Changes for page SDMX 3.0 Standards. Section 1. Framework for SDMX technical standards

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1		-Artefact\|Metadata set\|Reference metadata\|SDMX Information Model\|SDMX Technical Specification\|SDMX-JSON\|SDMX-ML\|Statistical data and metadata exchange\|Statistical subject-matter domain\|Structural metadata\|Validation and transformation language

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  = 1 Introduction =
--The [[Statistical Data and Metadata Exchange>>doc:xwiki:Glossary.Statistical data and metadata exchange.WebHome]] ([[SDMX>>doc:xwiki:Glossary.Statistical data and metadata exchange.WebHome]]) initiative (https:~/~/www.[[sdmx>>doc:xwiki:Glossary.Statistical data and metadata exchange.WebHome]].org) sets 3 standards that can facilitate the exchange of statistical data and metadata using modern 4 information technology.
++The Statistical Data and Metadata Exchange (SDMX) initiative (https:~/~/www.sdmx.org) sets 3 standards that can facilitate the exchange of statistical data and metadata using modern 4 information technology.
--The [[SDMX Technical Specifications>>doc:xwiki:Glossary.SDMX Technical Specification.WebHome]] are organised into several discrete sections.
++The SDMX Technical Specifications are organised into several discrete sections.
--The following are published on the [[SDMX>>doc:xwiki:Glossary.Statistical data and metadata exchange.WebHome]] website
++The following are published on the SDMX website ([[__https:~~/~~/www.sdmx.org__>>https://https:www.sdmx.org]]).
--([[__https:~~/~~/www.sdmx.org__>>https://https:www.sdmx.org]]).
--
  **Section 1** **Framework for SDMX Technical Standards** – this document providing an introduction to the technical standards.
--**Section 2** **SDMX Information Model** -
++**Section 2** **SDMX Information Model** - the SDMX information model is a standardised object model for modelling statistical domains centring on the structure of their data and metadata sets, the coding schemes used for classification, and the rules for controlling the exchange of data and metadata between organisations. This document provides a UML specification with supporting narrative.
--the [[SDMX information model>>doc:xwiki:Glossary.SDMX Information Model.WebHome]] is a standardised object model for modelling [[statistical domains>>doc:xwiki:Glossary.Statistical subject-matter domain.WebHome]] centring on the structure of their data and [[metadata sets>>doc:xwiki:Glossary.Metadata set.WebHome]], the coding schemes used for classification, and the rules for controlling the exchange of data and metadata between organisations. This document provides a UML specification with supporting narrative.
++**Section 5** **SDMX Registry Specification** – an SDMX ‘registry’ acts as a repository for structural metadata and provisioning information, and a registry of data and metadata sources. This document sets out the specification.
--**Section 5** **SDMX Registry Specification** – an [[SDMX>>doc:xwiki:Glossary.Statistical data and metadata exchange.WebHome]] ‘registry’ acts as a repository for [[structural metadata>>doc:xwiki:Glossary.Structural metadata.WebHome]] and provisioning information, and a registry of data and metadata sources. This document sets out the specification.
++**Section 6** **SDMX Technical Notes** – detailed technical guidance for implementors of the SDMX standard.
--**Section 6** **SDMX Technical Notes** – detailed technical guidance for implementors of the [[SDMX>>doc:xwiki:Glossary.Statistical data and metadata exchange.WebHome]] standard.
++The following are published on the GitHub repository of the SDMX Standards Technical Working Group ( __[[https:~~/~~/github.com/sdmx-twg>>https://github.com/sdmx-twg]]) :__
--The following are published on the GitHub repository of the [[SDMX>>doc:xwiki:Glossary.Statistical data and metadata exchange.WebHome]] Standards Technical Working Group ([[__https:~~/~~/github.com/sdmx-twg__>>https://https:github.comsdmx-twg]]):
--
  (% class="wikigeneratedid" id="Hsdmx-twg2Fsdmx-rest2013RESTAPI" %)
  **sdmx-twg/sdmx-rest – REST API**
--Technical specifications for the [[SDMX>>doc:xwiki:Glossary.Statistical data and metadata exchange.WebHome]] RESTful web services application programming interfaces (API).
++Technical specifications for the SDMX RESTful web services application programming interfaces (API).
  (% class="wikigeneratedid" id="Hsdmx-twg2Fsdmx-ml2013SDMX-ML" %)
--**sdmx-twg/sdmx-ml – [[SDMX-ML>>doc:xwiki:Glossary.SDMX-ML.WebHome]]**
++**sdmx-twg/sdmx-ml – SDMX-ML**
--Technical specifications for the XML transmission format including XSD schemas, documentation and samples for data, structure and [[reference metadata>>doc:xwiki:Glossary.Reference metadata.WebHome]] messages.
++Technical specifications for the XML transmission format including XSD schemas, documentation and samples for data, structure and reference metadata messages.
  (% class="wikigeneratedid" id="Hsdmx-twg2Fsdmx-json2013SDMX-JSON" %)
--**sdmx-twg/sdmx-json – [[SDMX-JSON>>doc:xwiki:Glossary.SDMX-JSON.WebHome]]**
++**sdmx-twg/sdmx-json – SDMX-JSON**
--Technical specifications for the JSON transmission format including documentation, schemas and samples for data, structure and [[reference metadata>>doc:xwiki:Glossary.Reference metadata.WebHome]] messages.
++Technical specifications for the JSON transmission format including documentation, schemas and samples for data, structure and reference metadata messages.
  (% class="wikigeneratedid" id="Hsdmx-twg2Fsdmx-csv2013SDMX-CSV" %)
--**sdmx-twg/sdmx-csv – [[SDMX>>doc:xwiki:Glossary.Statistical data and metadata exchange.WebHome]]-CSV**
++**sdmx-twg/sdmx-csv – SDMX-CSV**
--Technical specifications for the [[SDMX>>doc:xwiki:Glossary.Statistical data and metadata exchange.WebHome]]-CSV transmission format for ‘comma-separated values’ (CSV) data and [[reference metadata>>doc:xwiki:Glossary.Reference metadata.WebHome]].
++Technical specifications for the SDMX-CSV transmission format for ‘comma-separated values’ (CSV) data and reference metadata.
  The following sections are obsolete:
--Section 3 - [[SDMX-ML>>doc:xwiki:Glossary.SDMX-ML.WebHome]] - replaced by the [[sdmx>>doc:xwiki:Glossary.Statistical data and metadata exchange.WebHome]]-twg/[[sdmx-ml>>doc:xwiki:Glossary.SDMX-ML.WebHome]] GitHub repository
++Section 3 - SDMX-ML - replaced by the sdmx-twg/sdmx-ml GitHub repository
--Section 4 - [[SDMX>>doc:xwiki:Glossary.Statistical data and metadata exchange.WebHome]]-EDI
++Section 4 - SDMX-EDI
--Section 7 - API - replaced by the [[sdmx>>doc:xwiki:Glossary.Statistical data and metadata exchange.WebHome]]-twg/[[sdmx>>doc:xwiki:Glossary.Statistical data and metadata exchange.WebHome]]-rest GitHub repository [[VTL>>doc:xwiki:Glossary.Validation and transformation language.WebHome]]
++Section 7 - API - replaced by the sdmx-twg/sdmx-rest GitHub repository VTL
--In July 2020 the [[SDMX>>doc:xwiki:Glossary.Statistical data and metadata exchange.WebHome]] 2.1 specifications were revised to add support for the [[Validation and Transformation Language>>doc:xwiki:Glossary.Validation and transformation language.WebHome]] ([[VTL>>doc:xwiki:Glossary.Validation and transformation language.WebHome]]). For 3.0, the [[VTL>>doc:xwiki:Glossary.Validation and transformation language.WebHome]] specification has been updated to align with changes to the information model and other modifications to the Standard such as the introduction of Semantic Versioning for the versioning of [[structural metadata>>doc:xwiki:Glossary.Structural metadata.WebHome]] [[artefacts>>doc:xwiki:Glossary.Artefact.WebHome]]. Section 2 (Information Model) sets out details of the ‘Transformation and Expressions’ package for defining and managing [[VTL>>doc:xwiki:Glossary.Validation and transformation language.WebHome]] 2.0 programs and Section 6 (Technical Notes) provides detailed guidance on implementing and using [[VTL>>doc:xwiki:Glossary.Validation and transformation language.WebHome]] with [[SDMX>>doc:xwiki:Glossary.Statistical data and metadata exchange.WebHome]].
++In July 2020 the SDMX 2.1 specifications were revised to add support for the Validation and Transformation Language (VTL). For 3.0, the VTL specification has been updated to align with changes to the information model and other modifications to the Standard such as the introduction of Semantic Versioning for the versioning of structural metadata artefacts. Section 2 (Information Model) sets out details of the ‘Transformation and Expressions’ package for defining and managing VTL 2.0 programs and Section 6 (Technical Notes) provides detailed guidance on implementing and using VTL with SDMX.
  = 2 Change History =
--The 2.0 (% style="color:#2ecc71" %)version(%%) of this standard represented a significant increase in scope, and also provided more complete support in those areas covered in the (% style="color:#2ecc71" %)version(%%) 1.0 specification. (% style="color:#2ecc71" %)Version(%%) 2.0 of this standard is backward-compatible with (% style="color:#2ecc71" %)version(%%) 1.0, so that existing implementations can be easily migrated to conformance with (% style="color:#2ecc71" %)version(%%) 2.0.
++The 2.0 version of this standard represented a significant increase in scope, and also provided more complete support in those areas covered in the version 1.0 specification. Version 2.0 of this standard is backward-compatible with version 1.0, so that existing implementations can be easily migrated to conformance with version 2.0.
--The 2.1 (% style="color:#2ecc71" %)version(%%) of this standard represents a set of changes resulting from several years of implementation experience with the 2.0 standard. The changes do not represent a major increase in scope or functionality, but do correct some bugs, and add functionalities in some cases. Major changes in [[SDMX-ML>>doc:xwiki:Glossary.SDMX-ML.WebHome]] include a much stronger alignment of the XML Schemas with the Information Model, to emphasize inheritance and object-oriented features, and increased precision and flexibility in the attachment of metadata reports to specific objects in the [[SDMX>>doc:xwiki:Glossary.Statistical data and metadata exchange.WebHome]] Information Model.
++The 2.1 version of this standard represents a set of changes resulting from several years of implementation experience with the 2.0 standard. The changes do not represent a major increase in scope or functionality, but do correct some bugs, and add functionalities in some cases. Major changes in SDMX-ML include a much stronger alignment of the XML Schemas with the Information Model, to emphasize inheritance and object-oriented features, and increased precision and flexibility in the attachment of metadata reports to specific objects in the SDMX Information Model.
--The 3.0 (% style="color:#2ecc71" %)version(%%) incorporates new features, improvements and changes arising from the collective knowledge gained from a decade of operating experience with the 2.1 standard. In pursuit of modernisation and simplification, features considered obsolete have been deprecated – in particular the EDI transmission format, the lesser-used XML data messages and the SOAP web services API. Many areas remain backwardly compatible with 2.1, but there are some breaking changes where the information model has been redesigned to better support practical use case. Structure mapping and [[reference metadata>>doc:xwiki:Glossary.Reference metadata.WebHome]] are examples. The opportunity has been taken to revise the RESTful web services API which is also not backwardly compatible, but benefits from a rationalisation and better organisations of resources, and a much richer data query URL syntax.
++The 3.0 version incorporates new features, improvements and changes arising from the collective knowledge gained from a decade of operating experience with the 2.1 standard. In pursuit of modernisation and simplification, features considered obsolete have been deprecated – in particular the EDI transmission format, the lesser-used XML data messages and the SOAP web services API. Many areas remain backwardly compatible with 2.1, but there are some breaking changes where the information model has been redesigned to better support practical use case. Structure mapping and reference metadata are examples. The opportunity has been taken to revise the RESTful web services API which is also not backwardly compatible, but benefits from a rationalisation and better organisations of resources, and a much richer data query URL syntax.
  == 2.1 Major Changes from 1.0 to 2.0 ==
--* **[[Reference Metadata>>doc:xwiki:Glossary.Reference metadata.WebHome]]**: In addition to describing and specifying data structures and formats (along with related [[structural metadata>>doc:xwiki:Glossary.Structural metadata.WebHome]]), the (% style="color:#2ecc71" %)version(%%) 2.0 specification also provides for the exchange of metadata which is distinct from the [[structural metadata>>doc:xwiki:Glossary.Structural metadata.WebHome]] in the 1.0 (% style="color:#2ecc71" %)version(%%). This [[category>>doc:xwiki:Glossary.Category.WebHome]] includes “reference” metadata (regarding data quality, methodology, and similar types – it can be configured by the user to include whatever (% style="color:#2ecc71" %)concepts(%%) require reporting); metadata related to data provisioning ([[release calendar>>doc:xwiki:Glossary.Release policy - release calendar.WebHome]] information, description of the data and metadata provided, etc.); and metadata relevant to the exchange of categorization schemes.
++* **Reference Metadata**: In addition to describing and specifying data structures and formats (along with related structural metadata), the version 2.0 specification also provides for the exchange of metadata which is distinct from the structural metadata in the 1.0 version. This category includes “reference” metadata (regarding data quality, methodology, and similar types – it can be configured by the user to include whatever concepts require reporting); metadata related to data provisioning (release calendar information, description of the data and metadata provided, etc.); and metadata relevant to the exchange of categorization schemes.
  * **SDMX Registry**: Provision is made in the 2.0 standard for standard communication with registry services, to support a data-sharing model of statistical exchange. These services include registration of data and metadata, querying of registered data and metadata, and subscription.
--* **[[Structural Metadata>>doc:xwiki:Glossary.Structural metadata.WebHome]]**: The support for exchange of statistical data and related [[structural metadata>>doc:xwiki:Glossary.Structural metadata.WebHome]] has been expanded. Some support is provided for qualitative data; data cube structures are described; [[hierarchical code lists>>doc:xwiki:Glossary.Hierarchical code list.WebHome]] are supported; relationships between data structures can be expressed, providing support for extensibility of data structures; 101 and the description of functional dependencies within cubes are supported.
++* **Structural Metadata**: The support for exchange of statistical data and related structural metadata has been expanded. Some support is provided for qualitative data; data cube structures are described; hierarchical code lists are supported; relationships between data structures can be expressed, providing support for extensibility of data structures; 101 and the description of functional dependencies within cubes are supported.
  == 2.2 Major Changes from 2.0 to 2.1 ==
--* **Simplification of the [[data structure definition>>doc:xwiki:Glossary.Data structure definition.WebHome]] - specific message types:** Both time series ((% style="color:#2ecc71" %)version(%%) 2.0 Compact) and non-time series [[data sets>>doc:xwiki:Glossary.Data set.WebHome]] ((% style="color:#2ecc71" %)version(%%) 2.0 Cross Sectional) use the same underlying structure for a structure-specific formatted message, which is specific to the [[Data Structure Definition>>doc:xwiki:Glossary.Data structure definition.WebHome]] of the data set.
++* **Simplification of the data structure definition - specific message types:** Both time series (version 2.0 Compact) and non-time series data sets (version 2.0 Cross Sectional) use the same underlying structure for a structure-specific formatted message, which is specific to the Data Structure Definition of the data set.
  * **Simplification and better support for the metadata structure: **New use cases have been reported and these are now supported by a re-modelled metadata structure definition.
--* **Web-Services-Oriented Changes:** Several organizations have been implementing web services applications using [[SDMX>>doc:xwiki:Glossary.Statistical data and metadata exchange.WebHome]], and these implementations have resulted in several changes to the specifications. Because the nature of [[SDMX>>doc:xwiki:Glossary.Statistical data and metadata exchange.WebHome]] web services could not be anticipated at the time of the original drafting of the specifications, the web services guidelines have been completely re-developed.
--* **Presentational Changes: **Much work has gone into using various technologies for the visualization of [[SDMX>>doc:xwiki:Glossary.Statistical data and metadata exchange.WebHome]] data and metadata, and some changes have been proposed as a result, to better leverage this graphical visualization. These changes are largely to leverage the [[Cross-domain Concepts>>doc:xwiki:Glossary.Cross-domain concept.WebHome]] of the Content Oriented Guidelines.
++* **Web-Services-Oriented Changes:** Several organizations have been implementing web services applications using SDMX, and these implementations have resulted in several changes to the specifications. Because the nature of SDMX web services could not be anticipated at the time of the original drafting of the specifications, the web services guidelines have been completely re-developed.
++* **Presentational Changes: **Much work has gone into using various technologies for the visualization of SDMX data and metadata, and some changes have been proposed as a result, to better leverage this graphical visualization. These changes are largely to leverage the Cross-domain Concepts of the Content Oriented Guidelines.
  * **Consistency Issues:** There have been some areas where the draft specifications were inconsistent in minor ways, and these have been addressed.
  * **Clarifications in Documentation:** In some cases, it has been identified that the documentation of specific fields within the standard needed clarification and elaboration, and these issues have been addressed.
--* **Optimization for XML Technologies:** Implementation has shown that it is possible to better organize the XML schemas for use within common technology development tools which work with XML. These changes are primarily focused on leveraging the object oriented features of W3C XML Schema to allow for easier processing of [[SDMX>>doc:xwiki:Glossary.Statistical data and metadata exchange.WebHome]] data and metadata.
--* **Consistency between the [[SDMX-ML>>doc:xwiki:Glossary.SDMX-ML.WebHome]] and the [[SDMX Information Model>>doc:xwiki:Glossary.SDMX Information Model.WebHome]]: **Certain aspects of the XML schemas and UML model have been more closely aligned, to allow for easier comprehension of the [[SDMX>>doc:xwiki:Glossary.Statistical data and metadata exchange.WebHome]] model.
++* **Optimization for XML Technologies:** Implementation has shown that it is possible to better organize the XML schemas for use within common technology development tools which work with XML. These changes are primarily focused on leveraging the object oriented features of W3C XML Schema to allow for easier processing of SDMX data and metadata.
++* **Consistency between the SDMX-ML and the SDMX Information Model: **Certain aspects of the XML schemas and UML model have been more closely aligned, to allow for easier comprehension of the SDMX model.
  * **Technical Bugs:** Some minor technical bugs have been identified in the registry interfaces and elsewhere. These bugs have been addressed.
  * **Support for Non-Time-Series Data in the Generic Format: **One area which has been extended is the ability to express non-time-series data as part of the generic data message.
--* **Support for partial [[item schemes>>doc:xwiki:Glossary.Item scheme.WebHome]] such as a [[code list>>doc:xwiki:Glossary.Code list.WebHome]]: **The (% style="color:#2ecc71" %)concept(%%) of a partial (sub set) [[item scheme>>doc:xwiki:Glossary.Item scheme.WebHome]] such as a partial [[code list>>doc:xwiki:Glossary.Code list.WebHome]] for use in exchange scenarios has been introduced**.**
++* **Support for partial item schemes such as a code list: **The concept of a partial (sub set) item scheme such as a partial code list for use in exchange scenarios has been introduced**.**
  == 2.3 Major Changes from 2.1 to 3.0 ==
--[[SDMX>>doc:xwiki:Glossary.Statistical data and metadata exchange.WebHome]] (% style="color:#2ecc71" %)version(%%) 3.0 introduces new features, improvements and changes to the Standard in the following key areas:
++SDMX version 3.0 introduces new features, improvements and changes to the Standard in the following key areas:
--(% class="wikigeneratedid" id="HInformationModel" %)
--**Information Model**
++=== Information Model ===
--* Simplification and improvement of the [[reference metadata>>doc:xwiki:Glossary.Reference metadata.WebHome]] model
++* Simplification and improvement of the reference metadata model
  * Support for microdata
  * Support for geospatial data
--* Support for [[code list>>doc:xwiki:Glossary.Code list.WebHome]] extension and discriminated union of [[code>>doc:xwiki:Glossary.Code.WebHome]] lists
++* Support for code list extension and discriminated union of code lists
  * Improvements to structure mapping
--* Improvements to [[code>>doc:xwiki:Glossary.Code.WebHome]] [[hierarchies>>doc:xwiki:Glossary.Hierarchy.WebHome]] for data discovery
++* Improvements to code hierarchies for data discovery
  * Improvements to constraints
--(% class="wikigeneratedid" id="HVersioningofStructuralMetadataArtefacts" %)
--**Versioning of Structural Metadata Artefacts**
++=== Versioning of Structural Metadata Artefacts ===
--* Adoption of the three-number semantic versioning standard for [[structural metadata>>doc:xwiki:Glossary.Structural metadata.WebHome]] [[artefacts>>doc:xwiki:Glossary.Artefact.WebHome]] (__[[https:~~/~~/semver.org>>url:https://semver.org/]])__
++* Adoption of the three-number semantic versioning standard for structural metadata artefacts (__[[https:~~/~~/semver.org>>url:https://semver.org/]])__
--(% class="wikigeneratedid" id="HRESTWebServicesApplicationProgrammingInterface28API29" %)
--**REST Web Services Application Programming Interface (API)**
++=== REST Web Services Application Programming Interface (API) ===
  * Change to a single ‘structure’ resource for structure queries simplifying the REST API specification by reducing the number of resources to five
  * Improvements to data queries
--* Improvements to [[reference metadata>>doc:xwiki:Glossary.Reference metadata.WebHome]] queries
--* Support for [[structural metadata>>doc:xwiki:Glossary.Structural metadata.WebHome]] maintenance using HTTP PUT, POST and DELETE verbs
++* Improvements to reference metadata queries
++* Support for structural metadata maintenance using HTTP PUT, POST and DELETE verbs
--(% class="wikigeneratedid" id="HSOAPWebServicesAPI" %)
--**SOAP Web Services API**
++=== SOAP Web Services API ===
--* The SOAP web services API has been deprecated with (% style="color:#2ecc71" %)version(%%) 3.0 standardising on REST
++* The SOAP web services API has been deprecated with version 3.0 standardising on REST
--(% class="wikigeneratedid" id="HXML2CJSON2CCSVandEDITransmissionformats" %)
--**XML, JSON, CSV and EDI Transmission formats**
++=== XML, JSON, CSV and EDI Transmission formats ===
--* The [[SDMX-ML>>doc:xwiki:Glossary.SDMX-ML.WebHome]], [[SDMX-JSON>>doc:xwiki:Glossary.SDMX-JSON.WebHome]] and [[SDMX>>doc:xwiki:Glossary.Statistical data and metadata exchange.WebHome]]-CSV specifications have been extended and modified where needed to support the new features and changes such as [[reference metadata>>doc:xwiki:Glossary.Reference metadata.WebHome]] and microdata
--* Obsolete [[SDMX-ML>>doc:xwiki:Glossary.SDMX-ML.WebHome]] data message variants including Generic, Compact, Utility and Cross-sectional have been deprecated standardising on Structure Specific Data as the sole XML format for data exchange
--* The [[SDMX-EDI>>doc:xwiki:Glossary.SDMX-EDI.WebHome]] transmission format for structures and data has been deprecated
--* The organisation of structures into ‘collections’ in [[SDMX-ML>>doc:xwiki:Glossary.SDMX-ML.WebHome]] and [[SDMX-JSON>>doc:xwiki:Glossary.SDMX-JSON.WebHome]] structure messages has been flattened and simplified
--* The option to reference structures in [[SDMX-ML>>doc:xwiki:Glossary.SDMX-ML.WebHome]] and [[SDMX-JSON>>doc:xwiki:Glossary.SDMX-JSON.WebHome]] messages using Agency, ID and (% style="color:#2ecc71" %)Version(%%) has been deprecated with URN now exclusively used for all non-local referencing purpose
++* The SDMX-ML, SDMX-JSON and SDMX-CSV specifications have been extended and modified where needed to support the new features and changes such as reference metadata and microdata
++* Obsolete SDMX-ML data message variants including Generic, Compact, Utility and Cross-sectional have been deprecated standardising on Structure Specific Data as the sole XML format for data exchange
++* The SDMX-EDI transmission format for structures and data has been deprecated
++* The organisation of structures into ‘collections’ in SDMX-ML and SDMX-JSON structure messages has been flattened and simplified
++* The option to reference structures in SDMX-ML and SDMX-JSON messages using Agency, ID and Version has been deprecated with URN now exclusively used for all non-local referencing purpose
--Several of the changes are ‘breaking’ meaning that, in specific cases, the (% style="color:#2ecc71" %)version(%%) 3.0 specification is not backwardly compatible with earlier (% style="color:#2ecc71" %)versions(%%) of the Standard.
++Several of the changes are ‘breaking’ meaning that, in specific cases, the version 3.0 specification is not backwardly compatible with earlier versions of the Standard.
  The principle breaking changes are:
  * REST API – The REST API is not backwardly compatible due to modifications to the URLs and query parameters resulting in breaking changes in four of the five main resources.
--* SOAP API – Deprecation of the SOAP API means that existing systems designed to use SOAP will not work with (% style="color:#2ecc71" %)version(%%) 3.0 registries.
--* [[SDMX-ML>>doc:xwiki:Glossary.SDMX-ML.WebHome]] – [[SDMX>>doc:xwiki:Glossary.Statistical data and metadata exchange.WebHome]] 2.1 and earlier structure, data and metadata XML messages are not valid in (% style="color:#2ecc71" %)version(%%) 3.0. Specifically: legacy data messages including Generic, Compact and Utility are no longer supported. The remaining Structure Specific data message has been changed to support new features such as reporting of [[reference metadata>>doc:xwiki:Glossary.Reference metadata.WebHome]] as part of the [[dataset>>doc:xwiki:Glossary.Data set.WebHome]], Structure messages have a number of breaking changes, principally modification to the information model, removal of the agency-(% style="color:#2ecc71" %)version(%%)-id option for referencing [[artefacts>>doc:xwiki:Glossary.Artefact.WebHome]] and changes to the way the structures are organised into ‘collections’ within the message.
--* [[SDMX-JSON>>doc:xwiki:Glossary.SDMX-JSON.WebHome]] – [[SDMX>>doc:xwiki:Glossary.Statistical data and metadata exchange.WebHome]] 2.1 structure, data and metadata JSON messages are not valid in (% style="color:#2ecc71" %)version(%%) 3.0. The data message has been changed to support the improved REST data queries, in particular the ability to retrieve in one operation data from multiple [[datasets>>doc:xwiki:Glossary.Data set.WebHome]] with potentially different [[Data Structure Definitions>>doc:xwiki:Glossary.Data structure definition.WebHome]]. Breaking changes similar to those for the [[SDMX-ML>>doc:xwiki:Glossary.SDMX-ML.WebHome]] transmission format have been made to the structure message.
--* [[SDMX>>doc:xwiki:Glossary.Statistical data and metadata exchange.WebHome]]-CSV - The CSV data and [[reference metadata>>doc:xwiki:Glossary.Reference metadata.WebHome]] messages are not backwardly compatible with those under (% style="color:#2ecc71" %)version(%%) 2.1 due to changes to the structure of the messages needed to support new features such as the improved REST API data queries.
--* [[SDMX-EDI>>doc:xwiki:Glossary.SDMX-EDI.WebHome]] – Deprecation of the EDI transmission format means that existing systems designed to send or receive structures or data in EDI will not work with (% style="color:#2ecc71" %)version(%%) 3.0 registries.
--* Information Model – Several structures have been changed in the (% style="color:#2ecc71" %)version(%%) 3.0 model and three removed. For these reasons the (% style="color:#2ecc71" %)version(%%) 3.0 model is not directly compatible with (% style="color:#2ecc71" %)version(%%) 2.1 or earlier, although conversion of specific [[artefacts>>doc:xwiki:Glossary.Artefact.WebHome]] is possible under some circumstances. Loss of information during the conversion process however means that in cases like structure mapping, the conversion is not reversible i.e. it is not possible to recreate the 2.1 structure once it has been converted to the 3.0 model.
++* SOAP API – Deprecation of the SOAP API means that existing systems designed to use SOAP will not work with version 3.0 registries.
++* SDMX-ML – SDMX 2.1 and earlier structure, data and metadata XML messages are not valid in version 3.0. Specifically: legacy data messages including Generic, Compact and Utility are no longer supported. The remaining Structure Specific data message has been changed to support new features such as reporting of reference metadata as part of the dataset, Structure messages have a number of breaking changes, principally modification to the information model, removal of the agency-version-id option for referencing artefacts and changes to the way the structures are organised into ‘collections’ within the message.
++* SDMX-JSON – SDMX 2.1 structure, data and metadata JSON messages are not valid in version 3.0. The data message has been changed to support the improved REST data queries, in particular the ability to retrieve in one operation data from multiple datasets with potentially different Data Structure Definitions. Breaking changes similar to those for the SDMX-ML transmission format have been made to the structure message.
++* SDMX-CSV - The CSV data and reference metadata messages are not backwardly compatible with those under version 2.1 due to changes to the structure of the messages needed to support new features such as the improved REST API data queries.
++* SDMX-EDI – Deprecation of the EDI transmission format means that existing systems designed to send or receive structures or data in EDI will not work with version 3.0 registries.
++* Information Model – Several structures have been changed in the version 3.0 model and three removed. For these reasons the version 3.0 model is not directly compatible with version 2.1 or earlier, although conversion of specific artefacts is possible under some circumstances. Loss of information during the conversion process however means that in cases like structure mapping, the conversion is not reversible i.e. it is not possible to recreate the 2.1 structure once it has been converted to the 3.0 model.
--The [[SDMX>>doc:xwiki:Glossary.Statistical data and metadata exchange.WebHome]] 3.0 Major Changes document provides more information including an analysis of the breaking changes.
++The SDMX 3.0 Major Changes document provides more information including an analysis of the breaking changes.
  = 3 Processes and Business Scope =
  == 3.1 Process Patterns ==
--[[SDMX>>doc:xwiki:Glossary.Statistical data and metadata exchange.WebHome]] identifies three basic process patterns regarding the exchange of statistical data and metadata. These can be described as follows:
++SDMX identifies three basic process patterns regarding the exchange of statistical data and metadata. These can be described as follows:
 . //Bilateral exchange~:// All aspects of the exchange process are agreed between counterparties, including the mechanism for exchange of data and metadata, the formats, the frequency or schedule, and the mode used for communications regarding the exchange. This is perhaps the most common process pattern.
 . //Gateway exchange~:// Gateway exchanges are an organized set of bilateral exchanges, in which several data and metadata collecting organizations or individuals agree to exchange the collected information with each other in a single, known format, and according to a single, known process. This pattern has the effect of reducing the burden of managing multiple bilateral exchanges (in data and metadata collection) across the sharing organizations/individuals. This is also a very common process pattern in the statistical area, where communities of institutions agree on ways to gain efficiencies within the scope of their collective responsibilities.
 . //Data-sharing exchange~:// Open, freely available data formats and process patterns are known and standard. Thus, any organization or individual can use any counterparty’s data and metadata (assuming they are permitted access to it). This model requires no bilateral agreement, but only requires that data and metadata providers and consumers adhere to the standards.
--This document specifies the [[SDMX>>doc:xwiki:Glossary.Statistical data and metadata exchange.WebHome]] standards designed to facilitate exchanges based on any of these process patterns, and shows how [[SDMX>>doc:xwiki:Glossary.Statistical data and metadata exchange.WebHome]] offers advantages in all cases. It is possible to agree bilaterally to use a standard format (such as [[SDMX-ML>>doc:xwiki:Glossary.SDMX-ML.WebHome]] or [[SDMX-JSON>>doc:xwiki:Glossary.SDMX-JSON.WebHome]]); it is possible for data senders in a gateway process to use a standard format for data exchange with each other, or with any [[data providers>>doc:xwiki:Glossary.Data provider.WebHome]] who agree to do so; it is possible to agree to use the full set of [[SDMX>>doc:xwiki:Glossary.Statistical data and metadata exchange.WebHome]] standards to support a common data-sharing process of exchange, whether based on an [[SDMX>>doc:xwiki:Glossary.Statistical data and metadata exchange.WebHome]]-conformant registry or some other architecture.
++This document specifies the SDMX standards designed to facilitate exchanges based on any of these process patterns, and shows how SDMX offers advantages in all cases. It is possible to agree bilaterally to use a standard format (such as SDMX-ML or SDMX-JSON); it is possible for data senders in a gateway process to use a standard format for data exchange with each other, or with any data providers who agree to do so; it is possible to agree to use the full set of SDMX standards to support a common data-sharing process of exchange, whether based on an SDMX-conformant registry or some other architecture.
--The standards specified here specifically support a data-sharing process based on the use of central registry services. Registry services provide visibility into the data and metadata existing within the community, and support the access and use of this data and metadata by providing a set of triggers for automated processing. The data or metadata itself is not stored in a central registry – these services merely provide a useful set of metadata about the data (and additional metadata) in a known location, so that users/applications can easily locate and obtain whatever data and/or metadata is registered. The use of standards for all data, metadata, and the registry services themselves is ubiquitous, permitting a high (% style="color:#2ecc71" %)level(%%) of automation within a data-sharing community.
++The standards specified here specifically support a data-sharing process based on the use of central registry services. Registry services provide visibility into the data and metadata existing within the community, and support the access and use of this data and metadata by providing a set of triggers for automated processing. The data or metadata itself is not stored in a central registry – these services merely provide a useful set of metadata about the data (and additional metadata) in a known location, so that users/applications can easily locate and obtain whatever data and/or metadata is registered. The use of standards for all data, metadata, and the registry services themselves is ubiquitous, permitting a high level of automation within a data-sharing community.
--It should be pointed out that these different process models are not mutually exclusive – a single system capable of expressing data and metadata in [[SDMX>>doc:xwiki:Glossary.Statistical data and metadata exchange.WebHome]]-conformant formats could support all three scenarios. Different standards may be applicable to different processes (for example, many registry services interfaces are used only in a data-sharing scenario) but all have a common basis in a shared information model.
++It should be pointed out that these different process models are not mutually exclusive – a single system capable of expressing data and metadata in SDMX-conformant formats could support all three scenarios. Different standards may be applicable to different processes (for example, many registry services interfaces are used only in a data-sharing scenario) but all have a common basis in a shared information model.
--In addition to looking at collection and reporting, it is also important to consider the dissemination of data. Data and metadata – no matter how they are exchanged between counterparties in the process of their development and creation – are all eventually supplied to an end user of some type. Often, this is through specific applications inside of institutions. But more and more frequently, data and metadata are also published on websites in various formats. The dissemination of data and its accompanying metadata on the web is a focus of the [[SDMX>>doc:xwiki:Glossary.Statistical data and metadata exchange.WebHome]] standards. Standards for statistical data and metadata allow improvements in the publication of data – it becomes more easily possible to process a standard format once the data is obtained, and the data and metadata are linked together, making the comprehension and further processing of the data easier.
++In addition to looking at collection and reporting, it is also important to consider the dissemination of data. Data and metadata – no matter how they are exchanged between counterparties in the process of their development and creation – are all eventually supplied to an end user of some type. Often, this is through specific applications inside of institutions. But more and more frequently, data and metadata are also published on websites in various formats. The dissemination of data and its accompanying metadata on the web is a focus of the SDMX standards. Standards for statistical data and metadata allow improvements in the publication of data – it becomes more easily possible to process a standard format once the data is obtained, and the data and metadata are linked together, making the comprehension and further processing of the data easier.
--In discussions of statistical data, there are many aspects of its dissemination which impact data quality: data discovery, ease of use, and [[timeliness>>doc:xwiki:Glossary.Timeliness.WebHome]]. [[SDMX>>doc:xwiki:Glossary.Statistical data and metadata exchange.WebHome]] standards provide support for all of these aspects of data dissemination. Standard data formats promote ease of use, and provide links to relevant metadata. The (% style="color:#2ecc71" %)concept(%%) of registry services means that data and metadata can more easily be discovered. [[Timeliness>>doc:xwiki:Glossary.Timeliness.WebHome]] is improved throughout the data lifecycle by increases in efficiency, promoted through the availability of metadata and ease of use.
++In discussions of statistical data, there are many aspects of its dissemination which impact data quality: data discovery, ease of use, and timeliness. SDMX standards provide support for all of these aspects of data dissemination. Standard data formats promote ease of use, and provide links to relevant metadata. The concept of registry services means that data and metadata can more easily be discovered. Timeliness is improved throughout the data lifecycle by increases in efficiency, promoted through the availability of metadata and ease of use.
--It is important to note that [[SDMX>>doc:xwiki:Glossary.Statistical data and metadata exchange.WebHome]] is primarily focused on the //exchange// and //dissemination// of statistical data and metadata. There may also be many uses for the standard model and formats specified here in the context of internal processing of data that are not concerned with the exchange between organizations and users, however. It is felt that a clear, standard formatting of data and metadata for the purposes of exchange and dissemination can also facilitate internal processing by organizations and users, but this is not the focus of the specification.
++It is important to note that SDMX is primarily focused on the //exchange// and //dissemination// of statistical data and metadata. There may also be many uses for the standard model and formats specified here in the context of internal processing of data that are not concerned with the exchange between organizations and users, however. It is felt that a clear, standard formatting of data and metadata for the purposes of exchange and dissemination can also facilitate internal processing by organizations and users, but this is not the focus of the specification.
  == 3.2 SDMX and Process Automation ==
--Statistical data and metadata exchanges employ many different automated processes, but some are of more general interest than others. There are some common information technologies that are nearly ubiquitous within information systems today. [[SDMX>>doc:xwiki:Glossary.Statistical data and metadata exchange.WebHome]] aims to provide standards that are most useful for these automated processes and technologies.
++Statistical data and metadata exchanges employ many different automated processes, but some are of more general interest than others. There are some common information technologies that are nearly ubiquitous within information systems today. SDMX aims to provide standards that are most useful for these automated processes and technologies.
  Briefly, these can be described as:
@@ -181,29 +181,29 @@
 . //Presentation and Transformation of Data~:// In order to make data and metadata useful to consumers, they must support automated processes that transform them into application-specific processing formats, other standard formats, and presentational formats. Although not strictly an aspect of exchange, this type of automated processing represents a set of requirements that must be supported if the information exchange between counterparties is itself to be supported.
--The [[SDMX>>doc:xwiki:Glossary.Statistical data and metadata exchange.WebHome]] standards specified here are designed to support the requirements of all of these automation processes and technologies.
++The SDMX standards specified here are designed to support the requirements of all of these automation processes and technologies.
  == 3.3 Statistical Data and Metadata ==
--To avoid confusion about which "data" and "metadata" are the intended content of the [[SDMX>>doc:xwiki:Glossary.Statistical data and metadata exchange.WebHome]] formats specified here, a statement of scope is offered. Statistical "data" are sets of often numeric observations which typically have time associated with them. They are associated with a set of metadata values, representing specific (% style="color:#2ecc71" %)concepts(%%), which act as identifiers and descriptors of the data. These metadata values and (% style="color:#2ecc71" %)concepts(%%) can be understood as the named [[dimensions>>doc:xwiki:Glossary.Dimension.WebHome]] of a multi-dimensional co-ordinate system, describing what is often called a "cube" of data.
++To avoid confusion about which "data" and "metadata" are the intended content of the SDMX formats specified here, a statement of scope is offered. Statistical "data" are sets of often numeric observations which typically have time associated with them. They are associated with a set of metadata values, representing specific concepts, which act as identifiers and descriptors of the data. These metadata values and concepts can be understood as the named dimensions of a multi-dimensional co-ordinate system, describing what is often called a "cube" of data.
--[[SDMX>>doc:xwiki:Glossary.Statistical data and metadata exchange.WebHome]] identifies a standard technique for modelling, expressing, and understanding the structure of this multi-dimensional "cube", allowing automated processing of data from a variety of sources. This approach is widely applicable across types of data and attempts to provide the simplest and most easily comprehensible technique that will support the exchange of this broad set of data and related metadata.
++SDMX identifies a standard technique for modelling, expressing, and understanding the structure of this multi-dimensional "cube", allowing automated processing of data from a variety of sources. This approach is widely applicable across types of data and attempts to provide the simplest and most easily comprehensible technique that will support the exchange of this broad set of data and related metadata.
--The term "metadata" is very broad indeed. A distinction can be made between “structural” metadata – those (% style="color:#2ecc71" %)concepts(%%) used in the description and identification of statistical data and metadata – and “reference” metadata – the larger set of (% style="color:#2ecc71" %)concepts(%%) that describe and qualify statistical [[data sets>>doc:xwiki:Glossary.Data set.WebHome]] and processing more generally, and which are often associated not with specific observations or series of data, but with entire collections of data or even the institutions which provide that data.
++The term "metadata" is very broad indeed. A distinction can be made between “structural” metadata – those concepts used in the description and identification of statistical data and metadata – and “reference” metadata – the larger set of concepts that describe and qualify statistical data sets and processing more generally, and which are often associated not with specific observations or series of data, but with entire collections of data or even the institutions which provide that data.
--The [[SDMX Information Model>>doc:xwiki:Glossary.SDMX Information Model.WebHome]] provides for the structuring not only of data, but also of “reference” metadata. While these [[reference metadata>>doc:xwiki:Glossary.Reference metadata.WebHome]] structures exist independent of the data and its [[structural metadata>>doc:xwiki:Glossary.Structural metadata.WebHome]], they are often linked. The [[SDMX Information Model>>doc:xwiki:Glossary.SDMX Information Model.WebHome]] provides for the attachment of [[reference metadata>>doc:xwiki:Glossary.Reference metadata.WebHome]] to any part of the data or [[structural metadata>>doc:xwiki:Glossary.Structural metadata.WebHome]], as well as for the reporting and exchange of the [[reference metadata>>doc:xwiki:Glossary.Reference metadata.WebHome]] and its structural descriptions. This function of the [[SDMX>>doc:xwiki:Glossary.Statistical data and metadata exchange.WebHome]] standards supports many aspects of data quality initiatives, allowing as it does for the exchange of metadata in its broadest sense, of which quality-related metadata is a major part.
++The SDMX Information Model provides for the structuring not only of data, but also of “reference” metadata. While these reference metadata structures exist independent of the data and its structural metadata, they are often linked. The SDMX Information Model provides for the attachment of reference metadata to any part of the data or structural metadata, as well as for the reporting and exchange of the reference metadata and its structural descriptions. This function of the SDMX standards supports many aspects of data quality initiatives, allowing as it does for the exchange of metadata in its broadest sense, of which quality-related metadata is a major part.
--Metadata are associated not only with data, but also with the process of providing and managing the flow of data. The [[SDMX Information Model>>doc:xwiki:Glossary.SDMX Information Model.WebHome]] provides for a set of metadata concerned with “data provisioning” – metadata which are useful to those who need to understand the content and form of a [[data provider>>doc:xwiki:Glossary.Data provider.WebHome]]’s output. Each [[data provider>>doc:xwiki:Glossary.Data provider.WebHome]] can describe in standard fashion the content of and dependencies within the data and [[metadata sets>>doc:xwiki:Glossary.Metadata set.WebHome]] which they produce, and supply information about the scheduling and mechanism by which their data and metadata are provided. This allows for automation of some validation and control functions, as well as supporting management of data reporting.
++Metadata are associated not only with data, but also with the process of providing and managing the flow of data. The SDMX Information Model provides for a set of metadata concerned with “data provisioning” – metadata which are useful to those who need to understand the content and form of a data provider’s output. Each data provider can describe in standard fashion the content of and dependencies within the data and metadata sets which they produce, and supply information about the scheduling and mechanism by which their data and metadata are provided. This allows for automation of some validation and control functions, as well as supporting management of data reporting.
--[[SDMX>>doc:xwiki:Glossary.Statistical data and metadata exchange.WebHome]] also recognizes the importance of classification schemes in organizing and managing the exchange and dissemination of data and metadata. It is possible to express information about classification schemes and domain [[categories>>doc:xwiki:Glossary.Category.WebHome]] in [[SDMX>>doc:xwiki:Glossary.Statistical data and metadata exchange.WebHome]], along with their relationships to data and [[metadata sets>>doc:xwiki:Glossary.Metadata set.WebHome]], as well as to categorize other objects in the model.
++SDMX also recognizes the importance of classification schemes in organizing and managing the exchange and dissemination of data and metadata. It is possible to express information about classification schemes and domain categories in SDMX, along with their relationships to data and metadata sets, as well as to categorize other objects in the model.
--The [[SDMX>>doc:xwiki:Glossary.Statistical data and metadata exchange.WebHome]] standards offer a common model, a choice of syntax and, for XML, a choice of data formats which support the exchange of any type of statistical data meeting the definition above; several optimized formats are specified based on the specific requirements of each implementation, as described below in the [[SDMX-ML>>doc:xwiki:Glossary.SDMX-ML.WebHome]] section.
++The SDMX standards offer a common model, a choice of syntax and, for XML, a choice of data formats which support the exchange of any type of statistical data meeting the definition above; several optimized formats are specified based on the specific requirements of each implementation, as described below in the SDMX-ML section.
  The formal objects in the information model are presented schematically in Figure 1, and are discussed in more detail elsewhere in this document.
  [[image:SDMX 3-0-0 SECTION 1 FINAL-1.0_en_a3e7967f.png||height="921" width="629"]]
--**Figure 1: High Level Schematic of Major Artefacts in the SDMX 3.0 Information Model**
++Figure 1: High Level Schematic of Major Artefacts in the SDMX 3.0 Information Model
  == 3.4 The SDMX View of Statistical Exchange ==
@@ -280,8 +280,10 @@
  SDMX provides a way of modelling statistical data, and defines the set of metadata constructs used for this purpose. Because SDMX specifies a number of transmission formats for expressing data and structural metadata, the model is used as a mechanism for guaranteeing that transformation between the different formats is lossless. In this sense, all of the formats are syntax-bound expressions of the common information model.
--SDMX recognizes that statistical data is structured; in SDMX this structure is termed a Data Structure Definition. “Data sets” are made up of one or more lower-level “groups”, based on their degrees of similarity. Each group is in turn comprised of one or more “series” of data. Each series or section has a “key” - values for each of a cluster of concepts, also called "dimensions" - which identifies it, and one or more “observations”, which typically combine the time of the observation, and the value of the observation (e.g., measurement). Additionally, metadata may be attached at any level of this structure as descriptive “attributes”. Code lists (enumerations) and other patterns for representation of data and metadata are also modelled.
++SDMX recognizes that statistical data is structured; in SDMX this structure is termed a Data Structure Definition. “Data sets” are made up of one or more lower-level “groups”, based on their degrees of similarity. Each group is in turn comprised of one or more “series” of data. Each series or section has a “key” - values for each of a cluster of concepts, also called
++"dimensions" - which identifies it, and one or more “observations”, which typically combine the time of the observation, and the value of the observation (e.g., measurement). Additionally, metadata may be attached at any level of this structure as descriptive “attributes”. Code lists (enumerations) and other patterns for representation of data and metadata are also modelled.
++
  There is some similarity between “cube” structures commonly used to process statistical data, and the Data Structure Definition idea in the SDMX Information Model. It is important to note that the data as structured according to the SDMX Information Model is optimized for exchange, potentially with partners who may have no ability to process a “cube” of data coming from complex statistical systems. SDMX time series can be understood as “slices” of the cube. Such a slice is identified by its key. A "series" key consists of the values for all dimensions specified by the key family except time. Thus, it is possible to reconstruct and describe data cubes from SDMX-structured data, and to exchange such databases using the interfaces and formats provided for that purpose in the standard. Additional objects such as hierarchical code lists, constraints and structure maps make it possible to more fully model the structure of cubes.
  The information model also provides a view of reference metadata: a mechanism for referencing the meaningful “objects” within the SDMX view of statistical exchange processes (data providers, structures, provisioning agreements, dataflows, metadata flows, etc.) to which metadata is attached; a mechanism for describing a set of meaningful concepts, of organizing them into a presentational structure, and of indicating how their values are represented. This is based on a simple, hierarchical view of reference metadata which is common to many metadata systems and classification/categorization schemes. SDMX provides a model (and XML and JSON formats) for both describing reference metadata structures, and of reporting reference metadata according to those structures.