx:Glossary.Data set.WebHome]] and the [[VTL>>doc:sdmx:Glossary.Validation and transformation language.WebHome]] “[[Data Set>>doc:sdmx:Glossary.Data set.WebHome]]”, which do not correspond one another: as a matter of fact, the [[VTL>>doc:sdmx:Glossary.Validation and transformation language.WebHome]] “[[Data Set>>doc:sdmx:Glossary.Data set.WebHome]]” (% style="color:#e74c3c" %)maps(%%) to the [[SDMX>>doc:sdmx:Glossary.Statistical data and metadata exchange.WebHome]] “[[Dataflow>>doc:sdmx:Glossary.Dataflow.WebHome]]”, while the [[SDMX>>doc:sdmx:Glossary.Statistical data and metadata exchange.WebHome]] “[[Dataset>>doc:sdmx:Glossary.Data set.WebHome]]” has no explicit (% style="color:#e74c3c" %)mapping(%%) to [[VTL>>doc:sdmx:Glossary.Validation and transformation language.WebHome]] (such an abstraction is not needed in the definition of [[VTL>>doc:sdmx:Glossary.Validation and transformation language.WebHome]] transformations). A [[SDMX>>doc:sdmx:Glossary.Statistical data and metadata exchange.WebHome]] “[[Dataset>>doc:sdmx:Glossary.Data set.WebHome]]”, however, is an instance of a [[SDMX>>doc:sdmx:Glossary.Statistical data and metadata exchange.WebHome]] “[[Dataflow>>doc:sdmx:Glossary.Dataflow.WebHome]]” and can be the [[artefact>>doc:sdmx:Glossary.Artefact.WebHome]] on which the [[VTL>>doc:sdmx:Glossary.Validation and transformation language.WebHome]] transformations are executed (i.e., the transformations are defined on [[Dataflows>>doc:sdmx:Glossary.Dataflow.WebHome]] and are applied to [[Dataflow>>doc:sdmx:Glossary.Dataflow.WebHome]] instances that can be Datasets).
1104
1105 The [[VTL>>doc:sdmx:Glossary.Validation and transformation language.WebHome]] programs (Transformation Schemes) are represented in [[SDMX>>doc:sdmx:Glossary.Statistical data and metadata exchange.WebHome]] through the TransformationScheme maintainable class which is composed of Transformation ([[nameable artefact>>doc:sdmx:Glossary.Nameable artefact.WebHome]]). Each Transformation assigns the outcome of the evaluation of a [[VTL>>doc:sdmx:Glossary.Validation and transformation language.WebHome]] expression to a result.
1106
1107 This section does not explain the [[VTL>>doc:sdmx:Glossary.Validation and transformation language.WebHome]] language or any of the content published in the [[VTL>>doc:sdmx:Glossary.Validation and transformation language.WebHome]] guides. Rather, this is a description of how the [[VTL>>doc:sdmx:Glossary.Validation and transformation language.WebHome]] can be used in the [[SDMX>>doc:sdmx:Glossary.Statistical data and metadata exchange.WebHome]] context and applied to [[SDMX>>doc:sdmx:Glossary.Statistical data and metadata exchange.WebHome]] [[artefacts>>doc:sdmx:Glossary.Artefact.WebHome]].
1108
1109 == 10.2 References to SDMX artefacts from VTL statements ==
1110
1111 === 10.2.1 Introduction ===
1112
1113 The [[VTL>>doc:sdmx:Glossary.Validation and transformation language.WebHome]] can manipulate [[SDMX>>doc:sdmx:Glossary.Statistical data and metadata exchange.WebHome]] [[artefacts>>doc:sdmx:Glossary.Artefact.WebHome]] (or objects) by referencing them through pre-defined conventional names (aliases).
1114
1115 The alias of a [[SDMX>>doc:sdmx:Glossary.Statistical data and metadata exchange.WebHome]] [[artefact>>doc:sdmx:Glossary.Artefact.WebHome]] can be its URN (Universal Resource Name), an abbreviation of its URN or another user-defined name.
1116
1117 In any case, the aliases used in the [[VTL>>doc:sdmx:Glossary.Validation and transformation language.WebHome]] transformations have to be (% style="color:#e74c3c" %)mapped(%%) to the [[SDMX>>doc:sdmx:Glossary.Statistical data and metadata exchange.WebHome]] [[artefacts>>doc:sdmx:Glossary.Artefact.WebHome]] through the VtlMappingScheme and VtlMapping classes (see the section of the [[SDMX>>doc:sdmx:Glossary.Statistical data and metadata exchange.WebHome]] IM relevant to the [[VTL>>doc:sdmx:Glossary.Validation and transformation language.WebHome]]). A VtlMapping allows specifying the aliases to be used in the [[VTL>>doc:sdmx:Glossary.Validation and transformation language.WebHome]] transformations, rulesets{{footnote}}See also the section “VTL-DL Rulesets” in the VTL Reference Manual.{{/footnote}} or user defined operators{{footnote}}The VTLMapping are used also for User Defined Operators (UDO). Although UDOperators are envisaged to be defined on generic operands, so that the specific artefacts to be manipulated are passed as parameters at their invocation, it is also possible that an UDOperator invokes directly some specific SDMX artefacts. These SDMX artefacts have to be mapped to the corresponding aliases used in the definition of the UDO through the VtlMappingScheme and VtlMapping classes as well. {{/footnote}} to reference [[SDMX>>doc:sdmx:Glossary.Statistical data and metadata exchange.WebHome]] [[artefacts>>doc:sdmx:Glossary.Artefact.WebHome]]. A VtlMappingScheme is a container for zero or more VtlMapping.
1118
1119 The correspondence between an alias and a [[SDMX>>doc:sdmx:Glossary.Statistical data and metadata exchange.WebHome]] [[artefact>>doc:sdmx:Glossary.Artefact.WebHome]] must be one-to-one, meaning that a generic alias identifies one and just one [[SDMX>>doc:sdmx:Glossary.Statistical data and metadata exchange.WebHome]] [[artefact>>doc:sdmx:Glossary.Artefact.WebHome]] while a [[SDMX>>doc:sdmx:Glossary.Statistical data and metadata exchange.WebHome]] [[artefact>>doc:sdmx:Glossary.Artefact.WebHome]] is identified by one and just one alias. In other words, within a VtlMappingScheme an [[artefact>>doc:sdmx:Glossary.Artefact.WebHome]] can have just one alias and different [[artefacts>>doc:sdmx:Glossary.Artefact.WebHome]] cannot have the same alias.
1120
1121 The references through the URN and the abbreviated URN are described in the following paragraphs.
1122
1123 === 10.2.2 References through the URN ===
1124
1125 This approach has the advantage that in the [[VTL>>doc:sdmx:Glossary.Validation and transformation language.WebHome]] [[code>>doc:sdmx:Glossary.Code.WebHome]] the URN of the referenced [[artefacts>>doc:sdmx:Glossary.Artefact.WebHome]] is directly intelligible by a human reader but has the drawback that the references are verbose.
1126
1127 The [[SDMX>>doc:sdmx:Glossary.Statistical data and metadata exchange.WebHome]] URN{{footnote}}For a complete description of the structure of the URN see the SDMX 2.1 Standards - Section 5 - Registry Specifications, paragraph 6.2.2 (“Universal Resource Name (URN)”).{{/footnote}} is the concatenation of the following parts, separated by special symbols like dot, equal, asterisk, comma, and parenthesis:^^ ^^
1128
1129 * SDMXprefix
1130 * SDMX-IM-package-name
1131 * class-name
1132 * agency-id
1133 * maintainedobject-id
1134 * maintainedobject-version
1135 * container-object-id{{footnote}}The container-object-id can repeat and may not be present.{{/footnote}}
1136 * object-id
1137
1138 The generic structure of the URN is the following:
1139
1140 SDMXprefix**.**SDMX-IM-package-name**.**class-name**=**agency-id**:**maintainedobject-id **(**maintainedobject-version**).***container-object-id**.**object-id
1141
1142 The **[[SDMX>>doc:sdmx:Glossary.Statistical data and metadata exchange.WebHome]] prefix** is “urn:sdmx:org”, always the same for all [[SDMX>>doc:sdmx:Glossary.Statistical data and metadata exchange.WebHome]] [[artefacts>>doc:sdmx:Glossary.Artefact.WebHome]].
1143
1144 The **[[SDMX-IM>>doc:sdmx:Glossary.SDMX Information Model.WebHome]]-package-name **is the concatenation of the string** **“[[sdmx>>doc:sdmx:Glossary.Statistical data and metadata exchange.WebHome]].infomodel.” with the package-name which the [[artefact>>doc:sdmx:Glossary.Artefact.WebHome]] belongs to. For example, for referencing a [[dataflow>>doc:sdmx:Glossary.Dataflow.WebHome]] the SDMX-IM-package-name is “sdmx.infomodel.datastructure”, because the class [[Dataflow>>doc:sdmx:Glossary.Dataflow.WebHome]] belongs to the package “datastructure”.
1145
1146 The **class-name** is the name of the [[SDMX>>doc:sdmx:Glossary.Statistical data and metadata exchange.WebHome]] object class which the [[SDMX>>doc:sdmx:Glossary.Statistical data and metadata exchange.WebHome]] object belongs to (e.g., for referencing a [[dataflow>>doc:sdmx:Glossary.Dataflow.WebHome]] the class-name is “[[Dataflow>>doc:sdmx:Glossary.Dataflow.WebHome]]”). The [[VTL>>doc:sdmx:Glossary.Validation and transformation language.WebHome]] can reference [[SDMX>>doc:sdmx:Glossary.Statistical data and metadata exchange.WebHome]] [[artefacts>>doc:sdmx:Glossary.Artefact.WebHome]] that belong to the classes [[Dataflow>>doc:sdmx:Glossary.Dataflow.WebHome]], [[Dimension>>doc:sdmx:Glossary.Dimension.WebHome]], MeasureDimension, TimeDimension, PrimaryMeasure, DataAttribute, (% style="color:#e74c3c" %)Concept(%%), ConceptScheme, Codelist.
1147
1148 The **agency-id** is the acronym of the agency that owns the definition of the [[artefact>>doc:sdmx:Glossary.Artefact.WebHome]], for example for the Eurostat [[artefacts>>doc:sdmx:Glossary.Artefact.WebHome]] the agency-id is “ESTAT”). The agency-id can be composite (for example AgencyA.Dept1.Unit2).
1149
1150 The **maintainedobject-id** is the name of the maintained object which the [[artefact>>doc:sdmx:Glossary.Artefact.WebHome]] belongs to, and in case the [[artefact>>doc:sdmx:Glossary.Artefact.WebHome]] itself is maintainable{{footnote}}i.e., the artefact belongs to a maintainable class{{/footnote}}, coincides with the name of the [[artefact>>doc:sdmx:Glossary.Artefact.WebHome]]. Therefore the maintainedobject-id depends on the class of the [[artefact>>doc:sdmx:Glossary.Artefact.WebHome]]:
1151
1152 * if the [[artefact>>doc:sdmx:Glossary.Artefact.WebHome]] is a [[Dataflow>>doc:sdmx:Glossary.Dataflow.WebHome]], which is a maintainable class, the maintainedobject-id is the [[Dataflow>>doc:sdmx:Glossary.Dataflow.WebHome]] name ([[dataflow>>doc:sdmx:Glossary.Dataflow.WebHome]]-id);
1153 * if the [[artefact>>doc:sdmx:Glossary.Artefact.WebHome]] is a [[Dimension>>doc:sdmx:Glossary.Dimension.WebHome]], MeasureDimension, TimeDimension, PrimaryMeasure or DataAttribute, which are not maintainable and belong to the DataStructure maintainable class, the maintainedobject-id is the name of the DataStructure (dataStructure-id) which the [[artefact>>doc:sdmx:Glossary.Artefact.WebHome]] belongs to;
1154 * if the [[artefact>>doc:sdmx:Glossary.Artefact.WebHome]] is a (% style="color:#e74c3c" %)Concept(%%), which is not maintainable and belongs to the ConceptScheme maintainable class, ,, ,,the maintainedobject-id is the name of the ConceptScheme (conceptScheme-id) which the [[artefact>>doc:sdmx:Glossary.Artefact.WebHome]] belongs to;
1155 * if the [[artefact>>doc:sdmx:Glossary.Artefact.WebHome]] is a ConceptScheme, which is a maintainable class, ,, ,,the maintainedobject-id is the name of the ConceptScheme (conceptScheme-id);
1156 * if the [[artefact>>doc:sdmx:Glossary.Artefact.WebHome]] is a Codelist, which is a maintainable class, the maintainedobject-id is the Codelist name (codelist-id).
1157
1158 The **maintainedobject-(% style="color:#e74c3c" %)version(%%)** is the (% style="color:#e74c3c" %)version(%%) of the maintained object which the [[artefact>>doc:sdmx:Glossary.Artefact.WebHome]] belongs to (for example, possible (% style="color:#e74c3c" %)versions(%%) are 1.0, 2.1, 3.1.2).
1159
1160 The **container-object-id** does not apply to the classes that can be referenced in [[VTL>>doc:sdmx:Glossary.Validation and transformation language.WebHome]] transformations, therefore is not present in their URN
1161
1162 The **object-id** is the name of the non-[[maintainable artefact>>doc:sdmx:Glossary.Maintainable artefact.WebHome]] (when the [[artefact>>doc:sdmx:Glossary.Artefact.WebHome]] is maintainable its name is already specified as the maintainedobject-id, see above), in particular it has to be specified:
1163
1164 * if the [[artefact>>doc:sdmx:Glossary.Artefact.WebHome]] is a [[Dimension>>doc:sdmx:Glossary.Dimension.WebHome]], MeasureDimension, TimeDimension, PrimaryMeasure or DataAttribute (the object-id is the name of one of the [[artefacts>>doc:sdmx:Glossary.Artefact.WebHome]] above, which are data structure [[components>>doc:sdmx:Glossary.Component.WebHome]])
1165 * if the [[artefact>>doc:sdmx:Glossary.Artefact.WebHome]] is a (% style="color:#e74c3c" %)Concept(%%) (the object-id is the name of the (% style="color:#e74c3c" %)Concept(%%))
1166
1167 For example, by using the URN, the [[VTL>>doc:sdmx:Glossary.Validation and transformation language.WebHome]] transformation that sums two [[SDMX>>doc:sdmx:Glossary.Statistical data and metadata exchange.WebHome]] [[dataflows>>doc:sdmx:Glossary.Dataflow.WebHome]] DF1 and DF2 and assigns the result to a third persistent [[dataflow>>doc:sdmx:Glossary.Dataflow.WebHome]] DFR, assuming that DF1, DF2 and DFR are the maintainedobject-id of the three [[dataflows>>doc:sdmx:Glossary.Dataflow.WebHome]], that their (% style="color:#e74c3c" %)version(%%) is 1.0 and their Agency is AG, would be written as{{footnote}}Since these references to SDMX objects include non-permitted characters as per the VTL ID notation, they need to be included between single quotes, according to the VTL rules for irregular names.{{/footnote}}:
1168
1169 ‘urn:sdmx:org.sdmx.infomodel.datastructure.Dataflow=AG:DFR(1.0)’  <-
1170 ‘urn:sdmx:org.sdmx.infomodel.datastructure.Dataflow=AG:DF1(1.0)’  +
1171 ‘urn:sdmx:org.sdmx.infomodel.datastructure.Dataflow=AG:DF2(1.0)’
1172
1173 === 10.2.3 Abbreviation of the URN ===
1174
1175 The complete formulation of the URN described above is exhaustive but verbose, even for very simple statements. In order to reduce the verbosity through a simplified identifier and make the work of transformation definers easier, proper abbreviations of the URN are possible. Using this approach, the referenced [[artefacts>>doc:sdmx:Glossary.Artefact.WebHome]] remain intelligible in the [[VTL>>doc:sdmx:Glossary.Validation and transformation language.WebHome]] code by a human reader.
1176
1177 The URN can be abbreviated by omitting the parts that are not essential for the identification of the [[artefact>>doc:sdmx:Glossary.Artefact.WebHome]] or that can be deduced from other available information, including the context in which the invocation is made. The possible abbreviations are described below.
1178
1179 * The **SDMXPrefix** can be omitted for all the [[SDMX>>doc:sdmx:Glossary.Statistical data and metadata exchange.WebHome]] objects, because it is a prefixed string (urn:[[sdmx>>doc:sdmx:Glossary.Statistical data and metadata exchange.WebHome]]:org), always the same for [[SDMX>>doc:sdmx:Glossary.Statistical data and metadata exchange.WebHome]] objects.
1180 * The **[[SDMX-IM>>doc:sdmx:Glossary.SDMX Information Model.WebHome]]-package-name **can be omitted as well because it can be deduced from the class-name that follows it (the table of the [[SDMX-IM>>doc:sdmx:Glossary.SDMX Information Model.WebHome]] packages and classes that allows this deduction is in the [[SDMX>>doc:sdmx:Glossary.Statistical data and metadata exchange.WebHome]] 2.1 Standards - Section 5 - Registry Specifications, paragraph 6.2.3). In particular, considering the object classes of the [[artefacts>>doc:sdmx:Glossary.Artefact.WebHome]] that [[VTL>>doc:sdmx:Glossary.Validation and transformation language.WebHome]] can reference, the package is: 
1181 ** “datastructure” for the classes [[Dataflow>>doc:sdmx:Glossary.Dataflow.WebHome]], [[Dimension>>doc:sdmx:Glossary.Dimension.WebHome]], MeasureDimension, TimeDimension, PrimaryMeasure, DataAttribute,
1182 ** “conceptscheme” for the classes (% style="color:#e74c3c" %)Concept(%%) and ConceptScheme
1183 ** “codelist” for the class Codelist.
1184 * The **class-name** can be omitted as it can be deduced from the [[VTL>>doc:sdmx:Glossary.Validation and transformation language.WebHome]] invocation. In particular, starting from the [[VTL>>doc:sdmx:Glossary.Validation and transformation language.WebHome]] class of the invoked [[artefact>>doc:sdmx:Glossary.Artefact.WebHome]] (e.g. [[dataset>>doc:sdmx:Glossary.Data set.WebHome]], [[component>>doc:sdmx:Glossary.Component.WebHome]], identifier, [[measure>>doc:sdmx:Glossary.Measure.WebHome]], [[attribute>>doc:sdmx:Glossary.Attribute.WebHome]], variable, valuedomain), which is known given the syntax of the invoking [[VTL>>doc:sdmx:Glossary.Validation and transformation language.WebHome]] operator{{footnote}}For the syntax of the VTL operators see the VTL Reference Manual{{/footnote}}, the [[SDMX>>doc:sdmx:Glossary.Statistical data and metadata exchange.WebHome]] class can be deduced from the mapping rules between [[VTL>>doc:sdmx:Glossary.Validation and transformation language.WebHome]] and [[SDMX>>doc:sdmx:Glossary.Statistical data and metadata exchange.WebHome]] (see the section “Mapping between [[VTL>>doc:sdmx:Glossary.Validation and transformation language.WebHome]] and [[SDMX>>doc:sdmx:Glossary.Statistical data and metadata exchange.WebHome]]” hereinafter){{footnote}}In case the invoked artefact is a VTL component, which can be invoked only within the invocation of a VTL data set (SDMX dataflow), the specific SDMX class-name (e.g. Dimension, MeasureDimension, TimeDimension, PrimaryMeasure or DataAttribute) can be deduced from the data structure of the SDMX Dataflow which the component belongs to.{{/footnote}}.
1185 * If the **agency-id** is not specified, it is assumed by default equal to the agency-id of the TransformationScheme, UserDefinedOperatorScheme or RulesetScheme from which the [[artefact>>doc:sdmx:Glossary.Artefact.WebHome]] is invoked. For example, the agency-id can be omitted if it is the same as the invoking TransformationScheme and cannot be omitted if the [[artefact>>doc:sdmx:Glossary.Artefact.WebHome]] comes from another agency.{{footnote}}If the Agency is composite (for example AgencyA.Dept1.Unit2), the agency is considered different even if only part of the composite name is different (for example AgencyA.Dept1.Unit3 is a different Agency than the previous one). Moreover the agency-id cannot be omitted in part (i.e., if a TransformationScheme owned by AgencyA.Dept1.Unit2 references an artefact coming from AgencyA.Dept1.Unit3, the specification of the agency-id becomes mandatory and must be complete, without omitting the possibly equal parts like AgencyA.Dept1){{/footnote}}(% style="font-size:12px" %) (%%)Take also into account that, according to the [[VTL>>doc:sdmx:Glossary.Validation and transformation language.WebHome]] consistency rules, the agency of the result of a Transformation must be the same as its TransformationScheme, therefore the agency-id can be omitted for all the results (left part of Transformation statements).
1186 * As for the **maintainedobject-id**, this is essential in some cases while in other cases it can be omitted: o if the referenced [[artefact>>doc:sdmx:Glossary.Artefact.WebHome]] is a [[Dataflow>>doc:sdmx:Glossary.Dataflow.WebHome]], which is a maintainable class, the maintainedobject-id is the [[dataflow>>doc:sdmx:Glossary.Dataflow.WebHome]]-id and obviously cannot be omitted;
1187 ** if the referenced [[artefact>>doc:sdmx:Glossary.Artefact.WebHome]] is a [[Dimension>>doc:sdmx:Glossary.Dimension.WebHome]], MeasureDimension, TimeDimension, PrimaryMeasure, DataAttribute, which are not maintainable and belong to the DataStructure maintainable class, the maintainedobject-id is the dataStructure-id and can be omitted, given that these [[components>>doc:sdmx:Glossary.Component.WebHome]] are always invoked within the invocation of a [[Dataflow>>doc:sdmx:Glossary.Dataflow.WebHome]], whose dataStructure-id can be deduced from the [[SDMX>>doc:sdmx:Glossary.Statistical data and metadata exchange.WebHome]] structural definitions;
1188 ** if the referenced [[artefact>>doc:sdmx:Glossary.Artefact.WebHome]] is a (% style="color:#e74c3c" %)Concept(%%), which is not maintainable and belong to the ConceptScheme maintainable class,,, ,,the maintained object is the conceptScheme-id and cannot be omitted;
1189 ** if the referenced [[artefact>>doc:sdmx:Glossary.Artefact.WebHome]] is a ConceptScheme, which is a,, ,,maintainable class,,, ,,the maintained object is the conceptScheme-id and obviously cannot be omitted;
1190 ** if the referenced [[artefact>>doc:sdmx:Glossary.Artefact.WebHome]] is a Codelist, which is a maintainable class, the maintainedobject-id is the codelist-id and obviously cannot be omitted.
1191 * When the maintainedobject-id is omitted, the **maintainedobject-(% style="color:#e74c3c" %)version(%%)** is omitted too. When the maintainedobject-id is not omitted and the maintainedobject-(% style="color:#e74c3c" %)version(%%) is omitted, the (% style="color:#e74c3c" %)version(%%) 1.0 is assumed by default.,, ,,
1192 * As said, the **container-object-id** does not apply to the classes that can be referenced in [[VTL>>doc:sdmx:Glossary.Validation and transformation language.WebHome]] transformations, therefore is not present in their URN
1193 * The **object-id** does not exist for the [[artefacts>>doc:sdmx:Glossary.Artefact.WebHome]] belonging to the [[Dataflow>>doc:sdmx:Glossary.Dataflow.WebHome]], ConceptScheme and Codelist classes, while it exists and cannot be omitted for the [[artefacts>>doc:sdmx:Glossary.Artefact.WebHome]] belonging to the classes [[Dimension>>doc:sdmx:Glossary.Dimension.WebHome]], MeasureDimension, TimeDimension, PrimaryMeasure, DataAttribute and (% style="color:#e74c3c" %)Concept(%%), as for them the object-id is the main identifier of the [[artefact>>doc:sdmx:Glossary.Artefact.WebHome]]
1194
1195 The simplified object identifier is obtained by omitting all the first part of the URN, including the special characters, till the first part not omitted.
1196
1197 For example, the full formulation that uses the complete URN shown at the end of the previous paragraph:
1198
1199 ‘urn:sdmx:org.sdmx.infomodel.datastructure.Dataflow=AG:DFR(1.0)’  :=
1200 ‘urn:sdmx:org.sdmx.infomodel.datastructure.Dataflow=AG:DF1(1.0)’   +
1201 ‘urn:sdmx:org.sdmx.infomodel.datastructure.Dataflow=AG:DF2(1.0)’
1202
1203 by omitting all the non-essential parts would become simply:
1204
1205 DFR := DF1 + DF2
1206
1207 The references to the Codelists can be simplified similarly. For example, given the non-abbreviated reference to the Codelist AG:CL_FREQ(1.0), which is{{footnote}}Single quotes are needed because this reference is not a VTL regular name.{{/footnote}}:
1208
1209 ‘urn:sdmx:org.sdmx.infomodel.codelist.Codelist=AG:CL_FREQ(1.0)’
1210
1211 if the Codelist is referenced from a ruleset scheme belonging to the agency AG, omitting all the optional parts, the abbreviated reference would become simply{{footnote}}Single quotes are not needed in this case because CL_FREQ is a VTL regular name.{{/footnote}}:
1212
1213 CL_FREQ
1214
1215 As for the references to the components, it can be enough to specify the componentId, given that the dataStructure-Id can be omitted. An example of non-abbreviated reference, if the data structure is DST1 and the component is SECTOR, is the following:
1216
1217 ‘urn:sdmx:org.sdmx.infomodel.datastructure.DataStructure=AG:DST1(1.0).SECTOR’
1218
1219 The corresponding fully abbreviated reference, if made from a transformation scheme belonging to AG, would become simply:
1220
1221 SECTOR
1222
1223 For example, the transformation for renaming the [[component>>doc:sdmx:Glossary.Component.WebHome]] SECTOR of the [[dataflow>>doc:sdmx:Glossary.Dataflow.WebHome]] DF1 into SEC can be written as{{footnote}}The result DFR(1.0) is be equal to DF1(1.0) save that the component SECTOR is called SEC{{/footnote}}:
1224
1225 ‘DFR(1.0)’ := ‘DF1(1.0)’ [rename SECTOR to SEC]
1226
1227 In the references to the (% style="color:#e74c3c" %)Concepts(%%), which can exist for example in the definition of the [[VTL>>doc:sdmx:Glossary.Validation and transformation language.WebHome]] Rulesets, at least the conceptScheme-id and the (% style="color:#e74c3c" %)concept(%%)-id must be specified.
1228
1229 An example of non-abbreviated reference, if the conceptScheme-id is CS1 and the (% style="color:#e74c3c" %)concept(%%)-id is SECTOR, is the following:
1230
1231 ‘urn:sdmx:org.sdmx.infomodel.conceptscheme.(% style="color:#e74c3c" %)Concept(%%)=AG:CS1(1.0).SECTOR’
1232
1233 The corresponding fully abbreviated reference, if made from a RulesetScheme belonging to AG, would become simply:
1234
1235 CS1(1.0).SECTOR
1236
1237 The [[Codes>>doc:sdmx:Glossary.Code.WebHome]] and in general all the Values can be written without any other specification, for example, the transformation to check if the values of the [[measures>>doc:sdmx:Glossary.Measure.WebHome]] of the [[dataflow>>doc:sdmx:Glossary.Dataflow.WebHome]] DF1 are between 0 and 25000 can be written like follows:
1238
1239 ‘DFR(1.0)’ := between ( ‘DF1(1.0)’, 0, 25000 )
1240
1241 The [[artefact>>doc:sdmx:Glossary.Artefact.WebHome]] ([[component>>doc:sdmx:Glossary.Component.WebHome]], (% style="color:#e74c3c" %)concept(%%), codelist …) which the Values are referred to can be deduced from the context in which the reference is made, taking also into account the [[VTL>>doc:sdmx:Glossary.Validation and transformation language.WebHome]] syntax. In the transformation above, for example, the values 0 and 2500 are compared to the values of the [[measures>>doc:sdmx:Glossary.Measure.WebHome]] of DF1(1.0).
1242
1243 === 10.2.4 User-defined alias ===
1244
1245 The third possibility for referencing [[SDMX>>doc:sdmx:Glossary.Statistical data and metadata exchange.WebHome]] [[artefacts>>doc:sdmx:Glossary.Artefact.WebHome]] from [[VTL>>doc:sdmx:Glossary.Validation and transformation language.WebHome]] statements is to use user-defined aliases not related to the [[SDMX>>doc:sdmx:Glossary.Statistical data and metadata exchange.WebHome]] URN of the [[artefact>>doc:sdmx:Glossary.Artefact.WebHome]].
1246
1247 This approach gives preference to the use of symbolic names for the [[SDMX>>doc:sdmx:Glossary.Statistical data and metadata exchange.WebHome]] [[artefacts>>doc:sdmx:Glossary.Artefact.WebHome]]. As a consequence, in the [[VTL>>doc:sdmx:Glossary.Validation and transformation language.WebHome]] code the referenced [[artefacts>>doc:sdmx:Glossary.Artefact.WebHome]] would become not directly intelligible by a human reader. In any case, the [[VTL>>doc:sdmx:Glossary.Validation and transformation language.WebHome]] aliases are associated to the [[SDMX>>doc:sdmx:Glossary.Statistical data and metadata exchange.WebHome]] URN through the VtlMappingScheme and VtlMapping classes. These classes provide for structured references to [[SDMX>>doc:sdmx:Glossary.Statistical data and metadata exchange.WebHome]] [[artefacts>>doc:sdmx:Glossary.Artefact.WebHome]] whatever kind of reference is used in [[VTL>>doc:sdmx:Glossary.Validation and transformation language.WebHome]] statements (URN, abbreviated URN or user-defined aliases).
1248
1249 === 10.2.5 References to SDMX artefacts from VTL Rulesets ===
1250
1251 The [[VTL>>doc:sdmx:Glossary.Validation and transformation language.WebHome]] Rulesets allow defining sets of reusable rules that can be applied by some
1252
1253 [[VTL>>doc:sdmx:Glossary.Validation and transformation language.WebHome]] operators, like the ones for validation and hierarchical roll-up. A “rule” consists in a relationship between Values belonging to some Value Domains or taken by some Variables, for example: when the Country is USA then the [[Currency>>doc:sdmx:Glossary.Currency.WebHome]] is USD; (ii) the Benelux is composed by Belgium, Luxembourg, Netherlands.
1254
1255 The [[VTL>>doc:sdmx:Glossary.Validation and transformation language.WebHome]] Rulesets have a signature, in which the Value Domains or the Variables on which the Ruleset is defined are declared, and a body, which contains the rules.
1256
1257 In the signature, given the mapping between [[VTL>>doc:sdmx:Glossary.Validation and transformation language.WebHome]] and [[SDMX>>doc:sdmx:Glossary.Statistical data and metadata exchange.WebHome]] better described in the following paragraphs, a reference to a [[VTL>>doc:sdmx:Glossary.Validation and transformation language.WebHome]] Value Domain becomes a reference to a [[SDMX>>doc:sdmx:Glossary.Statistical data and metadata exchange.WebHome]] Codelist or to a [[SDMX>>doc:sdmx:Glossary.Statistical data and metadata exchange.WebHome]] ConceptScheme (for [[SDMX>>doc:sdmx:Glossary.Statistical data and metadata exchange.WebHome]] [[measure>>doc:sdmx:Glossary.Measure.WebHome]] [[dimensions>>doc:sdmx:Glossary.Dimension.WebHome]]), while a reference to a [[VTL>>doc:sdmx:Glossary.Validation and transformation language.WebHome]] Represented Variable becomes a reference to a [[SDMX>>doc:sdmx:Glossary.Statistical data and metadata exchange.WebHome]] (% style="color:#e74c3c" %)Concept(%%), assuming for it a definite representation{{footnote}}Rulesets of this kind cannot be reused when the referenced Concept has a different representation.{{/footnote}}.
1258
1259 In general, for referencing [[SDMX>>doc:sdmx:Glossary.Statistical data and metadata exchange.WebHome]] Codelists and (% style="color:#e74c3c" %)Concepts(%%), the conventions described in the previous paragraphs apply. In the Ruleset syntax, the elements that reference [[SDMX>>doc:sdmx:Glossary.Statistical data and metadata exchange.WebHome]] [[artefacts>>doc:sdmx:Glossary.Artefact.WebHome]] are called “valueDomain” and “variable” for the Datapoint Rulesets and “ruleValueDomain”, “ruleVariable”, “condValueDomain” “condVariable” for the Hierarchical Rulesets). The syntax of the Ruleset signature allows also to define aliases of the elements above, these aliases are valid only within the specific ruleset definition statement and cannot be (% style="color:#e74c3c" %)mapped(%%) to [[SDMX>>doc:sdmx:Glossary.Statistical data and metadata exchange.WebHome]].{{footnote}}See also the section “VTL-DL Rulesets” in the VTL Reference Manual.{{/footnote}}
1260
1261 In the body of the Rulesets, the [[Codes>>doc:sdmx:Glossary.Code.WebHome]] and in general all the Values can be written without any other specification, because the [[artefact>>doc:sdmx:Glossary.Artefact.WebHome]] which the Values are referred (Codelist, ConceptScheme, (% style="color:#e74c3c" %)Concept(%%)) to can be deduced from the Ruleset signature.
1262
1263 == 10.3 Mapping between SDMX and VTL artefacts ==
1264
1265 === 10.3.1 When the mapping occurs ===
1266
1267 The mapping methods between the [[VTL>>doc:sdmx:Glossary.Validation and transformation language.WebHome]] and [[SDMX>>doc:sdmx:Glossary.Statistical data and metadata exchange.WebHome]] object classes allow transforming a [[SDMX>>doc:sdmx:Glossary.Statistical data and metadata exchange.WebHome]] definition in a [[VTL>>doc:sdmx:Glossary.Validation and transformation language.WebHome]] one and vice-versa for the [[artefacts>>doc:sdmx:Glossary.Artefact.WebHome]] to be manipulated.
1268
1269 It should be remembered that [[VTL>>doc:sdmx:Glossary.Validation and transformation language.WebHome]] programs (i.e. Transformation Schemes) are represented in [[SDMX>>doc:sdmx:Glossary.Statistical data and metadata exchange.WebHome]] through the TransformationScheme maintainable class which is composed of Transformations (nameable [[artefacts>>doc:sdmx:Glossary.Artefact.WebHome]]). Each Transformation assigns the outcome of the evaluation of a [[VTL>>doc:sdmx:Glossary.Validation and transformation language.WebHome]] expression to a result: the input operands of the expression and the result can be [[SDMX>>doc:sdmx:Glossary.Statistical data and metadata exchange.WebHome]] [[artefacts>>doc:sdmx:Glossary.Artefact.WebHome]].
1270
1271 Every time a [[SDMX>>doc:sdmx:Glossary.Statistical data and metadata exchange.WebHome]] object is referenced in a [[VTL>>doc:sdmx:Glossary.Validation and transformation language.WebHome]] Transformation as an input operand, there is the need to generate a [[VTL>>doc:sdmx:Glossary.Validation and transformation language.WebHome]] definition of the object, so that the [[VTL>>doc:sdmx:Glossary.Validation and transformation language.WebHome]] operations can take place. This can be made starting from the [[SDMX>>doc:sdmx:Glossary.Statistical data and metadata exchange.WebHome]] definition and applying a [[SDMX>>doc:sdmx:Glossary.Statistical data and metadata exchange.WebHome]]-[[VTL>>doc:sdmx:Glossary.Validation and transformation language.WebHome]] mapping method in the direction from [[SDMX>>doc:sdmx:Glossary.Statistical data and metadata exchange.WebHome]] to [[VTL>>doc:sdmx:Glossary.Validation and transformation language.WebHome]]. The possible mapping methods from [[SDMX>>doc:sdmx:Glossary.Statistical data and metadata exchange.WebHome]] to [[VTL>>doc:sdmx:Glossary.Validation and transformation language.WebHome]] are described in the following paragraphs and are conceived to allow the automatic deduction of the [[VTL>>doc:sdmx:Glossary.Validation and transformation language.WebHome]] definition of the object from the knowledge of the [[SDMX>>doc:sdmx:Glossary.Statistical data and metadata exchange.WebHome]] definition.
1272
1273 In the opposite direction, every time an object calculated by means of [[VTL>>doc:sdmx:Glossary.Validation and transformation language.WebHome]] must be treated as a [[SDMX>>doc:sdmx:Glossary.Statistical data and metadata exchange.WebHome]] object (for example for exchanging it through [[SDMX>>doc:sdmx:Glossary.Statistical data and metadata exchange.WebHome]]), there is the need of a [[SDMX>>doc:sdmx:Glossary.Statistical data and metadata exchange.WebHome]] definition of the object, so that the [[SDMX>>doc:sdmx:Glossary.Statistical data and metadata exchange.WebHome]] operations can take place. The [[SDMX>>doc:sdmx:Glossary.Statistical data and metadata exchange.WebHome]] definition is needed for the [[VTL>>doc:sdmx:Glossary.Validation and transformation language.WebHome]] objects for which a [[SDMX>>doc:sdmx:Glossary.Statistical data and metadata exchange.WebHome]] use is envisaged{{footnote}}If a calculated artefact is persistent, it needs a persistent definition, i.e. a SDMX definition in a SDMX environment. Also possible calculated artefact that are not persistent may require a SDMX definition, for example when the result of a non-persistent calculation is disseminated through SDMX tools (like an inquiry tool).{{/footnote}}.
1274
1275 The mapping methods from [[VTL>>doc:sdmx:Glossary.Validation and transformation language.WebHome]] to [[SDMX>>doc:sdmx:Glossary.Statistical data and metadata exchange.WebHome]] are described in the following paragraphs as well, however they do not allow the complete [[SDMX>>doc:sdmx:Glossary.Statistical data and metadata exchange.WebHome]] definition to be automatically deduced from the [[VTL>>doc:sdmx:Glossary.Validation and transformation language.WebHome]] definition, more than all because the former typically contains additional information in respect to the latter. For example, the definition of a [[SDMX>>doc:sdmx:Glossary.Statistical data and metadata exchange.WebHome]] [[DSD>>doc:sdmx:Glossary.Data structure definition.WebHome]] includes also some mandatory information not available in [[VTL>>doc:sdmx:Glossary.Validation and transformation language.WebHome]] (like the [[concept scheme>>doc:sdmx:Glossary.Concept scheme.WebHome]] to which the [[SDMX>>doc:sdmx:Glossary.Statistical data and metadata exchange.WebHome]] [[components>>doc:sdmx:Glossary.Component.WebHome]] refer, the assignmentStatus and attributeRelationship for the DataAttributes and so on). Therefore the mapping methods from [[VTL>>doc:sdmx:Glossary.Validation and transformation language.WebHome]] to [[SDMX>>doc:sdmx:Glossary.Statistical data and metadata exchange.WebHome]] provide only a general guidance for generating [[SDMX>>doc:sdmx:Glossary.Statistical data and metadata exchange.WebHome]] definitions properly starting from the information available in [[VTL>>doc:sdmx:Glossary.Validation and transformation language.WebHome]], independently of how the [[SDMX>>doc:sdmx:Glossary.Statistical data and metadata exchange.WebHome]] definition it is actually generated (manually, automatically or part and part).
1276
1277 === 10.3.2 General mapping of VTL and SDMX data structures ===
1278
1279 This section makes reference to the [[VTL>>doc:sdmx:Glossary.Validation and transformation language.WebHome]] “Model for data and their structure”{{footnote}}See the VTL 2.0 User Manual{{/footnote}} and the correspondent [[SDMX>>doc:sdmx:Glossary.Statistical data and metadata exchange.WebHome]] “[[Data Structure Definition>>doc:sdmx:Glossary.Data structure definition.WebHome]]”{{footnote}}See the SDMX 2.1 Section 2 – Information Model{{/footnote}}
1280
1281 The main type of [[artefact>>doc:sdmx:Glossary.Artefact.WebHome]] that the [[VTL>>doc:sdmx:Glossary.Validation and transformation language.WebHome]] can manipulate is the [[VTL>>doc:sdmx:Glossary.Validation and transformation language.WebHome]] [[Data Set>>doc:sdmx:Glossary.Data set.WebHome]], which in general is (% style="color:#e74c3c" %)mapped(%%) to the [[SDMX>>doc:sdmx:Glossary.Statistical data and metadata exchange.WebHome]] [[Dataflow>>doc:sdmx:Glossary.Dataflow.WebHome]]. This means that a [[VTL>>doc:sdmx:Glossary.Validation and transformation language.WebHome]] Transformation, in the [[SDMX>>doc:sdmx:Glossary.Statistical data and metadata exchange.WebHome]] context, expresses the algorithm for calculating a derived [[Dataflow>>doc:sdmx:Glossary.Dataflow.WebHome]] starting from some already existing [[Dataflows>>doc:sdmx:Glossary.Dataflow.WebHome]] (either collected or derived).{{footnote}}Besides the mapping between one SDMX Dataflow and one VTL Data Set, it is also possible to map distinct parts of a SDMX Dataflow to different VTL Data Set, as explained in a following paragraph.{{/footnote}}
1282
1283 While the [[VTL>>doc:sdmx:Glossary.Validation and transformation language.WebHome]] Transformations are defined in term of [[Dataflow>>doc:sdmx:Glossary.Dataflow.WebHome]] definitions, they are assumed to be executed on instances of such [[Dataflows>>doc:sdmx:Glossary.Dataflow.WebHome]], provided at runtime to the [[VTL>>doc:sdmx:Glossary.Validation and transformation language.WebHome]] engine (the mechanism for identifying the instances to be processed are not part of the [[VTL>>doc:sdmx:Glossary.Validation and transformation language.WebHome]] specifications and depend on the implementation of the [[VTL>>doc:sdmx:Glossary.Validation and transformation language.WebHome]]-based systems). As already said, the [[SDMX>>doc:sdmx:Glossary.Statistical data and metadata exchange.WebHome]] [[Datasets>>doc:sdmx:Glossary.Data set.WebHome]] are instances of [[SDMX>>doc:sdmx:Glossary.Statistical data and metadata exchange.WebHome]] [[Dataflows>>doc:sdmx:Glossary.Dataflow.WebHome]], therefore a [[VTL>>doc:sdmx:Glossary.Validation and transformation language.WebHome]] Transformation defined on some [[SDMX>>doc:sdmx:Glossary.Statistical data and metadata exchange.WebHome]] [[Dataflows>>doc:sdmx:Glossary.Dataflow.WebHome]] can be applied on some corresponding [[SDMX>>doc:sdmx:Glossary.Statistical data and metadata exchange.WebHome]] [[Datasets>>doc:sdmx:Glossary.Data set.WebHome]].
1284
1285 A [[VTL>>doc:sdmx:Glossary.Validation and transformation language.WebHome]] [[Data Set>>doc:sdmx:Glossary.Data set.WebHome]] is structured by one and just one Data Structure and a [[VTL>>doc:sdmx:Glossary.Validation and transformation language.WebHome]] Data Structure can structure any number of [[Data Sets>>doc:sdmx:Glossary.Data set.WebHome]]. Correspondingly, in the [[SDMX>>doc:sdmx:Glossary.Statistical data and metadata exchange.WebHome]] context a [[SDMX>>doc:sdmx:Glossary.Statistical data and metadata exchange.WebHome]] [[Dataflow>>doc:sdmx:Glossary.Dataflow.WebHome]] is structured by one and just one DataStructureDefinition and one DataStructureDefinition can structure any number of [[Dataflows>>doc:sdmx:Glossary.Dataflow.WebHome]].
1286
1287 A [[VTL>>doc:sdmx:Glossary.Validation and transformation language.WebHome]] [[Data Set>>doc:sdmx:Glossary.Data set.WebHome]] has a Data Structure made of [[Components>>doc:sdmx:Glossary.Component.WebHome]], which in turn can be Identifiers, [[Measures>>doc:sdmx:Glossary.Measure.WebHome]] and [[Attributes>>doc:sdmx:Glossary.Attribute.WebHome]]. Similarly, a [[SDMX>>doc:sdmx:Glossary.Statistical data and metadata exchange.WebHome]] DataflowDefinition has a DataStructureDefinition made of [[components>>doc:sdmx:Glossary.Component.WebHome]] that can be DimensionComponents, PrimaryMeasure and DataAttributes. In turn, a [[SDMX>>doc:sdmx:Glossary.Statistical data and metadata exchange.WebHome]] DimensionComponent can be a [[Dimension>>doc:sdmx:Glossary.Dimension.WebHome]], a TimeDimension or a MeasureDimension. Correspondingly, in the [[SDMX>>doc:sdmx:Glossary.Statistical data and metadata exchange.WebHome]] implementation of the [[VTL>>doc:sdmx:Glossary.Validation and transformation language.WebHome]], the [[VTL>>doc:sdmx:Glossary.Validation and transformation language.WebHome]] Identifiers can be (optionally) distinguished in three sub-classes (Simple Identifier, Time Identifier, [[Measure>>doc:sdmx:Glossary.Measure.WebHome]] Identifier) even if such a distinction is not evidenced in the [[VTL>>doc:sdmx:Glossary.Validation and transformation language.WebHome]] IM.
1288
1289 However, a [[VTL>>doc:sdmx:Glossary.Validation and transformation language.WebHome]] Data Structure can have any number of Identifiers, [[Measures>>doc:sdmx:Glossary.Measure.WebHome]] and [[Attributes>>doc:sdmx:Glossary.Attribute.WebHome]], while a [[SDMX>>doc:sdmx:Glossary.Statistical data and metadata exchange.WebHome]] 2.1 DataStructureDefinition can have any number of [[Dimensions>>doc:sdmx:Glossary.Dimension.WebHome]] and DataAttributes but just one PrimaryMeasure{{footnote}}The SDMX community is evaluating the opportunity of allowing more than one measure component in a DataStructureDefinition in the next SDMX major version.{{/footnote}}. This is due to a difference between [[SDMX>>doc:sdmx:Glossary.Statistical data and metadata exchange.WebHome]] 2.1 and [[VTL>>doc:sdmx:Glossary.Validation and transformation language.WebHome]] in the possible [[representation>>doc:sdmx:Glossary.Representation.WebHome]] methods of the data that contain more [[measures>>doc:sdmx:Glossary.Measure.WebHome]].
1290
1291 As for [[SDMX>>doc:sdmx:Glossary.Statistical data and metadata exchange.WebHome]], because the data structure cannot contain more than one [[measure>>doc:sdmx:Glossary.Measure.WebHome]] [[component>>doc:sdmx:Glossary.Component.WebHome]] (i.e., the primaryMeasure), the [[representation>>doc:sdmx:Glossary.Representation.WebHome]] of data having more [[measures>>doc:sdmx:Glossary.Measure.WebHome]] is possible only by means of a particular [[dimension>>doc:sdmx:Glossary.Dimension.WebHome]], called MeasureDimension, which is aimed at containing the name of the [[measure>>doc:sdmx:Glossary.Measure.WebHome]] (% style="color:#e74c3c" %)concepts(%%), so that for each observation the value contained in the PrimaryMeasure [[component>>doc:sdmx:Glossary.Component.WebHome]] is the value of the [[measure>>doc:sdmx:Glossary.Measure.WebHome]] (% style="color:#e74c3c" %)concept(%%) reported in the MeasureDimension [[component>>doc:sdmx:Glossary.Component.WebHome]].
1292
1293 Instead [[VTL>>doc:sdmx:Glossary.Validation and transformation language.WebHome]] allows either the method above (an identifier containing the name of the [[measure>>doc:sdmx:Glossary.Measure.WebHome]] together with just one [[measure>>doc:sdmx:Glossary.Measure.WebHome]] [[component>>doc:sdmx:Glossary.Component.WebHome]]) or a more generic method that consists in defining more [[measure>>doc:sdmx:Glossary.Measure.WebHome]] [[components>>doc:sdmx:Glossary.Component.WebHome]] in the data structure, one for each [[measure>>doc:sdmx:Glossary.Measure.WebHome]].
1294
1295 Therefore for multi-[[measure>>doc:sdmx:Glossary.Measure.WebHome]] data more mapping options are possible, as described in more detail in the following sections.
1296
1297 === 10.3.3 Mapping from SDMX to VTL data structures ===
1298
1299 ==== 10.3.3.1 Basic Mapping** ** ====
1300
1301 The main mapping method from [[SDMX>>doc:sdmx:Glossary.Statistical data and metadata exchange.WebHome]] to [[VTL>>doc:sdmx:Glossary.Validation and transformation language.WebHome]] is called **Basic **mapping. This is considered as the default mapping method and is applied unless a different method is specified through the VtlMappingScheme and VtlDataflowMapping classes.
1302
1303 When transforming **from [[SDMX>>doc:sdmx:Glossary.Statistical data and metadata exchange.WebHome]] to [[VTL>>doc:sdmx:Glossary.Validation and transformation language.WebHome]]**, this method consists in leaving the [[components>>doc:sdmx:Glossary.Component.WebHome]] unchanged and maintaining their names and roles, according to the following table:
1304
1305 (% style="width:636.294px" %)
1306 |(% style="width:286px" %)**SDMX**|(% style="width:347px" %)**VTL**
1307 |(% style="width:286px" %)[[Dimension>>doc:sdmx:Glossary.Dimension.WebHome]]|(% style="width:347px" %)(Simple) Identifier
1308 |(% style="width:286px" %)Time [[Dimension>>doc:sdmx:Glossary.Dimension.WebHome]]|(% style="width:347px" %)(Time) Identifier
1309 |(% style="width:286px" %)[[Measure>>doc:sdmx:Glossary.Measure.WebHome]] [[Dimension>>doc:sdmx:Glossary.Dimension.WebHome]]|(% style="width:347px" %)([[Measure>>doc:sdmx:Glossary.Measure.WebHome]]) Identifier
1310 |(% style="width:286px" %)Primary [[Measure>>doc:sdmx:Glossary.Measure.WebHome]]|(% style="width:347px" %)[[Measure>>doc:sdmx:Glossary.Measure.WebHome]]
1311 |(% style="width:286px" %)Data [[Attribute>>doc:sdmx:Glossary.Attribute.WebHome]]|(% style="width:347px" %)[[Attribute>>doc:sdmx:Glossary.Attribute.WebHome]]
1312
1313 According to this method, the resulting [[VTL>>doc:sdmx:Glossary.Validation and transformation language.WebHome]] structures are always mono-[[measure>>doc:sdmx:Glossary.Measure.WebHome]] (i.e., they have just one [[measure>>doc:sdmx:Glossary.Measure.WebHome]] [[component>>doc:sdmx:Glossary.Component.WebHome]]) and their [[Measure>>doc:sdmx:Glossary.Measure.WebHome]] is the [[SDMX>>doc:sdmx:Glossary.Statistical data and metadata exchange.WebHome]] PrimaryMeasure. Nevertheless, if the [[SDMX>>doc:sdmx:Glossary.Statistical data and metadata exchange.WebHome]] data structure has a MeasureDimension, which can convey the name of one or more [[measure>>doc:sdmx:Glossary.Measure.WebHome]] (% style="color:#e74c3c" %)concepts(%%), such unique [[measure>>doc:sdmx:Glossary.Measure.WebHome]] [[component>>doc:sdmx:Glossary.Component.WebHome]] can contain the value of more (conceptual) [[measures>>doc:sdmx:Glossary.Measure.WebHome]] (one for each observation).
1314
1315 As for the [[SDMX>>doc:sdmx:Glossary.Statistical data and metadata exchange.WebHome]] DataAttributes, in [[VTL>>doc:sdmx:Glossary.Validation and transformation language.WebHome]] they are all considered “at data point / observation (% style="color:#e74c3c" %)level(%%)” (i.e. dependent on all the [[VTL>>doc:sdmx:Glossary.Validation and transformation language.WebHome]] Identifiers), because [[VTL>>doc:sdmx:Glossary.Validation and transformation language.WebHome]] does not have the [[SDMX>>doc:sdmx:Glossary.Statistical data and metadata exchange.WebHome]] AttributeRelationships, which defines the construct to which the DataAttribute is related (e.g. observation, [[dimension>>doc:sdmx:Glossary.Dimension.WebHome]] or set or group of [[dimensions>>doc:sdmx:Glossary.Dimension.WebHome]], whole [[data set>>doc:sdmx:Glossary.Data set.WebHome]]).
1316
1317 With the Basic mapping, one [[SDMX>>doc:sdmx:Glossary.Statistical data and metadata exchange.WebHome]] observation generates one [[VTL>>doc:sdmx:Glossary.Validation and transformation language.WebHome]] data point.
1318
1319 ==== 10.3.3.2 Pivot Mapping ====
1320
1321 An alternative mapping method from [[SDMX>>doc:sdmx:Glossary.Statistical data and metadata exchange.WebHome]] to [[VTL>>doc:sdmx:Glossary.Validation and transformation language.WebHome]] is the **Pivot **mapping, which is different from the Basic method only for the [[SDMX>>doc:sdmx:Glossary.Statistical data and metadata exchange.WebHome]] data structures that contain a MeasureDimension, which are (% style="color:#e74c3c" %)mapped(%%) to multi-[[measure>>doc:sdmx:Glossary.Measure.WebHome]] [[VTL>>doc:sdmx:Glossary.Validation and transformation language.WebHome]] data structures.
1322
1323 The [[SDMX>>doc:sdmx:Glossary.Statistical data and metadata exchange.WebHome]] structures that do not contain a MeasureDimension are (% style="color:#e74c3c" %)mapped(%%) like in the Basic mapping (see the previous paragraph).
1324
1325 The [[SDMX>>doc:sdmx:Glossary.Statistical data and metadata exchange.WebHome]] structures that contain a MeasureDimension are (% style="color:#e74c3c" %)mapped(%%) as follows (this mapping is equivalent to a pivoting operation):
1326
1327 * A [[SDMX>>doc:sdmx:Glossary.Statistical data and metadata exchange.WebHome]] simple [[dimension>>doc:sdmx:Glossary.Dimension.WebHome]] becomes a [[VTL>>doc:sdmx:Glossary.Validation and transformation language.WebHome]] (simple) identifier and a [[SDMX>>doc:sdmx:Glossary.Statistical data and metadata exchange.WebHome]] TimeDimension becomes a [[VTL>>doc:sdmx:Glossary.Validation and transformation language.WebHome]] (time) identifier;
1328 * Each possible (% style="color:#e74c3c" %)Concept(%%) Cj of the [[SDMX>>doc:sdmx:Glossary.Statistical data and metadata exchange.WebHome]] MeasureDimension is (% style="color:#e74c3c" %)mapped(%%) to a [[VTL>>doc:sdmx:Glossary.Validation and transformation language.WebHome]] [[Measure>>doc:sdmx:Glossary.Measure.WebHome]], having the same name as the [[SDMX>>doc:sdmx:Glossary.Statistical data and metadata exchange.WebHome]] (% style="color:#e74c3c" %)Concept(%%) (i.e. Cj); the [[VTL>>doc:sdmx:Glossary.Validation and transformation language.WebHome]] [[Measure>>doc:sdmx:Glossary.Measure.WebHome]] Cj is a new [[VTL>>doc:sdmx:Glossary.Validation and transformation language.WebHome]] [[component>>doc:sdmx:Glossary.Component.WebHome]] even if the [[SDMX>>doc:sdmx:Glossary.Statistical data and metadata exchange.WebHome]] data structure has not such a [[Component>>doc:sdmx:Glossary.Component.WebHome]];
1329 * The [[SDMX>>doc:sdmx:Glossary.Statistical data and metadata exchange.WebHome]] MeasureDimension is not (% style="color:#e74c3c" %)mapped(%%) to [[VTL>>doc:sdmx:Glossary.Validation and transformation language.WebHome]] (it disappears in the [[VTL>>doc:sdmx:Glossary.Validation and transformation language.WebHome]] Data Structure);
1330 * The [[SDMX>>doc:sdmx:Glossary.Statistical data and metadata exchange.WebHome]] PrimaryMeasure is not (% style="color:#e74c3c" %)mapped(%%) to [[VTL>>doc:sdmx:Glossary.Validation and transformation language.WebHome]] as well (it disappears in the [[VTL>>doc:sdmx:Glossary.Validation and transformation language.WebHome]] Data Structure);
1331 * A [[SDMX>>doc:sdmx:Glossary.Statistical data and metadata exchange.WebHome]] DataAttribute is (% style="color:#e74c3c" %)mapped(%%) in different ways according to its AttributeRelationship:
1332 ** If, according to the [[SDMX>>doc:sdmx:Glossary.Statistical data and metadata exchange.WebHome]] AttributeRelationship, the values of the DataAttribute do not depend on the values of the MeasureDimension, the [[SDMX>>doc:sdmx:Glossary.Statistical data and metadata exchange.WebHome]] DataAttribute becomes a [[VTL>>doc:sdmx:Glossary.Validation and transformation language.WebHome]] [[Attribute>>doc:sdmx:Glossary.Attribute.WebHome]] having the same name. This happens if the AttributeRelationship is not specified (i.e. the DataAttribute does not depend on any DimensionComponent and therefore is at [[data set>>doc:sdmx:Glossary.Data set.WebHome]] (% style="color:#e74c3c" %)level(%%)), or if it refers to a set (or a group) of [[dimensions>>doc:sdmx:Glossary.Dimension.WebHome]] which does not include the MeasureDimension;
1333 ** Otherwise if, according to the [[SDMX>>doc:sdmx:Glossary.Statistical data and metadata exchange.WebHome]] AttributeRelationship, the values of the DataAttribute depend on the MeasureDimension, the [[SDMX>>doc:sdmx:Glossary.Statistical data and metadata exchange.WebHome]] DataAttribute is (% style="color:#e74c3c" %)mapped(%%) to one [[VTL>>doc:sdmx:Glossary.Validation and transformation language.WebHome]] [[Attribute>>doc:sdmx:Glossary.Attribute.WebHome]] for each possible (% style="color:#e74c3c" %)Concept(%%) of the [[SDMX>>doc:sdmx:Glossary.Statistical data and metadata exchange.WebHome]] MeasureDimension; by default, the names of the [[VTL>>doc:sdmx:Glossary.Validation and transformation language.WebHome]] [[Attributes>>doc:sdmx:Glossary.Attribute.WebHome]] are obtained by concatenating the name of the [[SDMX>>doc:sdmx:Glossary.Statistical data and metadata exchange.WebHome]] DataAttribute and the names of the correspondent
1334
1335 (% style="color:#e74c3c" %)Concept(%%) of the MeasureDimension separated by underscore; for example, if the [[SDMX>>doc:sdmx:Glossary.Statistical data and metadata exchange.WebHome]] DataAttribute is named DA and the possible (% style="color:#e74c3c" %)concepts(%%) of the [[SDMX>>doc:sdmx:Glossary.Statistical data and metadata exchange.WebHome]] MeasureDimension are named C1, C2, …, Cn, then the corresponding [[VTL>>doc:sdmx:Glossary.Validation and transformation language.WebHome]] [[Attributes>>doc:sdmx:Glossary.Attribute.WebHome]] will be named DA_C1, DA_C2, …, DA_Cn (if different names are desired, they can be achieved afterwards by renaming the [[Attributes>>doc:sdmx:Glossary.Attribute.WebHome]] through [[VTL>>doc:sdmx:Glossary.Validation and transformation language.WebHome]] operators). o Like in the Basic mapping, the resulting [[VTL>>doc:sdmx:Glossary.Validation and transformation language.WebHome]] [[Attributes>>doc:sdmx:Glossary.Attribute.WebHome]] are considered as dependent on all the [[VTL>>doc:sdmx:Glossary.Validation and transformation language.WebHome]] identifiers (i.e. “at data point / observation (% style="color:#e74c3c" %)level(%%)”), because [[VTL>>doc:sdmx:Glossary.Validation and transformation language.WebHome]] does not have the [[SDMX>>doc:sdmx:Glossary.Statistical data and metadata exchange.WebHome]] notion of [[Attribute>>doc:sdmx:Glossary.Attribute.WebHome]] Relationship.
1336
1337 The summary mapping table of the “pivot” mapping from [[SDMX>>doc:sdmx:Glossary.Statistical data and metadata exchange.WebHome]] to [[VTL>>doc:sdmx:Glossary.Validation and transformation language.WebHome]] for the [[SDMX>>doc:sdmx:Glossary.Statistical data and metadata exchange.WebHome]] data structures that contain a MeasureDimension is the following:
1338
1339 (% style="width:941.294px" %)
1340 |(% style="width:441px" %)**SDMX**|(% style="width:497px" %)**VTL**
1341 |(% style="width:441px" %)[[Dimension>>doc:sdmx:Glossary.Dimension.WebHome]]|(% style="width:497px" %)(Simple) Identifier
1342 |(% style="width:441px" %)TimeDimension|(% style="width:497px" %)(Time) Identifier
1343 |(% style="width:441px" %)MeasureDimension & PrimaryMeasure|(% style="width:497px" %)One [[Measure>>doc:sdmx:Glossary.Measure.WebHome]] for each (% style="color:#e74c3c" %)Concept(%%) of the [[SDMX>>doc:sdmx:Glossary.Statistical data and metadata exchange.WebHome]] [[Measure>>doc:sdmx:Glossary.Measure.WebHome]] [[Dimension>>doc:sdmx:Glossary.Dimension.WebHome]]
1344 |(% style="width:441px" %)DataAttribute not depending on the MeasureDimension|(% style="width:497px" %)[[Attribute>>doc:sdmx:Glossary.Attribute.WebHome]]
1345 |(% style="width:441px" %)DataAttribute depending on the MeasureDimension|(% style="width:497px" %)One [[Attribute>>doc:sdmx:Glossary.Attribute.WebHome]] for each (% style="color:#e74c3c" %)Concept(%%) of the [[SDMX>>doc:sdmx:Glossary.Statistical data and metadata exchange.WebHome]] [[Measure>>doc:sdmx:Glossary.Measure.WebHome]] [[Dimension>>doc:sdmx:Glossary.Dimension.WebHome]]
1346
1347 Using this mapping method, the [[components>>doc:sdmx:Glossary.Component.WebHome]] of the data structure can change in the conversion from [[SDMX>>doc:sdmx:Glossary.Statistical data and metadata exchange.WebHome]] to [[VTL>>doc:sdmx:Glossary.Validation and transformation language.WebHome]] and it must be taken into account that the [[VTL>>doc:sdmx:Glossary.Validation and transformation language.WebHome]] statements can reference only the [[components>>doc:sdmx:Glossary.Component.WebHome]] of the resulting [[VTL>>doc:sdmx:Glossary.Validation and transformation language.WebHome]] data structure.
1348
1349 At observation / data point (% style="color:#e74c3c" %)level(%%), calling Cj (j=1, … n) the j^^th^^ (% style="color:#e74c3c" %)Concept(%%) of the MeasureDimension:
1350
1351 * The set of [[SDMX>>doc:sdmx:Glossary.Statistical data and metadata exchange.WebHome]] observations having the same values for all the [[Dimensions>>doc:sdmx:Glossary.Dimension.WebHome]] except than the MeasureDimension become one multi-[[measure>>doc:sdmx:Glossary.Measure.WebHome]] [[VTL>>doc:sdmx:Glossary.Validation and transformation language.WebHome]] Data Point, having one [[Measure>>doc:sdmx:Glossary.Measure.WebHome]] for each (% style="color:#e74c3c" %)Concept(%%) Cj of the [[SDMX>>doc:sdmx:Glossary.Statistical data and metadata exchange.WebHome]] MeasureDimension;
1352 * The values of the [[SDMX>>doc:sdmx:Glossary.Statistical data and metadata exchange.WebHome]] simple [[Dimensions>>doc:sdmx:Glossary.Dimension.WebHome]], TimeDimension and DataAttributes not depending on the MeasureDimension (these [[components>>doc:sdmx:Glossary.Component.WebHome]] by definition have always the same values for all the observations of the set above) become the values of the corresponding [[VTL>>doc:sdmx:Glossary.Validation and transformation language.WebHome]] (simple) Identifiers, (time) Identifier and [[Attributes>>doc:sdmx:Glossary.Attribute.WebHome]].
1353 * The value of the PrimaryMeasure of the [[SDMX>>doc:sdmx:Glossary.Statistical data and metadata exchange.WebHome]] observation belonging to the set above and having MeasureDimension=Cj becomes the value of the [[VTL>>doc:sdmx:Glossary.Validation and transformation language.WebHome]] [[Measure>>doc:sdmx:Glossary.Measure.WebHome]] Cj
1354 * For the [[SDMX>>doc:sdmx:Glossary.Statistical data and metadata exchange.WebHome]] DataAttributes depending on the MeasureDimension, the value of the DataAttribute DA of the [[SDMX>>doc:sdmx:Glossary.Statistical data and metadata exchange.WebHome]] observation belonging to the set above and having MeasureDimension=Cj becomes the value of the [[VTL>>doc:sdmx:Glossary.Validation and transformation language.WebHome]] [[Attribute>>doc:sdmx:Glossary.Attribute.WebHome]] DA_Cj
1355
1356 ==== 10.3.3.3 From SDMX DataAttributes to VTL Measures ====
1357
1358 * In some cases it may happen that the DataAttributes of the [[SDMX>>doc:sdmx:Glossary.Statistical data and metadata exchange.WebHome]] DataStructure need to be managed as [[Measures>>doc:sdmx:Glossary.Measure.WebHome]] in [[VTL>>doc:sdmx:Glossary.Validation and transformation language.WebHome]]. Therefore, a variant of both the methods above consists in transforming all the [[SDMX>>doc:sdmx:Glossary.Statistical data and metadata exchange.WebHome]] DataAttributes in [[VTL>>doc:sdmx:Glossary.Validation and transformation language.WebHome]] [[Measures>>doc:sdmx:Glossary.Measure.WebHome]]. When DataAttributes are converted to [[Measures>>doc:sdmx:Glossary.Measure.WebHome]], the two methods above are called Basic_A2M and Pivot_A2M (the suffix “A2M” stands for [[Attributes>>doc:sdmx:Glossary.Attribute.WebHome]] to [[Measures>>doc:sdmx:Glossary.Measure.WebHome]]). Obviously, the resulting [[VTL>>doc:sdmx:Glossary.Validation and transformation language.WebHome]] data structure is, in general, multi-[[measure>>doc:sdmx:Glossary.Measure.WebHome]] and does not contain [[Attributes>>doc:sdmx:Glossary.Attribute.WebHome]].
1359
1360 The Basic_A2M and Pivot_A2M behaves respectively like the Basic and Pivot methods, except that the final [[VTL>>doc:sdmx:Glossary.Validation and transformation language.WebHome]] [[components>>doc:sdmx:Glossary.Component.WebHome]], which according to the Basic and Pivot methods would have had the role of [[Attribute>>doc:sdmx:Glossary.Attribute.WebHome]], assume instead the role of [[Measure>>doc:sdmx:Glossary.Measure.WebHome]].
1361
1362 Proper [[VTL>>doc:sdmx:Glossary.Validation and transformation language.WebHome]] features allow changing the role of specific [[attributes>>doc:sdmx:Glossary.Attribute.WebHome]] even after the [[SDMX>>doc:sdmx:Glossary.Statistical data and metadata exchange.WebHome]] to [[VTL>>doc:sdmx:Glossary.Validation and transformation language.WebHome]] mapping: they can be useful when only some of the DataAttributes need to be managed as [[VTL>>doc:sdmx:Glossary.Validation and transformation language.WebHome]] [[Measures>>doc:sdmx:Glossary.Measure.WebHome]].
1363
1364 === 10.3.4 Mapping from VTL to SDMX data structures ===
1365
1366 ==== 10.3.4.1 Basic Mapping** ** ====
1367
1368 The main mapping method **from [[VTL>>doc:sdmx:Glossary.Validation and transformation language.WebHome]] to [[SDMX>>doc:sdmx:Glossary.Statistical data and metadata exchange.WebHome]]** is called **Basic **mapping as well.
1369
1370 This is considered as the default mapping method and is applied unless a different method is specified through the VtlMappingScheme and VtlDataflowMapping classes.
1371
1372 The method consists in leaving the [[components>>doc:sdmx:Glossary.Component.WebHome]] unchanged and maintaining their names and roles in [[SDMX>>doc:sdmx:Glossary.Statistical data and metadata exchange.WebHome]], according to the following mapping table, which is the same as the basic mapping from [[SDMX>>doc:sdmx:Glossary.Statistical data and metadata exchange.WebHome]] to [[VTL>>doc:sdmx:Glossary.Validation and transformation language.WebHome]], only seen in the opposite direction.
1373
1374 This mapping method cannot be applied for [[SDMX>>doc:sdmx:Glossary.Statistical data and metadata exchange.WebHome]] 2.1 if the [[VTL>>doc:sdmx:Glossary.Validation and transformation language.WebHome]] data structure has more than one [[measure>>doc:sdmx:Glossary.Measure.WebHome]] [[component>>doc:sdmx:Glossary.Component.WebHome]], given that the [[SDMX>>doc:sdmx:Glossary.Statistical data and metadata exchange.WebHome]] 2.1 DataStructureDefinition allows just one [[measure>>doc:sdmx:Glossary.Measure.WebHome]] [[component>>doc:sdmx:Glossary.Component.WebHome]] (the PrimaryMeasure). In this case it becomes mandatory to specify a different mapping method through the VtlMappingScheme and VtlDataflowMapping classes.{{footnote}}If future SDMX major versions will allow multi-measures data structures, this method is expected to become applicable even if the VTL data structure has more than one measure{{/footnote}}
1375
1376 Please note that the [[VTL>>doc:sdmx:Glossary.Validation and transformation language.WebHome]] [[measures>>doc:sdmx:Glossary.Measure.WebHome]] can have any name while in [[SDMX>>doc:sdmx:Glossary.Statistical data and metadata exchange.WebHome]] 2.1 the MeasureComponent has the mandatory name “obs_value”, therefore the name of the [[VTL>>doc:sdmx:Glossary.Validation and transformation language.WebHome]] [[measure>>doc:sdmx:Glossary.Measure.WebHome]] name must become “obs_value” in [[SDMX>>doc:sdmx:Glossary.Statistical data and metadata exchange.WebHome]] 2.1.
1377
1378 Mapping table:
1379
1380 (% style="width:592.294px" %)
1381 |(% style="width:253px" %)**VTL**|(% style="width:336px" %)**SDMX**
1382 |(% style="width:253px" %)(Simple) Identifier|(% style="width:336px" %)[[Dimension>>doc:sdmx:Glossary.Dimension.WebHome]]
1383 |(% style="width:253px" %)(Time) Identifier|(% style="width:336px" %)TimeDimension
1384 |(% style="width:253px" %)([[Measure>>doc:sdmx:Glossary.Measure.WebHome]]) Identifier|(% style="width:336px" %)MeasureDimension
1385 |(% style="width:253px" %)[[Measure>>doc:sdmx:Glossary.Measure.WebHome]]|(% style="width:336px" %)PrimaryMeasure
1386 |(% style="width:253px" %)[[Attribute>>doc:sdmx:Glossary.Attribute.WebHome]]|(% style="width:336px" %)DataAttribute
1387
1388 If the distinction between simple identifier, time identifier and [[measure>>doc:sdmx:Glossary.Measure.WebHome]] identifier is not maintained in the [[VTL>>doc:sdmx:Glossary.Validation and transformation language.WebHome]] environment, the classification between [[Dimension>>doc:sdmx:Glossary.Dimension.WebHome]], TimeDimension and MeasureDimension exists only in [[SDMX>>doc:sdmx:Glossary.Statistical data and metadata exchange.WebHome]], as declared in the relevant DataStructureDefinition.
1389
1390 Regarding the [[Attributes>>doc:sdmx:Glossary.Attribute.WebHome]], because [[VTL>>doc:sdmx:Glossary.Validation and transformation language.WebHome]] considers all of them “at observation (% style="color:#e74c3c" %)level(%%)”, the corresponding [[SDMX>>doc:sdmx:Glossary.Statistical data and metadata exchange.WebHome]] DataAttributes should be put “at observation (% style="color:#e74c3c" %)level(%%)” as well (AttributeRelationships referred to the PrimaryMeasure), unless some other information about their AttributeRelationship is available.
1391
1392 Note that the basic mappings in the two directions (from [[SDMX>>doc:sdmx:Glossary.Statistical data and metadata exchange.WebHome]] 2.1 to [[VTL>>doc:sdmx:Glossary.Validation and transformation language.WebHome]] 2.0 and vice-versa) are (almost completely) reversible. In fact, if a [[SDMX>>doc:sdmx:Glossary.Statistical data and metadata exchange.WebHome]] 2.1 structure is (% style="color:#e74c3c" %)mapped(%%) to a [[VTL>>doc:sdmx:Glossary.Validation and transformation language.WebHome]] structure and then the latter is (% style="color:#e74c3c" %)mapped(%%) back to [[SDMX>>doc:sdmx:Glossary.Statistical data and metadata exchange.WebHome]] 2.1, the resulting data structure is like the original one (apart for the AttributeRelationship, that can be different if the original [[SDMX>>doc:sdmx:Glossary.Statistical data and metadata exchange.WebHome]] 2.1 structure contains DataAttributes that are not at observation (% style="color:#e74c3c" %)level(%%)). In reverse order, if a [[VTL>>doc:sdmx:Glossary.Validation and transformation language.WebHome]] 2.0 mono-[[measure>>doc:sdmx:Glossary.Measure.WebHome]] structure is (% style="color:#e74c3c" %)mapped(%%) to [[SDMX>>doc:sdmx:Glossary.Statistical data and metadata exchange.WebHome]] 2.1 and then the latter is (% style="color:#e74c3c" %)mapped(%%) back to [[VTL>>doc:sdmx:Glossary.Validation and transformation language.WebHome]] 2.0, the original data structure is obtained (apart from the name of the [[VTL>>doc:sdmx:Glossary.Validation and transformation language.WebHome]] [[measure>>doc:sdmx:Glossary.Measure.WebHome]], that in [[SDMX>>doc:sdmx:Glossary.Statistical data and metadata exchange.WebHome]] 2.1 must become “obs_value”).
1393
1394 As said, the resulting [[SDMX>>doc:sdmx:Glossary.Statistical data and metadata exchange.WebHome]] definitions must be compliant with the [[SDMX>>doc:sdmx:Glossary.Statistical data and metadata exchange.WebHome]] consistency rules. For example, the [[SDMX>>doc:sdmx:Glossary.Statistical data and metadata exchange.WebHome]] [[DSD>>doc:sdmx:Glossary.Data structure definition.WebHome]] must have the assignmentStatus, which does not exist in [[VTL>>doc:sdmx:Glossary.Validation and transformation language.WebHome]], the AttributeRelationship for the DataAttributes and so on.
1395
1396 ==== 10.3.4.2 Unpivot Mapping ====
1397
1398 An alternative mapping method from [[VTL>>doc:sdmx:Glossary.Validation and transformation language.WebHome]] to [[SDMX>>doc:sdmx:Glossary.Statistical data and metadata exchange.WebHome]] is the **Unpivot **mapping.
1399
1400 Although this mapping method can be used in any case, it makes major sense in case the [[VTL>>doc:sdmx:Glossary.Validation and transformation language.WebHome]] data structure has more than one [[measure>>doc:sdmx:Glossary.Measure.WebHome]] [[component>>doc:sdmx:Glossary.Component.WebHome]] (multi-[[measures>>doc:sdmx:Glossary.Measure.WebHome]] [[VTL>>doc:sdmx:Glossary.Validation and transformation language.WebHome]] structure). For such [[VTL>>doc:sdmx:Glossary.Validation and transformation language.WebHome]] structures, in fact, the basic method cannot be applied, given that by maintaining the data structure unchanged the resulting [[SDMX>>doc:sdmx:Glossary.Statistical data and metadata exchange.WebHome]] data structure would have more than one [[measure>>doc:sdmx:Glossary.Measure.WebHome]] [[component>>doc:sdmx:Glossary.Component.WebHome]], which is not allowed by [[SDMX>>doc:sdmx:Glossary.Statistical data and metadata exchange.WebHome]] 2.1 (it allows just one [[measure>>doc:sdmx:Glossary.Measure.WebHome]] [[component>>doc:sdmx:Glossary.Component.WebHome]], the PrimaryMeasure, called “obs_value”).
1401
1402 The multi-[[measures>>doc:sdmx:Glossary.Measure.WebHome]] [[VTL>>doc:sdmx:Glossary.Validation and transformation language.WebHome]] structures have not a [[Measure>>doc:sdmx:Glossary.Measure.WebHome]] Identifier (because the [[Measures>>doc:sdmx:Glossary.Measure.WebHome]] are separate [[components>>doc:sdmx:Glossary.Component.WebHome]]) and need to be converted to [[SDMX>>doc:sdmx:Glossary.Statistical data and metadata exchange.WebHome]] [[dataflows>>doc:sdmx:Glossary.Dataflow.WebHome]] having an added MeasureDimension which disambiguates the multiple [[measures>>doc:sdmx:Glossary.Measure.WebHome]], and an added PrimaryMeasure, in which the [[measures>>doc:sdmx:Glossary.Measure.WebHome]]’ values are maintained.
1403
1404 The **unpivot** mapping behaves like follows:
1405
1406 * like in the basic mapping, a [[VTL>>doc:sdmx:Glossary.Validation and transformation language.WebHome]] (simple) identifier becomes a [[SDMX>>doc:sdmx:Glossary.Statistical data and metadata exchange.WebHome]] [[Dimension>>doc:sdmx:Glossary.Dimension.WebHome]] and a [[VTL>>doc:sdmx:Glossary.Validation and transformation language.WebHome]] (time) identifier becomes a [[SDMX>>doc:sdmx:Glossary.Statistical data and metadata exchange.WebHome]] TimeDimension (as said, a [[measure>>doc:sdmx:Glossary.Measure.WebHome]] identifier cannot exist in multi-[[measure>>doc:sdmx:Glossary.Measure.WebHome]] [[VTL>>doc:sdmx:Glossary.Validation and transformation language.WebHome]] structures);
1407 * a MeasureDimension [[component>>doc:sdmx:Glossary.Component.WebHome]] called “measure_name” is added to the [[SDMX>>doc:sdmx:Glossary.Statistical data and metadata exchange.WebHome]] DataStructure;
1408 * a PrimaryMeasure [[component>>doc:sdmx:Glossary.Component.WebHome]] called “obs_value” is added to the [[SDMX>>doc:sdmx:Glossary.Statistical data and metadata exchange.WebHome]] DataStructure;
1409 * each [[VTL>>doc:sdmx:Glossary.Validation and transformation language.WebHome]] [[Measure>>doc:sdmx:Glossary.Measure.WebHome]] is (% style="color:#e74c3c" %)mapped(%%) to a (% style="color:#e74c3c" %)Concept(%%) of the [[SDMX>>doc:sdmx:Glossary.Statistical data and metadata exchange.WebHome]] MeasureDimension having the same name as the [[VTL>>doc:sdmx:Glossary.Validation and transformation language.WebHome]] [[Measure>>doc:sdmx:Glossary.Measure.WebHome]] (therefore all the [[VTL>>doc:sdmx:Glossary.Validation and transformation language.WebHome]] [[Measure>>doc:sdmx:Glossary.Measure.WebHome]] [[Components>>doc:sdmx:Glossary.Component.WebHome]] do not originate [[Components>>doc:sdmx:Glossary.Component.WebHome]] in the [[SDMX>>doc:sdmx:Glossary.Statistical data and metadata exchange.WebHome]] DataStructure);
1410 * a [[VTL>>doc:sdmx:Glossary.Validation and transformation language.WebHome]] [[Attribute>>doc:sdmx:Glossary.Attribute.WebHome]] becomes a [[SDMX>>doc:sdmx:Glossary.Statistical data and metadata exchange.WebHome]] DataAttribute having AttributeRelationship referred to all the [[SDMX>>doc:sdmx:Glossary.Statistical data and metadata exchange.WebHome]] DimensionComponents including the TimeDimension and except the MeasureDimension.
1411
1412 The summary mapping table of the **unpivot** mapping method is the following:
1413
1414 (% style="width:904.294px" %)
1415 |(% style="width:291px" %)**VTL**|(% style="width:611px" %)**SDMX**
1416 |(% style="width:291px" %)(Simple) Identifier|(% style="width:611px" %)[[Dimension>>doc:sdmx:Glossary.Dimension.WebHome]]
1417 |(% style="width:291px" %)(Time) Identifier|(% style="width:611px" %)TimeDimension
1418 |(% style="width:291px" %)All [[Measure>>doc:sdmx:Glossary.Measure.WebHome]] [[Components>>doc:sdmx:Glossary.Component.WebHome]]|(% style="width:611px" %)(((
1419 MeasureDimension (having one [[Measure>>doc:sdmx:Glossary.Measure.WebHome]] (% style="color:#e74c3c" %)Concept(%%) for each [[VTL>>doc:sdmx:Glossary.Validation and transformation language.WebHome]] [[measure>>doc:sdmx:Glossary.Measure.WebHome]] [[component>>doc:sdmx:Glossary.Component.WebHome]]) & PrimaryMeasure
1420 )))
1421 |(% style="width:291px" %)[[Attribute>>doc:sdmx:Glossary.Attribute.WebHome]] |(% style="width:611px" %)(((
1422 DataAttribute depending on all [[SDMX>>doc:sdmx:Glossary.Statistical data and metadata exchange.WebHome]] [[Dimensions>>doc:sdmx:Glossary.Dimension.WebHome]] including the TimeDimension and except the MeasureDimension
1423 )))
1424
1425 At observation / data point (% style="color:#e74c3c" %)level(%%):
1426
1427 * a multi-[[measure>>doc:sdmx:Glossary.Measure.WebHome]] [[VTL>>doc:sdmx:Glossary.Validation and transformation language.WebHome]] Data Point becomes a set of [[SDMX>>doc:sdmx:Glossary.Statistical data and metadata exchange.WebHome]] observations, one for each [[VTL>>doc:sdmx:Glossary.Validation and transformation language.WebHome]] [[measure>>doc:sdmx:Glossary.Measure.WebHome]]
1428 * the values of the [[VTL>>doc:sdmx:Glossary.Validation and transformation language.WebHome]] identifiers become the values of the corresponding [[SDMX>>doc:sdmx:Glossary.Statistical data and metadata exchange.WebHome]] [[Dimensions>>doc:sdmx:Glossary.Dimension.WebHome]], for all the observations of the set above
1429 * the name of the j^^th^^ [[VTL>>doc:sdmx:Glossary.Validation and transformation language.WebHome]] [[measure>>doc:sdmx:Glossary.Measure.WebHome]] (e.g. “Cj”) becomes the value of the [[SDMX>>doc:sdmx:Glossary.Statistical data and metadata exchange.WebHome]] MeasureDimension of the j^^th^^ observation of the set (i.e. the (% style="color:#e74c3c" %)Concept(%%) Cj)
1430 * the value of the j^^th^^ [[VTL>>doc:sdmx:Glossary.Validation and transformation language.WebHome]] [[measure>>doc:sdmx:Glossary.Measure.WebHome]] becomes the value of the [[SDMX>>doc:sdmx:Glossary.Statistical data and metadata exchange.WebHome]] PrimaryMeasure of the j^^th^^ observation of the set
1431 * the values of the [[VTL>>doc:sdmx:Glossary.Validation and transformation language.WebHome]] [[Attributes>>doc:sdmx:Glossary.Attribute.WebHome]] become the values of the corresponding [[SDMX>>doc:sdmx:Glossary.Statistical data and metadata exchange.WebHome]] DataAttributes (in principle for all the observations of the set above)
1432
1433 If desired, this method can be applied also to mono-[[measure>>doc:sdmx:Glossary.Measure.WebHome]] [[VTL>>doc:sdmx:Glossary.Validation and transformation language.WebHome]] structures, provided that none of the [[VTL>>doc:sdmx:Glossary.Validation and transformation language.WebHome]] [[components>>doc:sdmx:Glossary.Component.WebHome]] has already the role of [[measure>>doc:sdmx:Glossary.Measure.WebHome]] identifier.
1434
1435 Like in the general case, a MeasureDimension [[component>>doc:sdmx:Glossary.Component.WebHome]] called “measure_name” would be added to the [[SDMX>>doc:sdmx:Glossary.Statistical data and metadata exchange.WebHome]] DataStructure and would have just one possible [[measure>>doc:sdmx:Glossary.Measure.WebHome]] (% style="color:#e74c3c" %)concept(%%), corresponding to the unique [[VTL>>doc:sdmx:Glossary.Validation and transformation language.WebHome]] [[measure>>doc:sdmx:Glossary.Measure.WebHome]]. The original [[VTL>>doc:sdmx:Glossary.Validation and transformation language.WebHome]] [[measure>>doc:sdmx:Glossary.Measure.WebHome]] [[component>>doc:sdmx:Glossary.Component.WebHome]] would not become a [[Component>>doc:sdmx:Glossary.Component.WebHome]] in the [[SDMX>>doc:sdmx:Glossary.Statistical data and metadata exchange.WebHome]] data structure. The value of the [[VTL>>doc:sdmx:Glossary.Validation and transformation language.WebHome]] [[measure>>doc:sdmx:Glossary.Measure.WebHome]] would be assigned to the [[SDMX>>doc:sdmx:Glossary.Statistical data and metadata exchange.WebHome]] PrimaryMeasure called “obs_value”.
1436
1437 In any case, the resulting [[SDMX>>doc:sdmx:Glossary.Statistical data and metadata exchange.WebHome]] definitions must be compliant with the [[SDMX>>doc:sdmx:Glossary.Statistical data and metadata exchange.WebHome]] consistency rules. For example, the possible (% style="color:#e74c3c" %)Concepts(%%) of the [[SDMX>>doc:sdmx:Glossary.Statistical data and metadata exchange.WebHome]] MeasureDimension need to be listed in a [[SDMX>>doc:sdmx:Glossary.Statistical data and metadata exchange.WebHome]] ConceptScheme, with proper id, agency and (% style="color:#e74c3c" %)version(%%); moreover, the [[SDMX>>doc:sdmx:Glossary.Statistical data and metadata exchange.WebHome]] [[DSD>>doc:sdmx:Glossary.Data structure definition.WebHome]] must have the assignmentStatus, which does not exist in [[VTL>>doc:sdmx:Glossary.Validation and transformation language.WebHome]], the attributeRelationship for the DataAttributes and so on.
1438
1439 ==== 10.3.4.3 From VTL Measures to SDMX Data Attributes** ** ====
1440
1441 For the multi-[[measure>>doc:sdmx:Glossary.Measure.WebHome]] [[VTL>>doc:sdmx:Glossary.Validation and transformation language.WebHome]] structures (having more than one [[Measure>>doc:sdmx:Glossary.Measure.WebHome]] [[Component>>doc:sdmx:Glossary.Component.WebHome]]), it may happen that the [[Measures>>doc:sdmx:Glossary.Measure.WebHome]] of the [[VTL>>doc:sdmx:Glossary.Validation and transformation language.WebHome]] Data Structure need to be managed as DataAttributes in [[SDMX>>doc:sdmx:Glossary.Statistical data and metadata exchange.WebHome]]. Therefore a third mapping method consists in transforming one [[VTL>>doc:sdmx:Glossary.Validation and transformation language.WebHome]] [[measure>>doc:sdmx:Glossary.Measure.WebHome]] in the [[SDMX>>doc:sdmx:Glossary.Statistical data and metadata exchange.WebHome]] primaryMeasure and all the other [[VTL>>doc:sdmx:Glossary.Validation and transformation language.WebHome]] [[Measures>>doc:sdmx:Glossary.Measure.WebHome]] in [[SDMX>>doc:sdmx:Glossary.Statistical data and metadata exchange.WebHome]] DataAttributes. This method is called M2A (“M2A” stands for “[[Measures>>doc:sdmx:Glossary.Measure.WebHome]] to DataAttributes”).
1442
1443 When applied to mono-[[measure>>doc:sdmx:Glossary.Measure.WebHome]] [[VTL>>doc:sdmx:Glossary.Validation and transformation language.WebHome]] structures (having one [[Measure>>doc:sdmx:Glossary.Measure.WebHome]] [[component>>doc:sdmx:Glossary.Component.WebHome]]), the M2A method behaves like the Basic mapping (the [[VTL>>doc:sdmx:Glossary.Validation and transformation language.WebHome]] [[Measure>>doc:sdmx:Glossary.Measure.WebHome]] [[component>>doc:sdmx:Glossary.Component.WebHome]] becomes the [[SDMX>>doc:sdmx:Glossary.Statistical data and metadata exchange.WebHome]] primary [[measure>>doc:sdmx:Glossary.Measure.WebHome]] “obs_value”, there is no additional [[VTL>>doc:sdmx:Glossary.Validation and transformation language.WebHome]] [[measure>>doc:sdmx:Glossary.Measure.WebHome]] to be converted to [[SDMX>>doc:sdmx:Glossary.Statistical data and metadata exchange.WebHome]] DataAttribute). Therefore the mapping table is the same as for the Basic method:
1444
1445 (% style="width:591.294px" %)
1446 |(% style="width:252px" %)**VTL**|(% style="width:336px" %)**SDMX**
1447 |(% style="width:252px" %)(Simple) Identifier|(% style="width:336px" %)[[Dimension>>doc:sdmx:Glossary.Dimension.WebHome]]
1448 |(% style="width:252px" %)(Time) Identifier|(% style="width:336px" %)TimeDimension
1449 |(% style="width:252px" %)([[Measure>>doc:sdmx:Glossary.Measure.WebHome]]) Identifier (if any)|(% style="width:336px" %)MeasureDimension
1450 |(% style="width:252px" %)[[Measure>>doc:sdmx:Glossary.Measure.WebHome]]|(% style="width:336px" %)PrimaryMeasure
1451 |(% style="width:252px" %)[[Attribute>>doc:sdmx:Glossary.Attribute.WebHome]]|(% style="width:336px" %)DataAttribute
1452
1453 For multi-[[measure>>doc:sdmx:Glossary.Measure.WebHome]] [[VTL>>doc:sdmx:Glossary.Validation and transformation language.WebHome]] structures (having more than one [[Measure>>doc:sdmx:Glossary.Measure.WebHome]] [[component>>doc:sdmx:Glossary.Component.WebHome]]), one [[VTL>>doc:sdmx:Glossary.Validation and transformation language.WebHome]] [[Measure>>doc:sdmx:Glossary.Measure.WebHome]] becomes the [[SDMX>>doc:sdmx:Glossary.Statistical data and metadata exchange.WebHome]] PrimaryMeasure while the other [[VTL>>doc:sdmx:Glossary.Validation and transformation language.WebHome]] [[Measures>>doc:sdmx:Glossary.Measure.WebHome]] maintain their names and values but assume the role of DataAttribute in [[SDMX>>doc:sdmx:Glossary.Statistical data and metadata exchange.WebHome]]. The choice of the [[VTL>>doc:sdmx:Glossary.Validation and transformation language.WebHome]] [[Measure>>doc:sdmx:Glossary.Measure.WebHome]] that correspond to the [[SDMX>>doc:sdmx:Glossary.Statistical data and metadata exchange.WebHome]] PrimaryMeasure is left to the definer of the [[SDMX>>doc:sdmx:Glossary.Statistical data and metadata exchange.WebHome]] [[data structure definition>>doc:sdmx:Glossary.Data structure definition.WebHome]].
1454
1455 Taking into account that the multi-[[measure>>doc:sdmx:Glossary.Measure.WebHome]] [[VTL>>doc:sdmx:Glossary.Validation and transformation language.WebHome]] structures do not have a [[measure>>doc:sdmx:Glossary.Measure.WebHome]] identifier, the mapping table is the following:
1456
1457 (% style="width:588.294px" %)
1458 |(% style="width:259px" %)**VTL**|(% style="width:326px" %)**SDMX**
1459 |(% style="width:259px" %)(Simple) Identifier|(% style="width:326px" %)[[Dimension>>doc:sdmx:Glossary.Dimension.WebHome]]
1460 |(% style="width:259px" %)(Time) Identifier|(% style="width:326px" %)TimeDimension
1461 |(% style="width:259px" %)One of the [[Measures>>doc:sdmx:Glossary.Measure.WebHome]]|(% style="width:326px" %)PrimaryMeasure
1462 |(% style="width:259px" %)Other [[Measures>>doc:sdmx:Glossary.Measure.WebHome]]|(% style="width:326px" %)DataAttribute
1463 |(% style="width:259px" %)[[Attribute>>doc:sdmx:Glossary.Attribute.WebHome]]|(% style="width:326px" %)DataAttribute
1464
1465 Even in this case, the resulting [[SDMX>>doc:sdmx:Glossary.Statistical data and metadata exchange.WebHome]] definitions must be compliant with the [[SDMX>>doc:sdmx:Glossary.Statistical data and metadata exchange.WebHome]] consistency rules. For example, the [[SDMX>>doc:sdmx:Glossary.Statistical data and metadata exchange.WebHome]] [[DSD>>doc:sdmx:Glossary.Data structure definition.WebHome]] must have the assignmentStatus, which does not exist in [[VTL>>doc:sdmx:Glossary.Validation and transformation language.WebHome]], the attributeRelationship for the DataAttributes and so on. In particular, the primaryMeasure of the [[SDMX>>doc:sdmx:Glossary.Statistical data and metadata exchange.WebHome]] 2.1 [[DSD>>doc:sdmx:Glossary.Data structure definition.WebHome]] must be called “obs_value” and must be one of the [[VTL>>doc:sdmx:Glossary.Validation and transformation language.WebHome]] [[Measures>>doc:sdmx:Glossary.Measure.WebHome]], chosen by the [[DSD>>doc:sdmx:Glossary.Data structure definition.WebHome]] definer.
1466
1467 === 10.3.5 Declaration of the mapping methods between data structures ===
1468
1469 In order to define and understand properly [[VTL>>doc:sdmx:Glossary.Validation and transformation language.WebHome]] transformations, the applied mapping methods must be specified in the [[SDMX>>doc:sdmx:Glossary.Statistical data and metadata exchange.WebHome]] [[structural metadata>>doc:sdmx:Glossary.Structural metadata.WebHome]]. If the default mapping method (Basic) is applied, no specification is needed.
1470
1471 A customized mapping can be defined through the VtlMappingScheme and VtlDataflowMapping classes (see the section of the [[SDMX>>doc:sdmx:Glossary.Statistical data and metadata exchange.WebHome]] IM relevant to the [[VTL>>doc:sdmx:Glossary.Validation and transformation language.WebHome]]). A VtlDataflowMapping allows specifying the mapping methods to be used for a specific [[dataflow>>doc:sdmx:Glossary.Dataflow.WebHome]], both in the direction from [[SDMX>>doc:sdmx:Glossary.Statistical data and metadata exchange.WebHome]] to [[VTL>>doc:sdmx:Glossary.Validation and transformation language.WebHome]] (toVtlMappingMethod) and from [[VTL>>doc:sdmx:Glossary.Validation and transformation language.WebHome]] to [[SDMX>>doc:sdmx:Glossary.Statistical data and metadata exchange.WebHome]] (fromVtlMappingMethod); in fact a VtlDataflowMapping associates the structured URN that identifies a [[SDMX>>doc:sdmx:Glossary.Statistical data and metadata exchange.WebHome]] [[dataflow>>doc:sdmx:Glossary.Dataflow.WebHome]] to its [[VTL>>doc:sdmx:Glossary.Validation and transformation language.WebHome]] alias and its mapping methods.
1472
1473 It is possible to specify the toVtlMappingMethod and fromVtlMappingMethod also for the conventional [[dataflow>>doc:sdmx:Glossary.Dataflow.WebHome]] called “generic_dataflow”: in this case the specified mapping methods are intended to become the default ones, overriding the “Basic” methods. In turn, the toVtlMappingMethod and fromVtlMappingMethod declared for a specific [[Dataflow>>doc:sdmx:Glossary.Dataflow.WebHome]] are intended to override the default ones for such a [[Dataflow>>doc:sdmx:Glossary.Dataflow.WebHome]].
1474
1475 The VtlMappingScheme is a container for zero or more VtlDataflowMapping (besides possible mappings to [[artefacts>>doc:sdmx:Glossary.Artefact.WebHome]] other than [[dataflows>>doc:sdmx:Glossary.Dataflow.WebHome]]).
1476
1477 === 10.3.6 Mapping dataflow subsets to distinct VTL data sets{{footnote}}The kind of mapping explained here works in combination with a SDMX specific naming convention that requires pre-processing before parsing the VTL expressions. As highlighted below, the identifiers of the VTL datasets are a shortcut of some specific VTL operators applied to the SDMX Dataflows. This is not safe to use outside an SDMX context, as the naming convention may have no meaning there.{{/footnote}} ===
1478
1479 Until now it as been assumed to (% style="color:#e74c3c" %)map(%%) one SMDX [[Dataflow>>doc:sdmx:Glossary.Dataflow.WebHome]] to one [[VTL>>doc:sdmx:Glossary.Validation and transformation language.WebHome]] [[dataset>>doc:sdmx:Glossary.Data set.WebHome]] and vice-versa. This mapping one-to-one is not mandatory according to [[VTL>>doc:sdmx:Glossary.Validation and transformation language.WebHome]] because a [[VTL>>doc:sdmx:Glossary.Validation and transformation language.WebHome]] [[data set>>doc:sdmx:Glossary.Data set.WebHome]] is meant to be a set of observations (data points) on a logical plane, having the same logical data structure and the same general meaning, independently of the possible physical [[representation>>doc:sdmx:Glossary.Representation.WebHome]] or storage (see [[VTL>>doc:sdmx:Glossary.Validation and transformation language.WebHome]] 2.0 User Manual page 24), therefore a [[SDMX>>doc:sdmx:Glossary.Statistical data and metadata exchange.WebHome]] [[Dataflow>>doc:sdmx:Glossary.Dataflow.WebHome]] can be seen either as a unique set of data observations (corresponding to one [[VTL>>doc:sdmx:Glossary.Validation and transformation language.WebHome]] [[data set>>doc:sdmx:Glossary.Data set.WebHome]]) or as the union of many sets of data observations (each one corresponding to a distinct [[VTL>>doc:sdmx:Glossary.Validation and transformation language.WebHome]] [[data set>>doc:sdmx:Glossary.Data set.WebHome]]).
1480
1481 As a matter of fact, in some cases it can be useful to define [[VTL>>doc:sdmx:Glossary.Validation and transformation language.WebHome]] operations involving definite parts of a [[SDMX>>doc:sdmx:Glossary.Statistical data and metadata exchange.WebHome]] [[Dataflow>>doc:sdmx:Glossary.Dataflow.WebHome]] instead than the whole.{{footnote}}A typical example of this kind is the validation, and more in general the manipulation, of individual time series belonging to the same Dataflow, identifiable through the dimension components of the Dataflow except the time Dimension. The coding of these kind of operations might be simplified by mapping distinct time series (i.e. different parts of a SDMX Dataflow) to distinct VTL data sets.{{/footnote}}
1482
1483 Therefore, in order to make the coding of [[VTL>>doc:sdmx:Glossary.Validation and transformation language.WebHome]] operations simpler when applied on parts of [[SDMX>>doc:sdmx:Glossary.Statistical data and metadata exchange.WebHome]] [[Dataflows>>doc:sdmx:Glossary.Dataflow.WebHome]], it is allowed to (% style="color:#e74c3c" %)map(%%) distinct parts of a [[SDMX>>doc:sdmx:Glossary.Statistical data and metadata exchange.WebHome]] [[Dataflow>>doc:sdmx:Glossary.Dataflow.WebHome]] to distinct [[VTL>>doc:sdmx:Glossary.Validation and transformation language.WebHome]] [[data sets>>doc:sdmx:Glossary.Data set.WebHome]] according to the following rules and conventions. This kind of mapping is possible both from [[SDMX>>doc:sdmx:Glossary.Statistical data and metadata exchange.WebHome]] to [[VTL>>doc:sdmx:Glossary.Validation and transformation language.WebHome]] and from [[VTL>>doc:sdmx:Glossary.Validation and transformation language.WebHome]] to [[SDMX>>doc:sdmx:Glossary.Statistical data and metadata exchange.WebHome]], as better explained below.{{footnote}}The kind of mapping explained here works in combination with a SDMX specific naming convention that requires pre-processing before parsing the VTL expressions. As highlighted below, the identifiers of the VTL datasets are a shortcut of some specific VTL operators applied to the SDMX Dataflows. This is not safe to use outside an SDMX context, as the naming convention may have no meaning there.{{/footnote}}
1484
1485 Given a [[SDMX>>doc:sdmx:Glossary.Statistical data and metadata exchange.WebHome]] [[Dataflow>>doc:sdmx:Glossary.Dataflow.WebHome]] and some predefined [[Dimensions>>doc:sdmx:Glossary.Dimension.WebHome]] of its DataStructure, it is allowed to (% style="color:#e74c3c" %)map(%%) the subsets of observations that have the same combination of values for such [[Dimensions>>doc:sdmx:Glossary.Dimension.WebHome]] to correspondent [[VTL>>doc:sdmx:Glossary.Validation and transformation language.WebHome]] [[datasets>>doc:sdmx:Glossary.Data set.WebHome]].
1486
1487 For example, assuming that the [[SDMX>>doc:sdmx:Glossary.Statistical data and metadata exchange.WebHome]] [[dataflow>>doc:sdmx:Glossary.Dataflow.WebHome]] DF1(1.0) has the [[Dimensions>>doc:sdmx:Glossary.Dimension.WebHome]] INDICATOR, TIME_PERIOD and COUNTRY, and that the user declares the [[Dimensions>>doc:sdmx:Glossary.Dimension.WebHome]] INDICATOR and COUNTRY as basis for the mapping (i.e. the mapping [[dimensions>>doc:sdmx:Glossary.Dimension.WebHome]]): the observations that have the same values for INDICATOR and COUNTRY would be (% style="color:#e74c3c" %)mapped(%%) to the same [[VTL>>doc:sdmx:Glossary.Validation and transformation language.WebHome]] [[dataset>>doc:sdmx:Glossary.Data set.WebHome]] (and vice-versa).
1488
1489 In practice, this kind mapping is obtained like follows:
1490
1491 * For a given [[SDMX>>doc:sdmx:Glossary.Statistical data and metadata exchange.WebHome]] [[dataflow>>doc:sdmx:Glossary.Dataflow.WebHome]], the user ([[VTL>>doc:sdmx:Glossary.Validation and transformation language.WebHome]] definer) declares the [[dimension>>doc:sdmx:Glossary.Dimension.WebHome]] [[components>>doc:sdmx:Glossary.Component.WebHome]] on which the mapping will be based, in a given order.{{footnote}}This definition is made through the ToVtlSubspace and ToVtlSpaceKey classes and/or the FromVtlSuperspace and FromVtlSpaceKey classes, depending on the direction of the mapping (“key” means “dimension”). The mapping of Dataflow subsets can be applied independently in the two directions, also according to different Dimensions. When no Dimension is declared for a given direction, it is assumed that the option of mapping different parts of a SDMX Dataflow to different VTL datasets is not used.{{/footnote}} Following the example above, imagine that the user declares the [[dimensions>>doc:sdmx:Glossary.Dimension.WebHome]] INDICATOR and COUNTRY.
1492 * The [[VTL>>doc:sdmx:Glossary.Validation and transformation language.WebHome]] [[dataset>>doc:sdmx:Glossary.Data set.WebHome]] is given a name using a special notation also called “ordered concatenation” and composed of the following parts: 
1493 ** The reference to the [[SDMX>>doc:sdmx:Glossary.Statistical data and metadata exchange.WebHome]] [[dataflow>>doc:sdmx:Glossary.Dataflow.WebHome]] (expressed according to the rules described in the previous paragraphs, i.e. URN, abbreviated URN or another alias); for example DF(1.0);
1494 ** a slash (“/”) as a separator;{{footnote}}As a consequence of this formalism, a slash in the name of the VTL dataset assumes the specific meaning of separator between the name of the Dataflow and the values of some of its Dimensions.{{/footnote}}
1495 ** The reference to a specific part of the [[SDMX>>doc:sdmx:Glossary.Statistical data and metadata exchange.WebHome]] [[dataflow>>doc:sdmx:Glossary.Dataflow.WebHome]] above, expressed as the concatenation of the values that the [[SDMX>>doc:sdmx:Glossary.Statistical data and metadata exchange.WebHome]] [[dimensions>>doc:sdmx:Glossary.Dimension.WebHome]] declared above must have, separated by dots (“.”) and written in the order in which these [[dimensions>>doc:sdmx:Glossary.Dimension.WebHome]] are defined{{footnote}}This is the order in which the dimensions are defined in the ToVtlSpaceKey class or in the FromVtlSpaceKey class, depending on the direction of the mapping.{{/footnote}}. For example POPULATION.USA would mean that such a [[VTL>>doc:sdmx:Glossary.Validation and transformation language.WebHome]] [[dataset>>doc:sdmx:Glossary.Data set.WebHome]] is (% style="color:#e74c3c" %)mapped(%%) to the [[SDMX>>doc:sdmx:Glossary.Statistical data and metadata exchange.WebHome]] observations for which the [[dimension>>doc:sdmx:Glossary.Dimension.WebHome]] //INDICATOR// is equal to POPULATION and the [[dimension>>doc:sdmx:Glossary.Dimension.WebHome]] //COUNTRY// is equal to USA.
1496
1497 In the [[VTL>>doc:sdmx:Glossary.Validation and transformation language.WebHome]] transformations, this kind of [[dataset>>doc:sdmx:Glossary.Data set.WebHome]] name must be referenced between single quotes because the slash (“/”) is not a regular character according to the [[VTL>>doc:sdmx:Glossary.Validation and transformation language.WebHome]] rules.
1498
1499 Therefore, the generic name of this kind of [[VTL>>doc:sdmx:Glossary.Validation and transformation language.WebHome]] [[datasets>>doc:sdmx:Glossary.Data set.WebHome]] would be:
1500
1501 > ‘DF(1.0)///INDICATORvalue//.//COUNTRYvalue//’
1502
1503 Where DF(1.0) is the [[Dataflow>>doc:sdmx:Glossary.Dataflow.WebHome]] and //INDICATORvalue// and //COUNTRYvalue //are placeholders for one value of the INDICATOR and // //COUNTRY dimensions.
1504
1505 Instead the specific name of one of these [[VTL>>doc:sdmx:Glossary.Validation and transformation language.WebHome]] [[datasets>>doc:sdmx:Glossary.Data set.WebHome]] would be:
1506
1507 > ‘DF(1.0)/POPULATION.USA’
1508
1509 In particular, this is the [[VTL>>doc:sdmx:Glossary.Validation and transformation language.WebHome]] [[dataset>>doc:sdmx:Glossary.Data set.WebHome]] that contains all the observations of the [[dataflow>>doc:sdmx:Glossary.Dataflow.WebHome]] DF(1.0) for which //INDICATOR// = POPULATION and //COUNTRY// = USA.
1510
1511 Let us now analyse the different meaning of this kind of mapping in the two mapping directions, i.e. from [[SDMX>>doc:sdmx:Glossary.Statistical data and metadata exchange.WebHome]] to [[VTL>>doc:sdmx:Glossary.Validation and transformation language.WebHome]] and from [[VTL>>doc:sdmx:Glossary.Validation and transformation language.WebHome]] to [[SDMX>>doc:sdmx:Glossary.Statistical data and metadata exchange.WebHome]].
1512
1513 As already said, the mapping from [[SDMX>>doc:sdmx:Glossary.Statistical data and metadata exchange.WebHome]] to [[VTL>>doc:sdmx:Glossary.Validation and transformation language.WebHome]] happens when the [[VTL>>doc:sdmx:Glossary.Validation and transformation language.WebHome]] [[datasets>>doc:sdmx:Glossary.Data set.WebHome]] are operand of [[VTL>>doc:sdmx:Glossary.Validation and transformation language.WebHome]] transformations, instead the mapping from [[VTL>>doc:sdmx:Glossary.Validation and transformation language.WebHome]] to [[SDMX>>doc:sdmx:Glossary.Statistical data and metadata exchange.WebHome]] happens when the [[VTL>>doc:sdmx:Glossary.Validation and transformation language.WebHome]] [[datasets>>doc:sdmx:Glossary.Data set.WebHome]] are result of [[VTL>>doc:sdmx:Glossary.Validation and transformation language.WebHome]] transformation{{footnote}}t should be remembered that, according to the VTL consistency rules, a given VTL dataset cannot be the result of more than one VTL transformation.{{/footnote}} and need to be treated as [[SDMX>>doc:sdmx:Glossary.Statistical data and metadata exchange.WebHome]] objects. This kind of mapping can be applied independently in the two directions and the [[Dimensions>>doc:sdmx:Glossary.Dimension.WebHome]] on which the mapping is based can be different in the two directions: these [[Dimensions>>doc:sdmx:Glossary.Dimension.WebHome]] are defined in the ToVtlSpaceKey and in the FromVtlSpaceKey classes respectively.
1514
1515 First, let us see what happens in the__ mapping direction from [[SDMX>>doc:sdmx:Glossary.Statistical data and metadata exchange.WebHome]] to [[VTL>>doc:sdmx:Glossary.Validation and transformation language.WebHome]]__, i.e. when parts of a [[SDMX>>doc:sdmx:Glossary.Statistical data and metadata exchange.WebHome]] [[dataflow>>doc:sdmx:Glossary.Dataflow.WebHome]] (e.g. DF1(1.0)) need to be (% style="color:#e74c3c" %)mapped(%%) to distinct [[VTL>>doc:sdmx:Glossary.Validation and transformation language.WebHome]] [[datasets>>doc:sdmx:Glossary.Data set.WebHome]] that are operand of some [[VTL>>doc:sdmx:Glossary.Validation and transformation language.WebHome]] transformations.
1516
1517 As already said, each [[VTL>>doc:sdmx:Glossary.Validation and transformation language.WebHome]] [[dataset>>doc:sdmx:Glossary.Data set.WebHome]] is assumed to contain all the observations of the [[SDMX>>doc:sdmx:Glossary.Statistical data and metadata exchange.WebHome]] [[dataflow>>doc:sdmx:Glossary.Dataflow.WebHome]] having INDICATOR=//INDICATORvalue //and COUNTRY=//COUNTRYvalue//. For example, the [[VTL>>doc:sdmx:Glossary.Validation and transformation language.WebHome]] [[dataset>>doc:sdmx:Glossary.Data set.WebHome]] ‘DF1(1.0)/POPULATION.USA’ would contain all the observations of DF1(1.0) having INDICATOR = POPULATION and COUNTRY = USA.
1518
1519 In order to obtain the data structure of these [[VTL>>doc:sdmx:Glossary.Validation and transformation language.WebHome]] [[datasets>>doc:sdmx:Glossary.Data set.WebHome]] from the [[SDMX>>doc:sdmx:Glossary.Statistical data and metadata exchange.WebHome]] one, it is assumed that the [[SDMX>>doc:sdmx:Glossary.Statistical data and metadata exchange.WebHome]] [[dimensions>>doc:sdmx:Glossary.Dimension.WebHome]] on which the mapping is based are dropped, i.e. not maintained in the [[VTL>>doc:sdmx:Glossary.Validation and transformation language.WebHome]] data structure; this is possible because their values are fixed for each one of the invoked [[VTL>>doc:sdmx:Glossary.Validation and transformation language.WebHome]] [[datasets>>doc:sdmx:Glossary.Data set.WebHome]] {{footnote}}This is the order in which the dimensions are defined in the ToVtlSpaceKey class or in the FromVtlSpaceKey class, depending on the direction of the mapping.{{/footnote}}. After that, the mapping method from [[SDMX>>doc:sdmx:Glossary.Statistical data and metadata exchange.WebHome]] to [[VTL>>doc:sdmx:Glossary.Validation and transformation language.WebHome]] specified for the [[dataflow>>doc:sdmx:Glossary.Dataflow.WebHome]] DF1(1.0) is applied (i.e. basic, pivot …).
1520
1521 In the example above, for all the [[datasets>>doc:sdmx:Glossary.Data set.WebHome]] of the kind ‘DF1(1.0)///INDICATORvalue//.//COUNTRYvalue//’, the [[dimensions>>doc:sdmx:Glossary.Dimension.WebHome]] INDICATOR and COUNTRY would be dropped so that the data structure of all the resulting [[VTL>>doc:sdmx:Glossary.Validation and transformation language.WebHome]] [[data sets>>doc:sdmx:Glossary.Data set.WebHome]] would have the identifier TIME_PERIOD only.
1522
1523 It should be noted that the desired [[VTL>>doc:sdmx:Glossary.Validation and transformation language.WebHome]] [[datasets>>doc:sdmx:Glossary.Data set.WebHome]] (i.e. of the kind ‘DF1(1.0)/// INDICATORvalue//.//COUNTRYvalue//’) can be obtained also by applying the [[VTL>>doc:sdmx:Glossary.Validation and transformation language.WebHome]] operator “**sub**” (subspace) to the [[dataflow>>doc:sdmx:Glossary.Dataflow.WebHome]] DF1(1.0), like in the following [[VTL>>doc:sdmx:Glossary.Validation and transformation language.WebHome]] expression:
1524
1525 > ‘DF1(1.0)/POPULATION.USA’ :=
1526 > DF1(1.0) [ sub INDICATOR=“POPULATION”, COUNTRY=“USA” ];
1527 > ‘DF1(1.0)/POPULATION.CANADA’ :=
1528 > DF1(1.0) [ sub INDICATOR=“POPULATION”, COUNTRY=“CANADA” ];
1529 > …   …   …
1530
1531 In fact the [[VTL>>doc:sdmx:Glossary.Validation and transformation language.WebHome]] operator “sub” has exactly the same behaviour. Therefore, (% style="color:#e74c3c" %)mapping(%%) different parts of a [[SDMX>>doc:sdmx:Glossary.Statistical data and metadata exchange.WebHome]] [[dataflow>>doc:sdmx:Glossary.Dataflow.WebHome]] to different [[VTL>>doc:sdmx:Glossary.Validation and transformation language.WebHome]] [[datasets>>doc:sdmx:Glossary.Data set.WebHome]] in the direction from [[SDMX>>doc:sdmx:Glossary.Statistical data and metadata exchange.WebHome]] to [[VTL>>doc:sdmx:Glossary.Validation and transformation language.WebHome]] through the ordered concatenation notation is equivalent to a proper use of the operator “**sub**” on such a [[dataflow>>doc:sdmx:Glossary.Dataflow.WebHome]].{{footnote}}In case the ordered concatenation notation is used, the VTL Transformation described above, e.g. ‘DF1(1.0)/POPULATION.USA’ := DF1(1.0) [ sub INDICATOR=“POPULATION”, COUNTRY=“USA”], is implicitly executed and, in order to test the overall compliance of the VTL program to the VTL consistency rules, it has to be considered as part of the VTL program even if it is not explicitly coded.{{/footnote}}
1532
1533 In the direction from [[SDMX>>doc:sdmx:Glossary.Statistical data and metadata exchange.WebHome]] to [[VTL>>doc:sdmx:Glossary.Validation and transformation language.WebHome]] it is allowed to omit the value of one or more [[Dimensions>>doc:sdmx:Glossary.Dimension.WebHome]] on which the (% style="color:#e74c3c" %)mapping(%%) is based, but maintaining all the separating dots (therefore it may happen to find two or more consecutive dots and dots in the beginning or in the end). The absence of value means that for the corresponding [[Dimension>>doc:sdmx:Glossary.Dimension.WebHome]] all the values are kept and the [[Dimension>>doc:sdmx:Glossary.Dimension.WebHome]] is not dropped.
1534
1535 For example, ‘DF(1.0)/POPULATION.’ (note the dot in the end of the name) is the [[VTL>>doc:sdmx:Glossary.Validation and transformation language.WebHome]] [[dataset>>doc:sdmx:Glossary.Data set.WebHome]] that contains all the observations of the [[dataflow>>doc:sdmx:Glossary.Dataflow.WebHome]] DF(1.0) for which //INDICATOR// = POPULATION and COUNTRY = any value.
1536
1537 This is equivalent to the application of the [[VTL>>doc:sdmx:Glossary.Validation and transformation language.WebHome]] “sub” operator only to the identifier //INDICATOR//:
1538
1539 > ‘DF1(1.0)/POPULATION.’ := 
1540 > DF1(1.0) [sub INDICATOR=“POPULATION” ];
1541
1542 Therefore the [[VTL>>doc:sdmx:Glossary.Validation and transformation language.WebHome]] [[dataset>>doc:sdmx:Glossary.Data set.WebHome]] ‘DF1(1.0)/POPULATION.’ would have the identifiers COUNTRY and TIME_PERIOD.
1543
1544 Heterogeneous invocations of the same [[Dataflow>>doc:sdmx:Glossary.Dataflow.WebHome]] are allowed, i.e. omitting different [[Dimensions>>doc:sdmx:Glossary.Dimension.WebHome]] in different invocations.
1545
1546 Let us now analyse the __mapping direction from [[VTL>>doc:sdmx:Glossary.Validation and transformation language.WebHome]] to [[SDMX>>doc:sdmx:Glossary.Statistical data and metadata exchange.WebHome]]__.
1547
1548 In this situation, distinct parts of a [[SDMX>>doc:sdmx:Glossary.Statistical data and metadata exchange.WebHome]] [[dataflow>>doc:sdmx:Glossary.Dataflow.WebHome]] are calculated as distinct [[VTL>>doc:sdmx:Glossary.Validation and transformation language.WebHome]] [[datasets>>doc:sdmx:Glossary.Data set.WebHome]], under the (% style="color:#e74c3c" %)constraint(%%) that they must have the same [[VTL>>doc:sdmx:Glossary.Validation and transformation language.WebHome]] data structure.
1549
1550 For example, let us assume that the [[VTL>>doc:sdmx:Glossary.Validation and transformation language.WebHome]] programmer wants to calculate the [[SDMX>>doc:sdmx:Glossary.Statistical data and metadata exchange.WebHome]] [[dataflow>>doc:sdmx:Glossary.Dataflow.WebHome]] DF2(1.0) having the [[Dimensions>>doc:sdmx:Glossary.Dimension.WebHome]] TIME_PERIOD, INDICATOR, and COUNTRY and that such a programmer finds it convenient to calculate separately the parts of DF2(1.0) that have different combinations of values for INDICATOR and COUNTRY:
1551
1552 * each part is calculated as a [[VTL>>doc:sdmx:Glossary.Validation and transformation language.WebHome]] derived [[dataset>>doc:sdmx:Glossary.Data set.WebHome]], result of a dedicated [[VTL>>doc:sdmx:Glossary.Validation and transformation language.WebHome]] transformation;{{footnote}}If the whole DF2(1.0) is calculated by means of just one VTL transformation, then the mapping between the SDMX dataflow and the corresponding VTL dataset is one-to-one and this kind of mapping (one SDMX Dataflow to many VTL datasets) does not apply.{{/footnote}}
1553 * the data structure of all these [[VTL>>doc:sdmx:Glossary.Validation and transformation language.WebHome]] [[datasets>>doc:sdmx:Glossary.Data set.WebHome]] has the TIME_PERIOD identifier and does not have the INDICATOR and COUNTRY identifiers{{footnote}}This is possible as each VTL dataset corresponds to one particular combination of values of INDICATOR and COUNTRY{{/footnote}}.
1554 * In fact the VTL operator “sub” has exactly the same behaviour. Therefore, Under these hypothesis, such derived [[VTL>>doc:sdmx:Glossary.Validation and transformation language.WebHome]] [[datasets>>doc:sdmx:Glossary.Data set.WebHome]] can be (% style="color:#e74c3c" %)mapped(%%) to DF2(1.0) by declaring the [[Dimensions>>doc:sdmx:Glossary.Dimension.WebHome]] INDICATOR and COUNTRY as mapping [[dimensions>>doc:sdmx:Glossary.Dimension.WebHome]].{{footnote}}The mapping dimensions are defined as FromVtlSpaceKeys of the FromVtlSuperSpace of the VtlDataflowMapping relevant to DF2(1.0){{/footnote}}
1555
1556 The corresponding [[VTL>>doc:sdmx:Glossary.Validation and transformation language.WebHome]] transformations, assuming that the result needs to be persistent, would be of this kind:{{footnote}}the symbol of the VTL persistent assignment is used (<-){{/footnote}}
1557
1558 ‘DF2(1.0)///INDICATORvalue//.//COUNTRYvalue//’  <-  expression
1559
1560 Some examples follow, for some specific values of INDICATOR and COUNTRY:
1561
1562 ‘DF2(1.0)/GDPPERCAPITA.USA’  <-   expression11;
1563 ‘DF2(1.0)/GDPPERCAPITA.CANADA’   <-   expression12;
1564 …   …   …
1565 ‘DF2(1.0)/POPGROWTH.USA’  <-   expression21;
1566 ‘DF2(1.0)/POPGROWTH.CANADA’  <-   expression22;
1567
1568 …   …   …
1569
1570 As said, it is assumed that these [[VTL>>doc:sdmx:Glossary.Validation and transformation language.WebHome]] derived [[datasets>>doc:sdmx:Glossary.Data set.WebHome]] have the TIME_PERIOD as the only identifier. In the mapping from [[VTL>>doc:sdmx:Glossary.Validation and transformation language.WebHome]] to SMDX, the [[Dimensions>>doc:sdmx:Glossary.Dimension.WebHome]] INDICATOR and COUNTRY are added to the [[VTL>>doc:sdmx:Glossary.Validation and transformation language.WebHome]] data structure on order to obtain the [[SDMX>>doc:sdmx:Glossary.Statistical data and metadata exchange.WebHome]] one, with the following values respectively:
1571
1572 [[image:1747859458410-183.png||height="170" width="663"]]
1573
1574 It should be noted that the application of this many-to-one mapping from [[VTL>>doc:sdmx:Glossary.Validation and transformation language.WebHome]] to [[SDMX>>doc:sdmx:Glossary.Statistical data and metadata exchange.WebHome]] is equivalent to an appropriate sequence of [[VTL>>doc:sdmx:Glossary.Validation and transformation language.WebHome]] Transformations. These use the [[VTL>>doc:sdmx:Glossary.Validation and transformation language.WebHome]] operator “calc” to add the proper [[VTL>>doc:sdmx:Glossary.Validation and transformation language.WebHome]] identifiers (in the example, INDICATOR and COUNTRY) and to assign to them the proper values and the operator “union” in order to obtain the final [[VTL>>doc:sdmx:Glossary.Validation and transformation language.WebHome]] [[dataset>>doc:sdmx:Glossary.Data set.WebHome]] (in the example DF2(1.0)), that can be (% style="color:#e74c3c" %)mapped(%%) one-to-one to the homonymous [[SDMX>>doc:sdmx:Glossary.Statistical data and metadata exchange.WebHome]] [[Dataflow>>doc:sdmx:Glossary.Dataflow.WebHome]]. Following the same example, these [[VTL>>doc:sdmx:Glossary.Validation and transformation language.WebHome]] transformations would be:
1575
1576 [[image:1747859612718-454.png||height="451" width="602"]]
1577
1578 In other words, starting from the [[datasets>>doc:sdmx:Glossary.Data set.WebHome]] explicitly calculated through [[VTL>>doc:sdmx:Glossary.Validation and transformation language.WebHome]] (in the example ‘DF2(1.0)/GDPPERCAPITA.USA’ and so on), the first step consists in calculating other (non-persistent) [[VTL>>doc:sdmx:Glossary.Validation and transformation language.WebHome]] [[datasets>>doc:sdmx:Glossary.Data set.WebHome]] (in the example DF2bis_GDPPERCAPITA_USA and so on) by adding the identifiers INDICATOR and COUNTRY with the desired values (//INDICATORvalue// and //COUNTRYvalue)//. Finally, all these non-persistent [[data sets>>doc:sdmx:Glossary.Data set.WebHome]] are united and give the final result DF2(1.0){{footnote}}The result is persistent in this example but it can be also non persistent if needed.{{/footnote}}, which can be (% style="color:#e74c3c" %)mapped(%%) one-to-one to the homonymous [[SDMX>>doc:sdmx:Glossary.Statistical data and metadata exchange.WebHome]] [[dataflow>>doc:sdmx:Glossary.Dataflow.WebHome]] having the [[dimension>>doc:sdmx:Glossary.Dimension.WebHome]] [[components>>doc:sdmx:Glossary.Component.WebHome]] TIME_PERIOD, INDICATOR and COUNTRY.
1579
1580 Therefore, (% style="color:#e74c3c" %)mapping(%%) different [[VTL>>doc:sdmx:Glossary.Validation and transformation language.WebHome]] [[datasets>>doc:sdmx:Glossary.Data set.WebHome]] having the same data structure to different parts of a [[SDMX>>doc:sdmx:Glossary.Statistical data and metadata exchange.WebHome]] [[dataflow>>doc:sdmx:Glossary.Dataflow.WebHome]], i.e. in the direction from [[VTL>>doc:sdmx:Glossary.Validation and transformation language.WebHome]] to [[SDMX>>doc:sdmx:Glossary.Statistical data and metadata exchange.WebHome]], through the ordered concatenation notation is equivalent to a proper use of the operators “calc” and “union” on such [[datasets>>doc:sdmx:Glossary.Data set.WebHome]]. [[(% class="wikiinternallink wikiinternallink wikiinternallink wikiinternallink wikiinternallink wikiinternallink wikiinternallink wikiinternallink wikiinternallink wikiinternallink wikiinternallink wikiinternallink wikiinternallink wikiinternallink wikiinternallink wikiinternallink wikiinternallink wikiinternallink wikiinternallink wikiinternallink wikiinternallink wikiinternallink wikiinternallink wikiinternallink wikiinternallink wikiinternallink wikiinternallink wikiinternallink wikiinternallink wikiinternallink wikiinternallink wikiinternallink wikiinternallink wikiinternallink wikiinternallink wikiinternallink wikiinternallink wikiinternallink wikiinternallink wikiinternallink wikiinternallink wikiinternallink wikiinternallink wikiinternallink wikiinternallink wikiinternallink wikiinternallink wikiinternallink wikiinternallink wikiinternallink wikiinternallink wikiinternallink wikiinternallink wikiinternallink wikiinternallink wikiinternallink wikiinternallink wikiinternallink wikiinternallink wikiinternallink wikiinternallink wikiinternallink wikiinternallink wikiinternallink wikiinternallink wikiinternallink wikiinternallink wikiinternallink wikiinternallink wikiinternallink wikiinternallink wikiinternallink wikiinternallink wikiinternallink wikiinternallink wikiinternallink wikiinternallink wikiinternallink wikiinternallink wikiinternallink wikiinternallink wikiinternallink wikiinternallink wikiinternallink wikiinternallink wikiinternallink wikiinternallink wikiinternallink wikiinternallink wikiinternallink wikiinternallink wikiinternallink wikiinternallink wikiinternallink wikiinternallink" %)^^~[39~]^^>>path:#_ftn39]](%%)[[(% class="wikiinternallink wikiinternallink wikiinternallink wikiinternallink wikiinternallink wikiinternallink wikiinternallink wikiinternallink wikiinternallink wikiinternallink wikiinternallink wikiinternallink wikiinternallink wikiinternallink wikiinternallink wikiinternallink wikiinternallink wikiinternallink wikiinternallink wikiinternallink wikiinternallink wikiinternallink wikiinternallink wikiinternallink wikiinternallink wikiinternallink wikiinternallink wikiinternallink wikiinternallink wikiinternallink wikiinternallink wikiinternallink wikiinternallink wikiinternallink wikiinternallink wikiinternallink wikiinternallink wikiinternallink wikiinternallink wikiinternallink wikiinternallink wikiinternallink wikiinternallink wikiinternallink wikiinternallink wikiinternallink wikiinternallink wikiinternallink wikiinternallink wikiinternallink wikiinternallink wikiinternallink wikiinternallink wikiinternallink wikiinternallink wikiinternallink wikiinternallink wikiinternallink wikiinternallink wikiinternallink wikiinternallink wikiinternallink wikiinternallink wikiinternallink wikiinternallink wikiinternallink wikiinternallink wikiinternallink wikiinternallink wikiinternallink wikiinternallink wikiinternallink wikiinternallink wikiinternallink wikiinternallink wikiinternallink wikiinternallink wikiinternallink wikiinternallink wikiinternallink wikiinternallink wikiinternallink wikiinternallink wikiinternallink wikiinternallink wikiinternallink wikiinternallink wikiinternallink wikiinternallink wikiinternallink wikiinternallink wikiinternallink wikiinternallink wikiinternallink wikiinternallink" %)^^~[40~]^^>>path:#_ftn40]]
1581
1582 It is worth noting that in the direction from [[VTL>>doc:sdmx:Glossary.Validation and transformation language.WebHome]] to [[SDMX>>doc:sdmx:Glossary.Statistical data and metadata exchange.WebHome]] it is mandatory to specify the value for every [[Dimension>>doc:sdmx:Glossary.Dimension.WebHome]] on which the (% style="color:#e74c3c" %)mapping(%%) is based (in other word, in the name of the calculated [[VTL>>doc:sdmx:Glossary.Validation and transformation language.WebHome]] [[dataset>>doc:sdmx:Glossary.Data set.WebHome]] is not possible to omit the value of some of the Dimensions).
1583
1584 === 10.3.7 Mapping variables and value domains between VTL and SDMX ===
1585
1586 With reference to the [[VTL>>doc:sdmx:Glossary.Validation and transformation language.WebHome]] “model for Variables and Value domains”, the following additional mappings have to be considered:
1587
1588 (% style="width:890.835px" %)
1589 |(% style="width:314px" %)VTL|(% style="width:574px" %)SDMX
1590 |(% style="width:314px" %)**[[Data Set>>doc:sdmx:Glossary.Data set.WebHome]] [[Component>>doc:sdmx:Glossary.Component.WebHome]]**|(% style="width:574px" %)Although this abstraction exists in [[SDMX>>doc:sdmx:Glossary.Statistical data and metadata exchange.WebHome]], it does not have an explicit definition and correspond to a [[Component>>doc:sdmx:Glossary.Component.WebHome]] (either a [[Dimension>>doc:sdmx:Glossary.Dimension.WebHome]] or a PrimaryMeasure or a DataAttribute) belonging to one specific [[Dataflow>>doc:sdmx:Glossary.Dataflow.WebHome]]^^42^^
1591 |(% style="width:314px" %)**Represented Variable**|(% style="width:574px" %)(% style="color:#e74c3c" %)**Concept**(%%) with a definite [[Representation>>doc:sdmx:Glossary.Representation.WebHome]]
1592 |(% style="width:314px" %)**Value Domain**|(% style="width:574px" %)**[[Representation>>doc:sdmx:Glossary.Representation.WebHome]]** (see the Structure Pattern in the Base Package)
1593 |(% style="width:314px" %)**Enumerated Value Domain / [[Code List>>doc:sdmx:Glossary.Code list.WebHome]]**|(% style="width:574px" %)(((
1594 **Codelist** (for enumerated [[Dimension>>doc:sdmx:Glossary.Dimension.WebHome]], PrimaryMeasure, DataAttribute) or **ConceptScheme **(for MeasureDimension)
1595 )))
1596 |(% style="width:314px" %)**[[Code>>doc:sdmx:Glossary.Code.WebHome]]**|(% style="width:574px" %)**[[Code>>doc:sdmx:Glossary.Code.WebHome]]** (for enumerated [[Dimension>>doc:sdmx:Glossary.Dimension.WebHome]], PrimaryMeasure, DataAttribute) or (% style="color:#e74c3c" %)**Concept**(%%) (for MeasureDimension)
1597 |(% style="width:314px" %)**Described Value Domain**|(% style="width:574px" %)(((
1598 non-enumerated** [[Representation>>doc:sdmx:Glossary.Representation.WebHome]] **(having [[Facets>>doc:sdmx:Glossary.Facet.WebHome]] / ExtendedFacets, see the Structure Pattern in the Base Package)
1599 )))
1600 |(% style="width:314px" %)**Value**|(% style="width:574px" %)(((
1601 Although this abstraction exists in [[SDMX>>doc:sdmx:Glossary.Statistical data and metadata exchange.WebHome]], it does not have an explicit definition and correspond to a **[[Code>>doc:sdmx:Glossary.Code.WebHome]]** of a Codelist (for enumerated [[Representations>>doc:sdmx:Glossary.Representation.WebHome]]) or to a valid **value **(for non-enumerated** **[[Representations>>doc:sdmx:Glossary.Representation.WebHome]]) or to a (% style="color:#e74c3c" %)**Concept**(%%)** **(for MeasureDimension)
1602 )))
1603 |(% style="width:314px" %)**Value Domain Subset / Set**|(% style="width:574px" %)This abstraction does not exist in [[SDMX>>doc:sdmx:Glossary.Statistical data and metadata exchange.WebHome]]
1604 |(% style="width:314px" %)**Enumerated Value Domain Subset / Enumerated Set**|(% style="width:574px" %)This abstraction does not exist in [[SDMX>>doc:sdmx:Glossary.Statistical data and metadata exchange.WebHome]]
1605 |(% style="width:314px" %)**Described Value Domain Subset / Described Set**|(% style="width:574px" %)This abstraction does not exist in [[SDMX>>doc:sdmx:Glossary.Statistical data and metadata exchange.WebHome]]
1606 |(% style="width:314px" %)**Set list**|(% style="width:574px" %)This abstraction does not exist in [[SDMX>>doc:sdmx:Glossary.Statistical data and metadata exchange.WebHome]]
1607
1608 The main difference between [[VTL>>doc:sdmx:Glossary.Validation and transformation language.WebHome]] and [[SDMX>>doc:sdmx:Glossary.Statistical data and metadata exchange.WebHome]] relies on the fact that the [[VTL>>doc:sdmx:Glossary.Validation and transformation language.WebHome]] [[artefacts>>doc:sdmx:Glossary.Artefact.WebHome]] for defining subsets of Value Domains do not exist in [[SDMX>>doc:sdmx:Glossary.Statistical data and metadata exchange.WebHome]], therefore the [[VTL>>doc:sdmx:Glossary.Validation and transformation language.WebHome]] features for referring to predefined subsets are not available in [[SDMX>>doc:sdmx:Glossary.Statistical data and metadata exchange.WebHome]]. These [[artefacts>>doc:sdmx:Glossary.Artefact.WebHome]] are the Value Domain Subset (or Set), either enumerated or described, the Set List (list of values belonging to enumerated subsets) and the [[Data Set>>doc:sdmx:Glossary.Data set.WebHome]] [[Component>>doc:sdmx:Glossary.Component.WebHome]] (aimed at defining the set of values that the [[Component>>doc:sdmx:Glossary.Component.WebHome]] of a [[Data Set>>doc:sdmx:Glossary.Data set.WebHome]] can take, possibly a subset of the [[codes>>doc:sdmx:Glossary.Code.WebHome]] of Value Domain).
1609
1610 Another difference consists in the fact that all Value Domains are considered as identifiable objects in [[VTL>>doc:sdmx:Glossary.Validation and transformation language.WebHome]] either if enumerated or not, while in [[SDMX>>doc:sdmx:Glossary.Statistical data and metadata exchange.WebHome]] the Codelist (corresponding to a [[VTL>>doc:sdmx:Glossary.Validation and transformation language.WebHome]] enumerated Value Domain) is identifiable, while the [[SDMX>>doc:sdmx:Glossary.Statistical data and metadata exchange.WebHome]] non-enumerated [[Representation>>doc:sdmx:Glossary.Representation.WebHome]] (corresponding to a [[VTL>>doc:sdmx:Glossary.Validation and transformation language.WebHome]] non-enumerated Value Domain) is not identifiable. As a consequence, the definition of the [[VTL>>doc:sdmx:Glossary.Validation and transformation language.WebHome]] rulesets, which in [[VTL>>doc:sdmx:Glossary.Validation and transformation language.WebHome]] can refer either to enumerated or non-enumerated value domains, in [[SDMX>>doc:sdmx:Glossary.Statistical data and metadata exchange.WebHome]] can refer only to enumerated Value Domains (i.e. to [[SDMX>>doc:sdmx:Glossary.Statistical data and metadata exchange.WebHome]] Codelists).
1611
1612 As for the (% style="color:#e74c3c" %)mapping(%%) between [[VTL>>doc:sdmx:Glossary.Validation and transformation language.WebHome]] variables and [[SDMX>>doc:sdmx:Glossary.Statistical data and metadata exchange.WebHome]] (% style="color:#e74c3c" %)Concepts(%%), it should be noted that these [[artefacts>>doc:sdmx:Glossary.Artefact.WebHome]] do not coincide perfectly. In fact, the [[VTL>>doc:sdmx:Glossary.Validation and transformation language.WebHome]] variables are represented variables, defined always on the same Value Domain (“[[Representation>>doc:sdmx:Glossary.Representation.WebHome]]” in [[SDMX>>doc:sdmx:Glossary.Statistical data and metadata exchange.WebHome]]) independently of the [[data set>>doc:sdmx:Glossary.Data set.WebHome]] / data structure in which they appear{{footnote}}By using represented variables, VTL can assume that data structures having the same variables as identifiers can be composed one another because the correspondent values can match.{{/footnote}}, while the [[SDMX>>doc:sdmx:Glossary.Statistical data and metadata exchange.WebHome]] (% style="color:#e74c3c" %)Concepts(%%) can have different [[Representations>>doc:sdmx:Glossary.Representation.WebHome]] in different DataStructures.{{footnote}}A Concept becomes a Component in a DataStructureDefinition, and Components can have different LocalRepresentations in different DataStructureDefinitions, also overriding the (possible) base representation of the Concept.{{/footnote}} This means that one [[SDMX>>doc:sdmx:Glossary.Statistical data and metadata exchange.WebHome]] (% style="color:#e74c3c" %)Concept(%%) can correspond to many [[VTL>>doc:sdmx:Glossary.Validation and transformation language.WebHome]] Variables, one for each [[representation>>doc:sdmx:Glossary.Representation.WebHome]] the (% style="color:#e74c3c" %)Concept(%%) has.
1613
1614 Therefore, it is important to be aware that some [[VTL>>doc:sdmx:Glossary.Validation and transformation language.WebHome]] operations (for example the binary operations at [[data set>>doc:sdmx:Glossary.Data set.WebHome]] (% style="color:#e74c3c" %)level(%%)) are consistent only if the [[components>>doc:sdmx:Glossary.Component.WebHome]] having the same names in the operated [[VTL>>doc:sdmx:Glossary.Validation and transformation language.WebHome]] [[data sets>>doc:sdmx:Glossary.Data set.WebHome]] have also the same [[representation>>doc:sdmx:Glossary.Representation.WebHome]] (i.e. the same Value Domain as for [[VTL>>doc:sdmx:Glossary.Validation and transformation language.WebHome]]). For example, it is possible to obtain correct results from the [[VTL>>doc:sdmx:Glossary.Validation and transformation language.WebHome]] expression
1615
1616 DS_c := DS_a + DS_b (where DS_a, DS_b, DS_c are VTL Data Sets)
1617
1618 if the matching [[components>>doc:sdmx:Glossary.Component.WebHome]] in DS_a and DS_b (e.g. ref_date, geo_area, sector …) refer to the same general [[representation>>doc:sdmx:Glossary.Representation.WebHome]]. In simpler words, DS_a and DS_b must use the same values/[[codes>>doc:sdmx:Glossary.Code.WebHome]] (for ref_date, geo_area, sector … ), otherwise the relevant values would not match and the result of the operation would be wrong.
1619
1620 As mentioned, the property above is not enforced by construction in [[SDMX>>doc:sdmx:Glossary.Statistical data and metadata exchange.WebHome]], and different [[representations>>doc:sdmx:Glossary.Representation.WebHome]] of the same (% style="color:#e74c3c" %)Concept(%%) can be not compatible one another (for example, it may happen that geo_area is represented by ISO-alpha-3 [[codes>>doc:sdmx:Glossary.Code.WebHome]] in DS_a and by ISO alpha-2 [[codes>>doc:sdmx:Glossary.Code.WebHome]] in DS_b). Therefore, it will be up to the definer of [[VTL>>doc:sdmx:Glossary.Validation and transformation language.WebHome]] transformations to ensure that the [[VTL>>doc:sdmx:Glossary.Validation and transformation language.WebHome]] expressions are consistent with the actual [[representations>>doc:sdmx:Glossary.Representation.WebHome]] of the correspondent [[SDMX>>doc:sdmx:Glossary.Statistical data and metadata exchange.WebHome]] (% style="color:#e74c3c" %)Concepts(%%).
1621
1622 It remains up to the [[SDMX>>doc:sdmx:Glossary.Statistical data and metadata exchange.WebHome]]-[[VTL>>doc:sdmx:Glossary.Validation and transformation language.WebHome]] definer also the assurance of the consistency between a [[VTL>>doc:sdmx:Glossary.Validation and transformation language.WebHome]] Ruleset defined on Variables and the [[SDMX>>doc:sdmx:Glossary.Statistical data and metadata exchange.WebHome]] [[Components>>doc:sdmx:Glossary.Component.WebHome]] on which the Ruleset is applied. In fact, a [[VTL>>doc:sdmx:Glossary.Validation and transformation language.WebHome]] Ruleset is expressed by means of the values of the Variables (i.e. [[SDMX>>doc:sdmx:Glossary.Statistical data and metadata exchange.WebHome]] (% style="color:#e74c3c" %)Concepts(%%)), i.e. assuming definite [[representations>>doc:sdmx:Glossary.Representation.WebHome]] for them (e.g. ISO-alpha-3 for country). If the Ruleset is applied to [[SDMX>>doc:sdmx:Glossary.Statistical data and metadata exchange.WebHome]] [[Components>>doc:sdmx:Glossary.Component.WebHome]] that have the same name of the (% style="color:#e74c3c" %)Concept(%%) they refer to but different [[representations>>doc:sdmx:Glossary.Representation.WebHome]] (e.g. ISO-alpha-2 for country), the Ruleset cannot work properly.
1623
1624 == 10.4 Mapping between SDMX and VTL Data Types ==
1625
1626 === 10.4.1 VTL Data types ===
1627
1628 According to the [[VTL>>doc:sdmx:Glossary.Validation and transformation language.WebHome]] User Guide the possible operations in [[VTL>>doc:sdmx:Glossary.Validation and transformation language.WebHome]] depend on the data types of the [[artefacts>>doc:sdmx:Glossary.Artefact.WebHome]]. For example, numbers can be multiplied but text strings cannot. In the [[VTL>>doc:sdmx:Glossary.Validation and transformation language.WebHome]] Transformations, the compliance between the operators and the data types of their operands is statically checked, i.e., violations result in compiletime errors.
1629
1630 The [[VTL>>doc:sdmx:Glossary.Validation and transformation language.WebHome]] data types are sub-divided in scalar types (like integers, strings, etc.), which are the types of the scalar values, and compound types (like [[data sets>>doc:sdmx:Glossary.Data set.WebHome]], [[components>>doc:sdmx:Glossary.Component.WebHome]], rulesets, etc.), which are the types of the compound structures. See below the diagram of the [[VTL>>doc:sdmx:Glossary.Validation and transformation language.WebHome]] data types, taken from the [[VTL>>doc:sdmx:Glossary.Validation and transformation language.WebHome]] User Manual:
1631
1632 [[image:1747836776716-178.png]]
1633
1634 **Figure 12 – VTL Data Types**
1635
1636 The [[VTL>>doc:sdmx:Glossary.Validation and transformation language.WebHome]] scalar types are in turn subdivided in basic scalar types, which are elementary (not defined in term of other data types) and Value Domain and Set scalar types, which are defined in terms of the basic scalar types.
1637
1638 The [[VTL>>doc:sdmx:Glossary.Validation and transformation language.WebHome]] basic scalar types are listed below and follow a hierarchical structure in terms of supersets/subsets (e.g. “scalar” is the superset of all the basic scalar types):
1639
1640 [[image:1747859722732-549.png||height="283" width="224"]]
1641
1642 **Figure 13 – VTL Basic Scalar Types**
1643
1644 === 10.4.2 VTL basic scalar types and SDMX data types ===
1645
1646 The [[VTL>>doc:sdmx:Glossary.Validation and transformation language.WebHome]] assumes that a basic scalar type has a unique internal [[representation>>doc:sdmx:Glossary.Representation.WebHome]] and can have more external [[representations>>doc:sdmx:Glossary.Representation.WebHome]].
1647
1648 The internal [[representation>>doc:sdmx:Glossary.Representation.WebHome]] is the format used within a [[VTL>>doc:sdmx:Glossary.Validation and transformation language.WebHome]] system to represent (and process) all the scalar values of a certain type. In principle, this format is hidden and not necessarily known by users. The external [[representations>>doc:sdmx:Glossary.Representation.WebHome]] are instead the external formats of the values of a certain basic scalar type, i.e. the formats known by the users. For example, the internal [[representation>>doc:sdmx:Glossary.Representation.WebHome]] of the dates can be an integer counting the days since a predefined date (e.g. from 01/01/4713 BC up to 31/12/5874897 AD like in Postgres) while two possible external [[representations>>doc:sdmx:Glossary.Representation.WebHome]] are the formats YYYY-MM-GG and MM-GG-YYYY (e.g. respectively 2010-12-31 and 1231-2010).
1649
1650 The internal [[representation>>doc:sdmx:Glossary.Representation.WebHome]] is the reference format that allows [[VTL>>doc:sdmx:Glossary.Validation and transformation language.WebHome]] to operate on more values of the same type (for example on more dates) even if such values have different external formats: these values are all converted to the unique internal [[representation>>doc:sdmx:Glossary.Representation.WebHome]] so that they can be composed together (e.g. to find the more recent date, to find the time span between these dates and so on).
1651
1652 The [[VTL>>doc:sdmx:Glossary.Validation and transformation language.WebHome]] assumes that a unique internal [[representation>>doc:sdmx:Glossary.Representation.WebHome]] exists for each basic scalar type but does not prescribe any particular format for it, leaving the [[VTL>>doc:sdmx:Glossary.Validation and transformation language.WebHome]] systems free to using they preferred or already existing internal format. By consequence, in [[VTL>>doc:sdmx:Glossary.Validation and transformation language.WebHome]] the basic scalar types are abstractions not associated to a specific format.
1653
1654 [[SDMX>>doc:sdmx:Glossary.Statistical data and metadata exchange.WebHome]] data types are conceived instead to support the data exchange, therefore they do have a format, which is known by the users and correspond, in [[VTL>>doc:sdmx:Glossary.Validation and transformation language.WebHome]] terms, to external [[representations>>doc:sdmx:Glossary.Representation.WebHome]]. Therefore, for each [[VTL>>doc:sdmx:Glossary.Validation and transformation language.WebHome]] basic scalar type there can be more [[SDMX>>doc:sdmx:Glossary.Statistical data and metadata exchange.WebHome]] data types (the latter are explained in the section “General Notes for Implementers” of this document and are actually much more numerous than the former).
1655
1656 The following paragraphs describe the mapping between the [[SDMX>>doc:sdmx:Glossary.Statistical data and metadata exchange.WebHome]] data types and the [[VTL>>doc:sdmx:Glossary.Validation and transformation language.WebHome]] basic scalar types. This mapping shall be presented in the two directions of possible conversion, i.e. from [[SDMX>>doc:sdmx:Glossary.Statistical data and metadata exchange.WebHome]] to [[VTL>>doc:sdmx:Glossary.Validation and transformation language.WebHome]] and vice-versa.
1657
1658 The conversion from [[SDMX>>doc:sdmx:Glossary.Statistical data and metadata exchange.WebHome]] to [[VTL>>doc:sdmx:Glossary.Validation and transformation language.WebHome]] happens when an [[SDMX>>doc:sdmx:Glossary.Statistical data and metadata exchange.WebHome]] [[artefact>>doc:sdmx:Glossary.Artefact.WebHome]] acts as inputs of a [[VTL>>doc:sdmx:Glossary.Validation and transformation language.WebHome]] transformation. As already said, in fact, at compile time the [[VTL>>doc:sdmx:Glossary.Validation and transformation language.WebHome]] needs to know the [[VTL>>doc:sdmx:Glossary.Validation and transformation language.WebHome]] type of the operands in order to check their compliance with the [[VTL>>doc:sdmx:Glossary.Validation and transformation language.WebHome]] operators and at runtime it must convert the values from their external ([[SDMX>>doc:sdmx:Glossary.Statistical data and metadata exchange.WebHome]]) [[representations>>doc:sdmx:Glossary.Representation.WebHome]] to the corresponding internal ([[VTL>>doc:sdmx:Glossary.Validation and transformation language.WebHome]]) ones.
1659
1660 The opposite conversion, i.e. from [[VTL>>doc:sdmx:Glossary.Validation and transformation language.WebHome]] to [[SDMX>>doc:sdmx:Glossary.Statistical data and metadata exchange.WebHome]], happens when a [[VTL>>doc:sdmx:Glossary.Validation and transformation language.WebHome]] result, i.e. a [[VTL>>doc:sdmx:Glossary.Validation and transformation language.WebHome]] [[data set>>doc:sdmx:Glossary.Data set.WebHome]] output of a transformation, must become a [[SDMX>>doc:sdmx:Glossary.Statistical data and metadata exchange.WebHome]] [[artefact>>doc:sdmx:Glossary.Artefact.WebHome]] (or part of it). The values of the [[VTL>>doc:sdmx:Glossary.Validation and transformation language.WebHome]] result must be converted into the desired ([[SDMX>>doc:sdmx:Glossary.Statistical data and metadata exchange.WebHome]]) external [[representations>>doc:sdmx:Glossary.Representation.WebHome]] (data types) of the [[SDMX>>doc:sdmx:Glossary.Statistical data and metadata exchange.WebHome]] [[artefact>>doc:sdmx:Glossary.Artefact.WebHome]].
1661
1662 === 10.4.3 Mapping SDMX data types to VTL basic scalar types ===
1663
1664 The following table describes the default mapping for converting from the [[SDMX>>doc:sdmx:Glossary.Statistical data and metadata exchange.WebHome]] data types to the [[VTL>>doc:sdmx:Glossary.Validation and transformation language.WebHome]] basic scalar types.
1665
1666 (% style="width:653.835px" %)
1667 |(% style="width:366px" %)**SDMX data type (BasicComponentDataType)**|(% style="width:284px" %)**Default [[VTL>>doc:sdmx:Glossary.Validation and transformation language.WebHome]] basic scalar type**
1668 |(% style="width:366px" %)(((
1669 **String**
1670 (string allowing any character)
1671 )))|(% style="width:284px" %)**string**
1672 |(% style="width:366px" %)(((
1673 **Alpha**
1674 (string which only allows A-z)
1675 )))|(% style="width:284px" %)**string**
1676 |(% style="width:366px" %)(((
1677 **AlphaNumeric**
1678 (string which only allows A-z and 0-9)
1679 )))|(% style="width:284px" %)**string**
1680 |(% style="width:366px" %)(((
1681 **Numeric**
1682 (string which only allows 0-9, but is not numeric so that is can having leading zeros)
1683 )))|(% style="width:284px" %)**string**
1684 |(% style="width:366px" %)(((
1685 **BigInteger**
1686 (corresponds to XML Schema xs:integer datatype; infinite set of integer values)
1687 )))|(% style="width:284px" %)**integer**
1688 |(% style="width:366px" %)(((
1689 **Integer**
1690 (corresponds to XML Schema xs:int datatype; between -2147483648 and +2147483647 (inclusive))
1691 )))|(% style="width:284px" %)**integer**
1692 |(% style="width:366px" %)(((
1693 **Long**
1694 (corresponds to XML Schema xs:long datatype; between -9223372036854775808 and +9223372036854775807 (inclusive))
1695 )))|(% style="width:284px" %)**integer**
1696 |(% style="width:366px" %)(((
1697 **Short**
1698 (corresponds to XML Schema xs:short datatype; between -32768 and -32767 (inclusive))
1699 )))|(% style="width:284px" %)**integer**
1700 |(% style="width:366px" %)(((
1701 **[[Decimal>>doc:sdmx:Glossary.Decimals.WebHome]]**
1702 (corresponds to XML Schema xs:decimal datatype; subset of real numbers that can be represented as decimals)
1703 )))|(% style="width:284px" %)**number**
1704 |(% style="width:366px" %)(((
1705 **Float**
1706 (corresponds to XML Schema xs:float datatype; patterned after the IEEE single-precision 32-bit floating point type)
1707 )))|(% style="width:284px" %)**number**
1708 |(% style="width:366px" %)(((
1709 **Double**
1710 (corresponds to XML Schema xs:double datatype; patterned after the IEEE double-precision 64-bit floating point type)
1711 )))|(% style="width:284px" %)**number**
1712 |(% style="width:366px" %)(((
1713 **Boolean**
1714 (corresponds to the XML Schema xs:boolean datatype; support the mathematical (% style="color:#e74c3c" %)concept(%%) of binary-valued logic: {true, false})
1715 )))|(% style="width:284px" %)**boolean**
1716 |(% style="width:366px" %)(((
1717 **URI**
1718 (corresponds to the XML Schema xs:anyURI; absolute or relative Uniform Resource Identifier Reference)
1719 )))|(% style="width:284px" %)**string**
1720 |(% style="width:366px" %)(((
1721 **Count**
1722 (an integer following a sequential pattern, increasing by 1 for each occurrence)
1723 )))|(% style="width:284px" %)**integer**
1724 |(% style="width:366px" %)(((
1725 **InclusiveValueRange**
1726 ([[decimal>>doc:sdmx:Glossary.Decimals.WebHome]] number within a closed interval, whose bounds are specified in the [[SDMX>>doc:sdmx:Glossary.Statistical data and metadata exchange.WebHome]] [[representation>>doc:sdmx:Glossary.Representation.WebHome]] by the [[facets>>doc:sdmx:Glossary.Facet.WebHome]] minValue and maxValue)
1727 )))|(% style="width:284px" %)**number**
1728 |(% style="width:366px" %)(((
1729 **ExclusiveValueRange**
1730 ([[decimal>>doc:sdmx:Glossary.Decimals.WebHome]] number within an open interval, whose bounds are specified in the [[SDMX>>doc:sdmx:Glossary.Statistical data and metadata exchange.WebHome]] [[representation>>doc:sdmx:Glossary.Representation.WebHome]] by the [[facets>>doc:sdmx:Glossary.Facet.WebHome]] minValue and maxValue)
1731 )))|(% style="width:284px" %)**number**
1732 |(% style="width:366px" %)(((
1733 **Incremental **
1734 ([[decimal>>doc:sdmx:Glossary.Decimals.WebHome]] number the increased by a specific interval (defined by the interval [[facet>>doc:sdmx:Glossary.Facet.WebHome]]), which is typically enforced outside of the XML validation)
1735 )))|(% style="width:284px" %)**number**
1736 |(% style="width:366px" %)(((
1737 **ObservationalTimePeriod**
1738 (superset of StandardTimePeriod and TimeRange)
1739 )))|(% style="width:284px" %)**time**
1740 |(% style="width:366px" %)(((
1741 **StandardTimePeriod**
1742 (superset of BasicTimePeriod and ReportingTimePeriod)
1743 )))|(% style="width:284px" %)**time**
1744 |(% style="width:366px" %)(((
1745 **BasicTimePeriod**
1746 (superset of GregorianTimePeriod and DateTime)
1747 )))|(% style="width:284px" %)**date**
1748 |(% style="width:366px" %)(((
1749 **GregorianTimePeriod**
1750 (superset of GregorianYear, GregorianYearMonth, and GregorianDay)
1751 )))|(% style="width:284px" %)**date**
1752 |(% style="width:366px" %)**GregorianYear **(YYYY)|(% style="width:284px" %)**date**
1753 |(% style="width:366px" %)**GregorianYearMonth** / **GregorianMonth** (YYYY-MM)|(% style="width:284px" %)**date**
1754 |(% style="width:366px" %)**GregorianDay **(YYYY-MM-DD)|(% style="width:284px" %)**date**
1755 |(% style="width:366px" %)(((
1756 **ReportingTimePeriod **
1757 (superset of RepostingYear, ReportingSemester, ReportingTrimester, ReportingQuarter, ReportingMonth, ReportingWeek, ReportingDay)
1758 )))|(% style="width:284px" %)**time_period**
1759 |(% style="width:366px" %)(((
1760 **ReportingYear**
1761 (YYYY-A1 – 1 year period)
1762 )))|(% style="width:284px" %)**time_period**
1763 |(% style="width:366px" %)(((
1764 **ReportingSemester**
1765 (YYYY-Ss – 6 month period)
1766 )))|(% style="width:284px" %)**time_period**
1767 |(% style="width:366px" %)(((
1768 **ReportingTrimester**
1769 (YYYY-Tt – 4 month period)
1770 )))|(% style="width:284px" %)**time_period**
1771 |(% style="width:366px" %)(((
1772 **ReportingQuarter**
1773 (YYYY-Qq – 3 month period)
1774 )))|(% style="width:284px" %)**time_period**
1775 |(% style="width:366px" %)(((
1776 **ReportingMonth**
1777 (YYYY-Mmm – 1 month period)
1778 )))|(% style="width:284px" %)**time_period**
1779 |(% style="width:366px" %)(((
1780 **ReportingWeek**
1781 (YYYY-Www – 7 day period; following ISO 8601 definition of a week in a year)
1782 )))|(% style="width:284px" %)**time_period**
1783 |(% style="width:366px" %)(((
1784 **ReportingDay**
1785 (YYYY-Dddd – 1 day period)
1786 )))|(% style="width:284px" %)**time_period**
1787 |(% style="width:366px" %)(((
1788 **DateTime**
1789 (YYYY-MM-DDThh:mm:ss)
1790 )))|(% style="width:284px" %)**date**
1791 |(% style="width:366px" %)(((
1792 **TimeRange**
1793
1794 (YYYY-MM-DD(Thh:mm:ss)?/)
1795 )))|(% style="width:284px" %)**time**
1796 |(% style="width:366px" %)(((
1797 **Month**
1798 (MM; speicifies a month independent of a year; e.g. February is black history month in the United States)
1799 )))|(% style="width:284px" %)**string**
1800 |(% style="width:366px" %)(((
1801 **MonthDay**
1802 (MM-DD; specifies a day within a month independent of a year; e.g. Christmas is December 25^^th^^; used to specify reporting year start day)
1803 )))|(% style="width:284px" %)**string**
1804 |(% style="width:366px" %)(((
1805 **Day**
1806 (-DD; specifies a day independent of a month or year; e.g. the 15^^th^^ is payday)
1807 )))|(% style="width:284px" %)**string**
1808 |(% style="width:366px" %)(((
1809 **Time**
1810 (hh:mm:ss; time independent of a date; e.g. coffee break is at 10:00 AM)
1811 )))|(% style="width:284px" %)**string**
1812 |(% style="width:366px" %)(((
1813 **Duration**
1814 (corresponds to XML Schema xs:duration datatype)
1815 )))|(% style="width:284px" %)**duration**
1816 |(% style="width:366px" %)XHTML|(% style="width:284px" %)Metadata type – not applicable
1817 |(% style="width:366px" %)KeyValues|(% style="width:284px" %)Metadata type – not applicable
1818 |(% style="width:366px" %)IdentifiableReference|(% style="width:284px" %)Metadata type – not applicable
1819 |(% style="width:366px" %)DataSetReference|(% style="width:284px" %)Metadata type – not applicable
1820 |(% style="width:366px" %)AttachmentConstraintReference|(% style="width:284px" %)Metadata type – not applicable
1821
1822 **Figure 14 – Mappings from SDMX data types to VTL Basic Scalar Types**
1823
1824 When [[VTL>>doc:sdmx:Glossary.Validation and transformation language.WebHome]] takes in input [[SDMX>>doc:sdmx:Glossary.Statistical data and metadata exchange.WebHome]] [[artefacts>>doc:sdmx:Glossary.Artefact.WebHome]], it is assumed that a type conversion according to the table above always happens. In case a different [[VTL>>doc:sdmx:Glossary.Validation and transformation language.WebHome]] basic scalar type is desired, it can be achieved in the [[VTL>>doc:sdmx:Glossary.Validation and transformation language.WebHome]] program taking in input the default [[VTL>>doc:sdmx:Glossary.Validation and transformation language.WebHome]] basic scalar type above and applying to it the [[VTL>>doc:sdmx:Glossary.Validation and transformation language.WebHome]] type conversion features (see the implicit and explicit type conversion and the “cast” operator in the [[VTL>>doc:sdmx:Glossary.Validation and transformation language.WebHome]] Reference Manual).
1825
1826 === 10.4.4 Mapping VTL basic scalar types to SDMX data types ===
1827
1828 The following table describes the default conversion from the [[VTL>>doc:sdmx:Glossary.Validation and transformation language.WebHome]] basic scalar types to the [[SDMX>>doc:sdmx:Glossary.Statistical data and metadata exchange.WebHome]] data types .
1829
1830 (% style="width:923.835px" %)
1831 |(% style="width:191px" %)**VTL basic scalar type**|(% style="width:419px" %)**Default SDMX data type (BasicComponentDataType)**|(% style="width:311px" %)**Default output format**
1832 |(% style="width:191px" %)**String**|(% style="width:419px" %)**String **|(% style="width:311px" %)Like XML (xs:string)
1833 |(% style="width:191px" %)**Number**|(% style="width:419px" %)**Float **|(% style="width:311px" %)Like XML (xs:float)
1834 |(% style="width:191px" %)**Integer**|(% style="width:419px" %)**Integer **|(% style="width:311px" %)Like XML (xs:int)
1835 |(% style="width:191px" %)**Date**|(% style="width:419px" %)**DateTime**|(% style="width:311px" %)YYYY-MM-DDT00:00:00Z
1836 |(% style="width:191px" %)**Time**|(% style="width:419px" %)**StandardTimePeriod**|(% style="width:311px" %)/ (as defined above)
1837 |(% style="width:191px" %)**time_period**|(% style="width:419px" %)(((
1838 **ReportingTimePeriod
1839 (StandardReportingPeriod)**
1840 )))|(% style="width:311px" %)(((
1841 YYYY-Pppp
1842 (according to [[SDMX>>doc:sdmx:Glossary.Statistical data and metadata exchange.WebHome]] )
1843 )))
1844 |(% style="width:191px" %)**Duration**|(% style="width:419px" %)**Duration **|(% style="width:311px" %)(((
1845 Like XML (xs:duration)
1846 PnYnMnDTnHnMnS
1847 )))
1848 |(% style="width:191px" %)**Boolean**|(% style="width:419px" %)**Boolean **|(% style="width:311px" %)(((
1849 Like XML (xs:boolean) with the values “true” or “false”
1850 )))
1851
1852 **Figure 14 – Mappings from SDMX data types to VTL Basic Scalar Types**
1853
1854 In case a different default conversion is desired, it can be achieved through the CustomTypeScheme and CustomType [[artefacts>>doc:sdmx:Glossary.Artefact.WebHome]] (see also the section Transformations and Expressions of the [[SDMX information model>>doc:sdmx:Glossary.SDMX Information Model.WebHome]]).
1855
1856 The custom output formats can be specified by means of the [[VTL>>doc:sdmx:Glossary.Validation and transformation language.WebHome]] formatting mask described in the section “Type Conversion and Formatting Mask” of the [[VTL>>doc:sdmx:Glossary.Validation and transformation language.WebHome]] Reference Manual. Such a section describes the masks for the [[VTL>>doc:sdmx:Glossary.Validation and transformation language.WebHome]] basic scalar types “number”, “integer”, “date”, “time”, “time_period” and “duration” and gives examples. As for the types “string” and “boolean” the [[VTL>>doc:sdmx:Glossary.Validation and transformation language.WebHome]] conventions are extended with some other special characters as described in the following table.
1857
1858 (% style="width:671.835px" %)
1859 |(% colspan="2" style="width:669px" %)**VTL special characters for the formatting masks**
1860 |(% colspan="2" style="width:669px" %)** **
1861 |(% colspan="2" style="width:669px" %)**Number **
1862 |(% style="width:141px" %)D|(% style="width:528px" %)one numeric digit (if the scientific notation is adopted, D is only for the mantissa)
1863 |(% style="width:141px" %)E|(% style="width:528px" %)one numeric digit (for the exponent of the scientific notation)
1864 |(% style="width:141px" %).(dot)|(% style="width:528px" %)possible separator between the integer and the [[decimal>>doc:sdmx:Glossary.Decimals.WebHome]] parts.
1865 |(% style="width:141px" %),(comma)|(% style="width:528px" %)possible separator between the integer and the [[decimal>>doc:sdmx:Glossary.Decimals.WebHome]] parts.
1866 |(% style="width:141px" %) |(% style="width:528px" %)
1867 |(% colspan="2" style="width:669px" %)**Time and duration**
1868 |(% style="width:141px" %)C |(% style="width:528px" %)century
1869 |(% style="width:141px" %)Y|(% style="width:528px" %)year
1870 |(% style="width:141px" %)S|(% style="width:528px" %)semester
1871 |(% style="width:141px" %)Q|(% style="width:528px" %)quarter
1872 |(% style="width:141px" %)M|(% style="width:528px" %)month
1873 |(% style="width:141px" %)W|(% style="width:528px" %)week
1874 |(% style="width:141px" %)D|(% style="width:528px" %)day
1875 |(% style="width:141px" %)h |(% style="width:528px" %)hour digit (by default on 24 hours)
1876 |(% style="width:141px" %)M|(% style="width:528px" %)minute
1877 |(% style="width:141px" %)S|(% style="width:528px" %)second
1878 |(% style="width:141px" %)D|(% style="width:528px" %)[[decimal>>doc:sdmx:Glossary.Decimals.WebHome]] of second
1879 |(% style="width:141px" %)P|(% style="width:528px" %)period indicator (representation in one digit for the duration)
1880 |(% style="width:141px" %)P|(% style="width:528px" %)number of the periods specified in the period indicator
1881 |(% style="width:141px" %)AM/PM |(% style="width:528px" %)indicator of AM / PM (e.g. am/pm for “am” or “pm”)
1882 |(% style="width:141px" %)MONTH|(% style="width:528px" %)uppercase textual representation of the month (e.g., JANUARY for January)
1883 |(% style="width:141px" %)DAY|(% style="width:528px" %)uppercase textual representation of the day (e.g., MONDAY for Monday)
1884 |(% style="width:141px" %)Month|(% style="width:528px" %)lowercase textual representation of the month (e.g., january)
1885 |(% style="width:141px" %)Day|(% style="width:528px" %)lowercase textual representation of the month (e.g., monday)
1886 |(% style="width:141px" %)Month|(% style="width:528px" %)First character uppercase, then lowercase textual representation of the month (e.g., January)
1887 |(% style="width:141px" %)Day|(% style="width:528px" %)First character uppercase, then lowercase textual [[representation>>doc:sdmx:Glossary.Representation.WebHome]] of the day using (e.g. Monday)
1888 |(% style="width:141px" %) |(% style="width:528px" %)
1889 |(% colspan="2" style="width:669px" %)**String**
1890 |(% style="width:141px" %)X|(% style="width:528px" %)any string character
1891 |(% style="width:141px" %)Z|(% style="width:528px" %)any string character from “A” to “z”
1892 |(% style="width:141px" %)9|(% style="width:528px" %)any string character from “0” to “9”
1893 |(% style="width:141px" %) |(% style="width:528px" %)
1894 |(% colspan="2" style="width:669px" %)**Boolean **
1895 |(% style="width:141px" %)B|(% style="width:528px" %)Boolean using “true” for True and “false” for False
1896 |(% style="width:141px" %)1|(% style="width:528px" %)Boolean using “1” for True and “0” for False
1897 |(% style="width:141px" %)0|(% style="width:528px" %)Boolean using “0” for True and “1” for False
1898 |(% style="width:141px" %) |(% style="width:528px" %)
1899 |(% colspan="2" style="width:669px" %)Other qualifiers
1900 |(% style="width:141px" %)*|(% style="width:528px" %)an arbitrary number of digits (of the preceding type)
1901 |(% style="width:141px" %)+|(% style="width:528px" %)at least one digit (of the preceding type)
1902 |(% style="width:141px" %)( )|(% style="width:528px" %)optional digits (specified within the brackets)
1903 |(% style="width:141px" %)\|(% style="width:528px" %)prefix for the special characters that must appear in the mask
1904 |(% style="width:141px" %)N|(% style="width:528px" %)fixed number of digits used in the preceding textual [[representation>>doc:sdmx:Glossary.Representation.WebHome]] of the month or the day
1905 |(% style="width:141px" %) |(% style="width:528px" %)
1906
1907 The default conversion, either standard or customized, can be used to deduce automatically the [[representation>>doc:sdmx:Glossary.Representation.WebHome]] of the [[components>>doc:sdmx:Glossary.Component.WebHome]] of the result of a [[VTL>>doc:sdmx:Glossary.Validation and transformation language.WebHome]] transformation. In alternative, the [[representation>>doc:sdmx:Glossary.Representation.WebHome]] of the resulting [[SDMX>>doc:sdmx:Glossary.Statistical data and metadata exchange.WebHome]] [[Dataflow>>doc:sdmx:Glossary.Dataflow.WebHome]] can be given explicitly by providing its DataStructureDefinition. In other words, the [[representation>>doc:sdmx:Glossary.Representation.WebHome]] specified in the [[DSD>>doc:sdmx:Glossary.Data structure definition.WebHome]], if available, overrides any default conversion{{footnote}}The representation given in the DSD should obviously be compatible with the VTL data type.{{/footnote}}.
1908
1909 === 10.4.5 Null Values ===
1910
1911 In the conversions from [[SDMX>>doc:sdmx:Glossary.Statistical data and metadata exchange.WebHome]] to [[VTL>>doc:sdmx:Glossary.Validation and transformation language.WebHome]] it is assumed by default that a missing value in [[SDMX>>doc:sdmx:Glossary.Statistical data and metadata exchange.WebHome]] becomes a NULL in [[VTL>>doc:sdmx:Glossary.Validation and transformation language.WebHome]]. After the conversion, the NULLs can be manipulated through the proper [[VTL>>doc:sdmx:Glossary.Validation and transformation language.WebHome]] operators.
1912
1913 On the other side, the [[VTL>>doc:sdmx:Glossary.Validation and transformation language.WebHome]] programs can produce in output NULL values for [[Measures>>doc:sdmx:Glossary.Measure.WebHome]] and [[Attributes>>doc:sdmx:Glossary.Attribute.WebHome]] (Null values are not allowed in the Identifiers). In the conversion from [[VTL>>doc:sdmx:Glossary.Validation and transformation language.WebHome]] to [[SDMX>>doc:sdmx:Glossary.Statistical data and metadata exchange.WebHome]], it is assumed that a NULL in [[VTL>>doc:sdmx:Glossary.Validation and transformation language.WebHome]] becomes a missing value in [[SDMX>>doc:sdmx:Glossary.Statistical data and metadata exchange.WebHome]].
1914
1915 In the conversion from [[VTL>>doc:sdmx:Glossary.Validation and transformation language.WebHome]] to [[SDMX>>doc:sdmx:Glossary.Statistical data and metadata exchange.WebHome]], the default assumption can be overridden, separately for each [[VTL>>doc:sdmx:Glossary.Validation and transformation language.WebHome]] basic scalar type, by specifying which the value that represents the NULL in [[SDMX>>doc:sdmx:Glossary.Statistical data and metadata exchange.WebHome]] is. This can be specified in the [[attribute>>doc:sdmx:Glossary.Attribute.WebHome]] “nullValue” of the CustomType [[artefact>>doc:sdmx:Glossary.Artefact.WebHome]] (see also the section Transformations and Expressions of the [[SDMX information model>>doc:sdmx:Glossary.SDMX Information Model.WebHome]]). A CustomType belongs to a CustomTypeScheme, which can be referenced by one or more TransformationScheme (i.e. [[VTL>>doc:sdmx:Glossary.Validation and transformation language.WebHome]] programs). The overriding assumption is applied for all the [[SDMX>>doc:sdmx:Glossary.Statistical data and metadata exchange.WebHome]] [[Dataflows>>doc:sdmx:Glossary.Dataflow.WebHome]] calculated in the TransformationScheme.
1916
1917 === 10.4.6 Format of the literals used in VTL transformations ===
1918
1919 The [[VTL>>doc:sdmx:Glossary.Validation and transformation language.WebHome]] programs can contain literals, i.e. specific values of certain data types written directly in the [[VTL>>doc:sdmx:Glossary.Validation and transformation language.WebHome]] definitions or expressions. The [[VTL>>doc:sdmx:Glossary.Validation and transformation language.WebHome]] does not prescribe a specific format for the literals and leave the specific [[VTL>>doc:sdmx:Glossary.Validation and transformation language.WebHome]] systems and the definers of [[VTL>>doc:sdmx:Glossary.Validation and transformation language.WebHome]] transformations free of using their preferred formats.
1920
1921 Given this discretion, it is essential to know which are the external [[representations>>doc:sdmx:Glossary.Representation.WebHome]] adopted for the literals in a [[VTL>>doc:sdmx:Glossary.Validation and transformation language.WebHome]] program, in order to interpret them correctly. For example, if the external format for the dates is YYYY-MM-DD the date literal 201001-02 has the meaning of 2^^nd^^ January 2010, instead if the external format for the dates is YYYY-DD-MM the same literal has the meaning of 1^^st^^ February 2010.
1922
1923 Hereinafter, i.e. in the [[SDMX>>doc:sdmx:Glossary.Statistical data and metadata exchange.WebHome]] implementation of the [[VTL>>doc:sdmx:Glossary.Validation and transformation language.WebHome]], it is assumed that the literals are expressed according to the “default output format” of the table of the previous paragraph (“Mapping [[VTL>>doc:sdmx:Glossary.Validation and transformation language.WebHome]] basic scalar types to [[SDMX>>doc:sdmx:Glossary.Statistical data and metadata exchange.WebHome]] data types”) unless otherwise specified.
1924
1925 A different format can be specified in the [[attribute>>doc:sdmx:Glossary.Attribute.WebHome]] “vtlLiteralFormat” of the CustomType [[artefact>>doc:sdmx:Glossary.Artefact.WebHome]] (see also the section Transformations and Expressions of the [[SDMX information model>>doc:sdmx:Glossary.SDMX Information Model.WebHome]]).
1926
1927 Like in the case of the conversion of NULLs described in the previous paragraph, the overriding assumption is applied, for a certain [[VTL>>doc:sdmx:Glossary.Validation and transformation language.WebHome]] basic scalar type, if a value is found for the vtlLiteralFormat [[attribute>>doc:sdmx:Glossary.Attribute.WebHome]] of the CustomType of such [[VTL>>doc:sdmx:Glossary.Validation and transformation language.WebHome]] basic scalar type. The overriding assumption is applied for all the literals of a related [[VTL>>doc:sdmx:Glossary.Validation and transformation language.WebHome]] TransformationScheme.
1928
1929 In case a literal is operand of a [[VTL>>doc:sdmx:Glossary.Validation and transformation language.WebHome]] Cast operation, the format specified in the Cast overrides all the possible otherwise specified formats.
1930
1931 = 11 Annex I: How to eliminate extra element in the .NET SDMX Web Service =
1932
1933 == 11.1 Problem statement ==
1934
1935 For implementing an [[SDMX>>doc:sdmx:Glossary.Statistical data and metadata exchange.WebHome]] compliant Web Service the standardised WSDL file should be used that describes the expected request/response structure. The request message of the operation contains a wrapper element (e.g. “GetGenericData”) that wraps a tag called “GenericDataQuery”, which is the actual [[SDMX>>doc:sdmx:Glossary.Statistical data and metadata exchange.WebHome]] query XML message that contains the query to be processed by the Web Service. In the same way the response is formulated in a wrapper element “GetGenericDataResponse”.
1936
1937 As defined in the SOAP specification, the root element of a SOAP message is the Envelope, which contains an optional Header and a mandatory Body. These are illustrated below along with the Body contents according to the WSDL:
1938
1939 [[image:1747854006117-843.png]]
1940
1941 The problem that initiated the present analysis refers to the difference in the way SOAP requests are when trying to implement the aforementioned Web Service in .NET framework.
1942
1943 Building such a Web Service using the .NET framework is done by exposing a method (i.e. the getGenericData in the example) with an XML document argument (lets name it “Query”). **The difference that appears in Microsoft .Net implementations is that there is a need for an extra XML container around the [[SDMX>>doc:sdmx:Glossary.Statistical data and metadata exchange.WebHome]] GenericDataQuery.** This is the expected behavior since the framework is let to publish automatically the Web Service as a remote procedure call, thus wraps each parameter into an extra element. The .NET request is illustrated below:
1944
1945 [[image:1747854039499-443.png]]
1946
1947 [[image:1747854067769-691.png]]
1948
1949 Furthermore this extra element is also inserted in the automatically generated WSDL from the framework. Therefore this particularity requires custom clients for the .NET Web Services that is not an interoperable solution.
1950
1951 == 11.2 Solution ==
1952
1953 The solution proposed for conforming the .NET implementation to the envisioned SOAP requests has to do with the manual intervention to the serialisation and deserialisation of the XML payloads. Since it is a Web Service of already prepared XML messages requests/responses this is the indicate way so as to have full control on the XML messages. This is the way the Java implementation (using Apache Axis) of the [[SDMX>>doc:sdmx:Glossary.Statistical data and metadata exchange.WebHome]] Web Service has adopted.
1954
1955 As regards the .NET platform this is related with the usage of **XmlAnyElement** parameter for the .NET web methods.
1956
1957 Web methods use XmlSerializer in the .NET Framework to invoke methods and build the response.
1958
1959 [[image:1747836776717-914.jpeg]]
1960
1961 The XML is passed to the XmlSerializer to de-serialize it into the instances of classes in managed [[code>>doc:sdmx:Glossary.Code.WebHome]] that (% style="color:#e74c3c" %)map(%%) to the input parameters for the Web method. Likewise, the output parameters and return values of the Web method are serialized into XML in order to create the body of the SOAP response message.
1962
1963 In case the developer wants more control over the serialization and de-serialization process a solution is represented by the usage of **XmlElement** parameters. This offers the opportunity of validating the XML against a schema before de-serializing it, avoiding de-serialization in the first place, analyzing the XML to determine how you want to de-serialize it, or using the many powerful XML APIs that are available to deal with the XML directly. This also gives the developer the control to handle errors in a particular way instead of using the faults that the XmlSerializer might generate under the covers.
1964
1965 In order to control the de-serialization process of the XmlSerializer for a Web method, **XmlAnyElement** is a simple solution to use.
1966
1967 To understand how the **XmlAnyElement** [[attribute>>doc:sdmx:Glossary.Attribute.WebHome]] works we present the following two web methods:
1968
1969 [[image:1747854096778-844.png]]
1970
1971 In this method the **input** parameter is decorated with the **XmlAnyElement** parameter. This is a hint that this parameter will be de-serialized from an **xsd:any** element. Since the [[attribute>>doc:sdmx:Glossary.Attribute.WebHome]] is not passed any parameters, it means that the entire XML element for this parameter in the SOAP message will be in the Infoset that is represented by this **XmlElement** parameter.
1972
1973 [[image:1747854127303-270.png]]
1974
1975 The difference between the two is that for the first method, **SubmitXml**, the XmlSerializer will expect an element named **input** to be an immediate child of the **SubmitXml** element in the SOAP body. The second method, **SubmitXmlAny**, will not care what the name of the child of the **SubmitXmlAny** element is. It will plug whatever XML is included into the input parameter. The message style from ASP.NET Help for the two methods is shown below. First we look at the message for the method without the **XmlAnyElement** [[attribute>>doc:sdmx:Glossary.Attribute.WebHome]].
1976
1977 [[image:1747854163928-581.png]]
1978
1979 Now we look at the message for the method that uses the **XmlAnyElement** [[attribute>>doc:sdmx:Glossary.Attribute.WebHome]].
1980
1981 [[image:1747854190641-364.png]]
1982
1983 [[image:1747854236732-512.png]]
1984
1985 The method decorated with the **XmlAnyElement** [[attribute>>doc:sdmx:Glossary.Attribute.WebHome]] has one fewer wrapping elements. Only an element with the name of the method wraps what is passed to the **input** parameter.
1986
1987 For more information please consult: [[http:~~/~~/msdn.microsoft.com/en-us/library/aa480498.aspx>>http://msdn.microsoft.com/en-us/library/aa480498.aspx]]
1988
1989 Furthermore at this point the problem with the different requests has been solved. However there is still the difference in the produced WSDL that has to be taken care. The automatic generated WSDL now doesn’t insert the extra element, but defines the content of the operation wrapper element as “xsd:any” type.
1990
1991 [[image:1747854286398-614.png]]
1992
1993 Without a common WSDL still the solution doesn’t enforce interoperability. In order to
1994
1995 “fix” the WSDL, there two approaches. The first is to intervene in the generation process. This is a complicated approach, compared to the second approach, which overrides the generation process and returns the envisioned WSDL for the [[SDMX>>doc:sdmx:Glossary.Statistical data and metadata exchange.WebHome]] Web Service.
1996
1997 This is done by redirecting the request to the “/Service?WSDL” to the envisioned WSDL stored locally into the application. To do this, from the project add a “Global Application Class” item (.asax file) and override the request in the “Application_BeginRequest” method. This is demonstrated in detail in the next section.
1998
1999 This approach has the disadvantage that for each deployment the WSDL end point has to be changed to reflect the current URL. However this inconvenience can be easily eliminated if a developer implements a simple rewriting module for changing the end point to the one of the current deployment.
2000
2001 == 11.3 Applying the solution ==
2002
2003 In the context of the [[SDMX>>doc:sdmx:Glossary.Statistical data and metadata exchange.WebHome]] Web Service, applying the above solution translates into the following:
2004
2005 [[image:1747854385465-132.png]]
2006
2007 The SOAP request/response will then be as follows:
2008
2009 **GenericData Request**
2010
2011 [[image:1747854406014-782.png]]
2012
2013 **GenericData Response**
2014
2015 [[image:1747854424488-855.png]]
2016
2017 For overriding the automatically produced WSDL, in the solution explorer right click the project and select “Add” -> “New item…”. Then select the “Global Application Class”. This will create “.asax” class file in which the following [[code>>doc:sdmx:Glossary.Code.WebHome]] should replace the existing empty method:
2018
2019 [[image:1747854453895-524.png]]
2020
2021 [[image:1747854476631-125.png]]
2022
2023 The SDMX_WSDL.wsdl should reside in the in the root directory of the application. After applying this solution the returned WSDL is the envisioned. Thus in the request message definition contains:
2024
2025 [[image:1747854493363-776.png]]
2026
2027
2028 {{putFootnotes/}}