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1 == 3.1 Introduction ==
2
3 The constructs in the SDMX Base package comprise the fundamental building blocks that support many of the other structures in the model. For this reason, many of the classes in this package are abstract (i.e., only derived sub-classes can exist in an implementation).
4
5 The motivation for establishing the SDMX Base package is as follows:
6
7 it is accepted “Best Practise” to identify fundamental archetypes occurring in a model// //identification of commonly found structures or “patterns” leads to easier understanding// //identification of patterns encourages re-use
8
9 Each of the class diagrams in this section views classes from the SDMX Base package from a different perspective. There are detailed views of specific patterns, plus overviews showing inheritance between classes, and relationships amongst classes.
10
11 === 3.2 Base Structures - Identification, Versioning, and Maintenance ===
12
13 ==== 3.2.1 Class Diagram ====
14
15 [[image:1749246130522-547.jpeg]]
16
17 **Figure 10: SDMX Identification, Maintenance and Versioning**
18
19 ===== 3.2.2 Explanation of the Diagram =====
20
21 ====== 3.2.2.1 Narrative ======
22
23 This group of classes forms the nucleus of the administration facets of SDMX objects. They provide features which are reusable by derived classes to support horizontal functionality such as identity, versioning etc.
24
25 All classes derived from the abstract class //AnnotableArtefact// may have Annotations (or notes): this supports the need to add notes to all SDMX-ML elements. The Annotation is used to convey extra information to describe any SDMX construct. This information may be in the form of a URL reference and/or a multilingual text (represented by the association to InternationalString).
26
27 The //IdentifiableArtefact// is an abstract class that comprises the basic attributes needed for identification. Concrete classes based on //IdentifiableArtefact// all inherit the ability to be uniquely identified.
28
29 The //NamableArtefact// is an abstract class that inherits from //IdentifiableArtefact //and in addition the +description and +name roles support multilingual descriptions and names for all objects based on //NameableArtefact//. The InternationalString supports the representation of a description in multiple locales (locale is similar to language but includes geographic variations such as Canadian French, US English etc.). The //LocalisedString// supports the representation of a description in one locale.
30
31 //VersionableArtefact// is an abstract class which inherits from //NameableArtefact// and adds versioning ability to all classes derived from it, as explained in the SDMX versioning rules in SDMX Standards Section 6 “Technical Notes”, paragraph “4.3 Versioning”.
32
33 //MaintainableArtefact// further adds the ability for derived classes to be maintained via its association to an //Organisation//, and adds locational information (i.e., from where the object can be retrieved).
34
35 The inheritance chain from //AnnotableArtefact// through to //MaintainableArtefact// allows SDMX classes to inherit the features they need, from simple annotation, through identity, naming, to versioning and maintenance.
36
37 ====== 3.2.2.2 Definitions ======
38
39 |**Class**|**Feature**|**Description**
40 |//AnnotableArtefact//|(((
41 Base inheritance sub classes are:
42
43 //IdentifiableArtefact//
44 )))|Objects of classes derived from this can have attached annotations.
45 |Annotation|// //|Additional descriptive information attached to an object.
46 | |id|Identifier for the Annotation. It can be used to disambiguate one Annotation from another where there are several Annotations for the same annotated object.
47 | |title|A title used to identify an annotation.
48 | |type|Specifies how the annotation is to be processed.
49 | |url|A link to external descriptive text.
50 | |value|A non-localised version of the Annotation content.
51 | |+url|An International URI provides a set of links that are language specific, via this role.
52 | |+text|An International String provides the multilingual text content of the annotation via this role.
53 |InternationalUri| |The International Uri is a collection of Localised URIs and supports linking to external descriptions in multiple locales.
54 |LocalisedUri| |The Localised URI supports the link to an external description in one locale (locale is similar to language but includes geographic variations such as Canadian French, US English etc.).
55 |//IdentifiableArtefact//|(((
56 Superclass is
57
58 //AnnotableArtefact//
59
60 Base inheritance sub classes are:
61
62 //NameableArtefact//
63 )))|Provides identity to all derived classes. It also provides annotations to derived classes because it is a subclass of Annotable Artefact.
64 | |id|The unique identifier of the object.
65 | |uri|Universal resource identifier that may or may not be resolvable.
66 | |urn|Universal resource name – this is for use in registries: all registered objects have a urn.
67 |//NameableArtefact//|(((
68 Superclass is
69
70 //IdentifiableArtefact// Base inheritance sub classes are:
71
72 //VersionableArtefact//
73 )))|Provides a Name and Description to all derived classes in addition to identification and annotations.
74 | |+description|A multi-lingual description is provided by this role via the International String class.
75 | |+name|A multi-lingual name is provided by this role via the International String class
76 |InternationalString| |The International String is a collection of Localised Strings and supports the representation of text in multiple locales.
77 |LocalisedString| |The Localised String supports the representation of text in one locale (locale is similar to language but includes geographic variations such as Canadian French, US English etc.).
78 | |label|Label of the string.
79 | |locale|The geographic locale of the string e.g French, Canadian French.
80 |//VersionableArtefact//|(((
81 Superclass is
82
83 //NameableArtefact//
84
85 Base inheritance sub classes are:
86
87 //MaintainableArtefact//
88 )))|Provides versioning information for all derived objects.
89 | |version|A version string following SDMX versioning rules.
90 | |validFrom|Date from which the version is valid
91 | |validTo|Date from which version is superseded
92 |//MaintainableArtefact//|(((
93 Inherits from
94
95 //VersionableArtefact//
96 )))|An abstract class to group together primary structural metadata artefacts that are maintained by an Agency.
97 | |isExternalReference|If set to “true” it indicates that the content of the object is held externally.
98 | |structureURL|The URL of an SDMX-ML document containing the external object.
99 | |serviceURL|The URL of an SDMX-compliant web service from which the external object can be retrieved.
100 | |+maintainer|Association to the Maintenance Agency responsible for maintaining the artefact.
101 |Agency| |See section on “Organisations”
102
103
104
105 ==== //3.3 Basic Inheritance// ====
106
107 ===== 3.3.1 Class Diagram – Basic Inheritance from the Base Inheritance Classes =====
108
109 [[image:1749246130530-261.jpeg]]
110
111 **Figure 11: Basic Inheritance from the Base Structures**
112
113 ===== 3.3.2 Explanation of the Diagram =====
114
115 ====== 3.3.2.1 Narrative ======
116
117 The diagram above shows the inheritance within the base structures. The concrete classes are introduced and defined in the specific package to which they relate.
118
119 === 3.4 Data Types ===
120
121 ==== 3.4.1 Class Diagram ====
122
123 [[image:1749246130536-128.jpeg]]
124
125 **Figure 12: Class Diagram of Basic Data Types**
126
127 ===== 3.4.2 Explanation of the Diagram =====
128
129 ====== 3.4.2.1 Narrative ======
130
131 The FacetType and FacetValueType enumerations are used to specify the valid format of the content of a non-enumerated Concept or the usage of a Concept when specified for use on a //Component// on a //Structure// (such as a Dimension in a DataStructureDefinition). The description of the various types can be found in the chapter on ConceptScheme (section 4.5).
132
133 The ActionType enumeration is used to specify the action that a receiving system should take when processing the content that is the object of the action. It is enumerated as follows:
134
135 * Append: Data or metadata is an incremental update for an existing data/metadata set or the provision of new data or documentation (attribute values) formerly absent. If any of the supplied data or metadata is already present, it will not replace that data or metadata. This corresponds to the "Update" value found in version 1.0 of the SDMX Technical Standards.
136 * Replace: Data/metadata is to be replaced and may also include additional data/metadata to be appended.
137 * Delete: Data/Metadata is to be deleted.
138 * Information: Data and metadata are for information purposes.
139
140 The ToValueType data type contains the attributes to support transformations defined in the StructureMap (see Section 0).
141
142 The ConstraintRoleType data type contains the attributes that identify the purpose of a Constraint (allowableContent, actualContent).
143
144 The ComponentRoleType data type contains the predefined Concept roles that can be assigned to any Component.
145
146 The CascadeValues data type contains the possible values for a MemberValue within a CubeRegion, in order to enable cascading to all children Codes of a selected Code, while including/excluding the latter in the selection.
147
148 The VersionType data types provides the details for versioning according to SDMX versioning rules, as explained in SDMX Standards Section 6, paragraph “4.3 Versioning”.
149
150 ==== //3.5 The Item Scheme Pattern// ====
151
152 ===== 3.5.1 Context =====
153
154 The Item Scheme is a basic architectural pattern that allows the creation of list schemes for use in simple taxonomies, for example.
155
156 The //ItemScheme// is the basis for CategoryScheme, Codelist, ConceptScheme, ReportingTaxonomy, //OrganisationScheme//, TransformationScheme, CustomTypeScheme, NamePersonalisationScheme, RulesetScheme, VtlMappingScheme and UserDefinedOperatorScheme.
157
158 ===== 3.5.2 Class Diagram =====
159
160 [[image:1749246130543-644.jpeg]]
161
162 **Figure 13 The Item Scheme pattern**
163
164 ===== 3.5.3 Explanation of the Diagram =====
165
166 ====== 3.5.3.1 Narrative ======
167
168 The //ItemScheme// is an abstract class which defines a set of //Item// (this class is also abstract). Its main purpose is to define a mechanism which can be used to create taxonomies which can classify other parts of the SDMX Information Model. It is derived from //MaintainableArtefact// which gives it the ability to be annotated, have identity, naming, versioning and be associated with an Agency. An example of a concrete class is a ConceptScheme. The associated Concepts are //Item//s.
169
170 In an exchange environment an //ItemScheme// is allowed to contain a sub-set of the //Item//s in the maintained //ItemScheme//. If such an ItemScheme is disseminated with a sub-set of the //Item//s then the fact that this is a sub-set is denoted by setting the isPartial attribute to "true".
171
172 A “partial” //ItemScheme// cannot be maintained independently in its partial form i.e., it cannot contain //Item//s that are not present in the full //ItemScheme// and the content of any one //Item //(e.g., names and descriptions) cannot deviate from the content in the full //ItemScheme//. Furthermore, the id of the //ItemScheme// where isPartial is set to "true" is the same as the id of the full //ItemScheme// (agencyId, id, version). This is important as this is the id that that is referenced in other structures (e.g., a Codelist referenced in a DSD) and this id is always the same, regardless of whether the disseminated //ItemScheme// is the full //ItemScheme// or a partial //ItemScheme//.
173
174 The purpose of a partial //ItemScheme// is to support the exchange and dissemination of a subset //ItemScheme// without the need to maintain multiple //ItemScheme//s which contain the same //Item//s. For instance, when a Codelist is used in a DataStructureDefinition it is sometimes the case that only a sub-set of the Codes in a Codelist are relevant. In this case a partial Codelist can be constructed using the Constraint mechanism explained later in this document.
175
176 //Item// inherits from //NameableArtefact// which gives it the ability to be annotated and have identity, and therefore has id, uri and urn attributes, a name and a description in the form of an InternationalString. Unlike the parent //ItemScheme//, the //Item// itself is not a //MaintainableArtefact// and therefore cannot have an independent Agency (i.e., it implicitly has the same agencyId as the //ItemScheme//).
177
178 The //Item// can be hierarchic and so one //Item// can have child //Item//s. The restriction of the hierarchic association is that a child //Item// can have only parent //Item//.
179
180 ====== 3.5.3.2 Definitions ======
181
182 |**Class**|**Feature**|**Description**
183 |//ItemScheme//|(((
184 Inherits from:
185
186 //MaintainableArtefact//
187
188 Direct sub classes are:
189
190 CategoryScheme
191
192 ConceptScheme
193
194 Codelist
195
196 ReportingTaxonomy
197
198 //OrganisationScheme//
199
200 TransformationScheme
201
202 CustomTypeScheme NamePersonalisationSc heme
203
204 RulesetScheme
205
206 VtlMappingScheme UserDefinedOperatorSc heme
207 )))|The descriptive information for an arrangement or division of objects into groups based on characteristics, which the objects have in common.
208 | |isPartial|Denotes whether the Item Scheme contains a subset of the full set of Items in the maintained scheme.
209 | |/items|Association to the Items in the scheme.
210 |//Item//|(((
211 Inherits from:
212
213 //NameableArtefact//
214
215 Direct sub classes are
216
217 Category
218
219 Concept
220
221 Code
222
223 ReportingCategory //Organisation//
224
225 Transformation
226
227 CustomType
228
229 NamePersonalisation
230
231 Ruleset
232
233 VtlMapping
234
235 UserDefinedOperator// //hierarchy
236 )))|(((
237 The Item is an item of content in an Item Scheme. This may be a node in a taxonomy or ontology, a code in a code list etc. Node that at the conceptual level the Organisation is not hierarchic.
238
239 This allows an Item optionally to have one or more child Items
240 )))
241
242 ==== //3.6 The Structure Pattern// ====
243
244 ===== 3.6.1 Context =====
245
246 The Structure Pattern is a basic architectural pattern which allows the specification of complex tabular structures which are often found in statistical data (such as Data Structure Definition, and Metadata Structure Definition). A Structure is a set of ordered lists. A pattern to underpin this tabular structure has been developed, so that commonalities between these structure definitions can be supported by common software and common syntax structures.
247
248 ===== 3.6.2 Class Diagrams [[image:1749246130548-601.jpeg]] =====
249
250 **Figure 14: The Structure Pattern**
251
252 [[image:1749246130554-995.jpeg]]
253
254 **Figure 15: Representation within the Structure Pattern**
255
256 ====== 3.6.3 Explanation of the Diagrams ======
257
258 3.6.3.1 Narrative
259
260 The //Structure// is an abstract class which contains a set of one or more //ComponentList//(s) (this class is also abstract). An example of a concrete //Structure// is DataStructureDefinition.
261
262 The //ComponentList// is a list of one or more //Component//(s//)//. The //ComponentList// has several concrete descriptor classes based on it: DimensionDescriptor, GroupDimensionDescriptor, MeasureDescriptor, and AttributeDescriptor of the DataStructureDefinition and MetadataAttributeDescriptor of the MetadataStructureDefinition.
263
264 The //Component// is contained in a //ComponentList//. The type of //Component// in a //ComponentList// is dependent on the concrete class of the ComponentList as follows:
265
266 DimensionDescriptor: Dimension, TimeDimension
267
268 GroupDimensionDescriptor: Dimension, TimeDimension
269
270 MeasureDescriptor: Measure
271
272 AttributeDescriptor: DataAttribute, MetadataAttributeRef
273
274 MetadataAttributeDescriptor: MetadataAttribute
275
276 Each //Component// takes its semantic (and possibly also its representation) from a Concept in a ConceptScheme. This is represented by the conceptIdentity association to Concept.
277
278 The //Component// may also have a localRepresentation. This allows a concrete class, such as Dimension, to specify its representation which is local to the //Structure// in which it is contained (for Dimension this will be DataStructureDefinition), and thus overrides any coreRepresentation specified for the Concept.
279
280 The Representation can be enumerated or non-enumerated. The valid content of an enumerated representation is specified either in an //ItemScheme// which can be one of Codelist, ValueList or //GeoCodelist//. The valid content of a non-enumerated representation is specified as one or more Facet(s) (for example, these may specify minimum and maximum values). For any Attribute this is achieved by one of more
281
282 ExtendedFacet(s), which allow the additional representation of XHTML.
283
284 The types of representation that are valid for specific components is expressed in the model as a constraint on the association:
285
286 * The Dimension, DataAttribute, Measure, MetadataAttribute may be enumerated and, if so, use an //EnumeratedList//.
287 * The Dimension and Measure may be non-enumerated and, if so, use one or more Facet(s), note that the FacetValueType applicable to the TimeDimension is restricted to those that represent time.
288 * The MetadataAttribute and DataAttribute may be non-enumerated and, if so, use one or more ExtendedFacet(s).
289
290 The //Structure// may be used by one or more //StructureUsage//(s). An example of this, in terms of concrete classes, is that a Dataflow (sub class of //StructureUsage//) may use a particular DataStructureDefinition (sub class of //Structure//), and similar constructs apply for the Metadataflow (link to MetadataStructureDefinition).
291
292 3.6.3.2 Definitions
293
294 |**Class**|**Feature**|**Description**
295 |StructureUsage|(((
296 Inherits from:
297
298 //MaintainableArtefact//
299
300 Sub classes are:
301
302 Dataflow
303
304 Metadataflow
305 )))|An artefact whose components are described by a Structure. In concrete terms (sub-classes) an example would be a Dataflow which is linked to a given structure – in this case the Data Structure Definition.
306 | |structure|An association to a Structure specifying the structure of the artefact.
307 |Structure|(((
308 Inherits from:
309
310 //MaintainableArtefact//
311
312 Sub classes are:
313
314 DataStructureDefinition MetadataStructureDefinit ion
315 )))|Abstract specification of a list of lists to define a complex tabular structure. A concrete example of this would be statistical concepts, code lists, and their organisation in a data or metadata structure definition, defined by a centre institution, usually for the exchange of statistical information with its partners.
316 | |grouping|A composite association to one or more component lists.
317 |//ComponentList//|(((
318 Inherits from:
319
320 //IdentifiableArtefact//
321
322 Sub classes are:
323
324 DimensionDescriptor
325
326 GroupDimensionDescriptor
327
328 MeasureDescriptor
329
330 AttributeDescriptor MetadataAttributeDescrip tor
331 )))|An abstract definition of a list of components. A concrete example is a Dimension Descriptor, which defines the list of Dimensions in a Data Structure Definition.
332 | |components|An aggregate association to one or more components which make up the list.
333 |//Component//|(((
334 Inherits from:
335
336 //IdentifiableArtefact//
337
338 Sub classes are:
339
340 Measure
341
342 //AttributeComponent//
343
344 //DimensionComponent//
345 )))|A Component is an abstract super class used to define qualitative and quantitative data and metadata items that belong to a Component List and hence a Structure. Component is refined through its sub-classes.
346 | |conceptIdentity|Association to a Concept in a Concept Scheme that identifies and defines the semantic of the Component.
347 | |localRepresentation|(((
348 Association to the Representation of the Component if this is different from the coreRepresentation of the
349
350 Concept, which the Component uses (ConceptUsage).
351 )))
352 |Representation| |The allowable value or format for Component or Concept
353 | |+enumerated|Association to an enumerated list that contains the allowable content for the Component when reported in a data or metadata set. The type of enumerated list that is allowed for any concrete Component is shown in the constraints on the association.
354 | |+nonEnumerated|Association to a set of Facets that define the allowable format for the content of the Component when reported in a data or metadata set.
355 |Facet| |Defines the format for the content of the Component when reported in a data or metadata set.
356 | |facetType|A specific content type, which is constrained by the Facet Type enumeration.
357 | |facetValueType|The format of the value of a Component when reported in a data or metadata set. This is constrained by the Facet Value Type enumeration.
358 | |+itemSchemeFacet|Defines the format of the identifiers in an Item Scheme used by a Component. Typically, this would define the number of characters (length) of the identifier.
359 |ExtendedFacet| |This has the same function as Facet but allows additionally an XHTML representation. This is constrained for use with a Metadata Attribute and a Data Attribute.
360
361 The specification of the content and use of the sub classes to //ComponentList// and //Component// can be found in the section in which they are used (DataStructureDefinition and MetadataStructureDefinition). Moreover, the FacetType SentinelValues is explained in the datastructure representation diagram (see 5.3.2.2), since it only concerns DataStructureDefinitions.
362
363 3.6.3.3 Representation Constructs
364
365 The majority of SDMX FacetValueTypes are compatible with those found in XML Schema, and have equivalents in most current implementation platforms:
366
367 |(((
368 **SDMX Facet**
369
370 **Value Type**
371 )))|**XML Schema Data Type**|**JSON Schema Data Type**|(((
372 **.NET Framework**
373
374 **Type**
375 )))|**Java Data Type**
376 |String|xsd:string|string|System.String|java.lang.String
377 |Big Integer|xsd:integer|integer|System.Decimal|java.math.BigInteger
378 |Integer|xsd:int|integer|System.Int32|int
379 |Long|xsd.long|integer|System.Int64|long
380 |Short|xsd:short|integer|System.Int16|short
381 |Decimal|xsd:decimal|number|System.Decimal|java.math.BigDecimal
382 |Float|xsd:float|number|System.Single|float
383 |Double|xsd:double|number|System.Double|double
384 |Boolean|xsd:boolean|boolean|System.Boolean|boolean
385 |URI|xsd:anyURI|string:uri|System.Uri|Java.net.URI or java.lang.String
386 |DateTime|xsd:dateTime|string:datetime|System.DateTime|javax.xml.datatype.XML GregorianCalendar
387 |Time|xsd:time|string:time|System.DateTime|javax.xml.datatype.XML GregorianCalendar
388 |GregorianYear|xsd:gYear|string[[^^~[1~]^^>>path:#_ftn1]]|System.DateTime|javax.xml.datatype.XML GregorianCalendar
389 |GregorianMonth|xsd:gYearMonth|string|System.DateTime|javax.xml.datatype.XML GregorianCalendar
390 |GregorianDay|xsd:date|string|System.DateTime|javax.xml.datatype.XML GregorianCalendar
391 |Day, MonthDay, Month|xsd:g*|string|System.DateTime|javax.xml.datatype.XML GregorianCalendar
392 |Duration|xsd:duration|string|System.TimeSpan|javax.xml.datatype.Dur ation
393
394 There are also a number of SDMX data types which do not have these direct correspondences, often because they are composite representations or restrictions of a broader data type. These are detailed in Section 6 of the standards.
395
396 The Representation is composed of Facets, each of which conveys characteristic information related to the definition of a value domain. Often a set of Facets are needed to convey the required semantic. For example, a sequence is defined by a minimum of two Facets: one to define the start value, and one to define the interval.
397
398
399 |**Facet Type**|**Explanation**
400 |isSequence|The isSequence facet indicates whether the values are intended to be ordered, and it may work in combination with the interval, startValue,and endValue facet or the timeInterval, startTime, and endTime, facets. If this attribute holds a value of true, a start value or time and a numeric or time interval must be supplied. If an end value is not given, then the sequence continues indefinitely.
401 |interval|The interval attribute specifies the permitted interval (increment) in a sequence. In order for this to be used, the isSequence attribute must have a value of true.
402 |startValue|The startValue facet is used in conjunction with the isSequence and interval facets (which must be set in order to use this facet). This facet isused for a numeric sequence and indicates the starting point of the sequence. This value is mandatory for a numeric sequence to be expressed.
403 |endValue|The endValue facet is used in conjunction with the isSequence and interval facets (which must be set in order to use this facet). This facet is used for a numeric sequence and indicates that ending point (if any) of the sequence.
404 |timeInterval|The timeInterval facet indicates the permitted duration in a time sequence. In order for this to be used, the isSequence facet must have a value of true.
405 |startTime|The startTime facet is used in conjunction with the isSequence and timeInterval facets (which must be set in order to use this facet). Thisnattribute is used for a time sequence and indicates the start time of thensequence. This value is mandatory for a time sequence to be expressed.
406 |endTime|The endTime facet is used in conjunction with the isSequence and timeInterval facets (which must be set in order to use this facet). This facet is used for a time sequence and indicates that ending point (if any) ofnthe sequence.
407 |minLength|The minLength facet specifies the minimum and length of the value in characters.
408 |maxLength|The maxLength facet specifies the maximum length of the value in characters.
409 |minValue|The minValue facet is used for inclusive and exclusive ranges, indicating what the lower bound of the range is. If this is used with an inclusive range, a valid value will be greater than or equal to the value specified here. If the inclusive and exclusive data type is not specified (e.g., this facet is used with an integer data type), the value is assumed to be inclusive.
410 |maxValue|The maxValue facet is used for inclusive and exclusive ranges, indicating what the upper bound of the range is. If this is used with an inclusive range, a valid value will be less than or equal to the value specified here. If the inclusive and exclusive data type is not specified (e.g., this facet is used with an integer data type), the value is assumed to be inclusive.
411 |Decimals|The decimals facet indicates the number of characters allowed after the decimal separator.
412 |pattern|The pattern attribute holds any regular expression permitted in the implementation syntax (e.g., W3C XML Schema).
413
414
415
416 ----
417
418 [[~[1~]>>path:#_ftnref1]] In the JSON schemas, more complex data types are complemented with regular expressions, whenever no direct mapping to a standard type exists.