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1 {{box title="**Contents**"}}
2 {{toc/}}
3 {{/box}}
4
5 **Revision History**
6
7 (% style="width:738.039px" %)
8 |(% style="width:187px" %)Revision|(% style="width:157px" %)Date|(% style="width:390px" %)Contents
9 |(% style="width:187px" %)DRAFT 1.0|(% style="width:157px" %)May 2021|(% style="width:390px" %)Draft release updated for SDMX 3.0 for public consultation
10 |(% style="width:187px" %)1.0|(% style="width:157px" %)October 2021|(% style="width:390px" %)Public Release for SDMX 3.0
11
12 = 1 Overview =
13
14 SDMX version 3.0 introduces new features, improvements and changes to the Standard in the following key areas:
15
16 **Information Model**
17
18 * Simplification and improvement of the reference metadata model
19 * Support for microdata
20 * Support for geospatial data
21 * Support for code list extension and discriminated union of code lists
22 * Improvements to structure mapping
23 * Improvements to code hierarchies for data discovery
24 * Improvements to constraints
25
26 **Versioning of Structural Metadata Artefacts**
27
28 * Adoption of the three-number semantic versioning standard for structural metadata artefacts ([[https:~~/~~/semver.org/>>https://semver.org/||rel="noopener noreferrer" target="_blank"]])
29
30 **REST Web Services Application Programming Interface (API)**
31
32 * Change to a single ‘structure’ resource for structure queries simplifying the REST API specification by reducing the number of resources to five
33 * Improvements to data queries
34 * Improvements to reference metadata queries
35 * Support for structural metadata maintenance using HTTP PUT, POST and DELETE verbs
36
37 **SOAP Web Services API**
38
39 * The SOAP web services API has been deprecated with version 3.0 standardising on REST**;**
40
41 **XML, JSON, CSV and EDI Transmission formats**
42
43 * 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
44 * 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
45 * The SDMX-EDI transmission format for structures and data has been deprecated
46 * The organisation of structures into ‘collections’ in SDMX-ML and SDMX-JSON structure messages has been flattened and simplified
47 * 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
48
49 **Breaking Changes**
50
51 Many of the changes made are ‘breaking’ meaning that, while conversion between versions may be possible in certain circumstances, the 3.0 specification is not directly backwardly compatible with earlier versions of the Standard.
52
53 A summary of the main breaking changes is given in chapter 2.
54
55 **Content of the Document**
56
57 The remainder of the document provides a summary of the main changes. More detailed information can be found the SDMX 3.0 Technical Specifications, in particular:
58
59 * Section 2 – Information Model
60 * Section 5 – Registry Specification
61 * Section 6 – Technical Notes
62 * SDMX-TWG GitHub for the REST API and the XML, JSON and CSV formats
63
64 = 2 Summary of Breaking Changes in 3.0 =
65
66 Version 3.0 introduces breaking changes into the web services API, transmission formats and information model. A summary is given in the table below.
67
68 == //2.1 Web Services API// ==
69
70 (% style="width:948.039px" %)
71 |**REST API**|(% style="width:818px" %)(((
72 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:
73
74 * Structure queries
75 * Data queries
76 * Metadata queries
77 * Availability queries
78
79 Schema queries are backwardly compatible.
80
81 //Guidance for implementors//
82
83 REST API implementors may provide partial backward compatibility by using web server URL rewriting rules to translate version 2.1 structure queries to the 3.0 equivalent.
84
85 Implementors are also recommended to version their API services providing users with an explicit choice of which version to use.
86 )))
87 |**SOAP API**|(% style="width:818px" %)The SOAP API has been deprecated.
88
89 == //2.2 Transmission Formats// ==
90
91 (((
92 (% style="width:952.039px" %)
93 |(% style="width:130px" %)**SDMX-ML**|(% style="width:820px" %)(((
94 The following legacy XML data messages have been deprecated:
95
96 SDMX-ML 1.0/2.0 Generic (time-series) data message
97
98 SDMX-ML 1.0/2.0 Compact (time-series) data message
99
100 SDMX-ML 1.0/2.0 Utility (time-series) data message
101
102 SDMX-ML 1.0/2.0 Cross-Sectional data message SDMX-ML 2.1 Generic data messages (for observations, time-series and cross-sectional data)
103
104 Structure Specific is the only data message option in version 3.0 but is not backwardly compatible with version 2.1 due to several changes including deprecation of the option to reference structures like the DSD, Dataflow and Provision Agreement using their Agency, ID and Version. The time series variant of the message has also been deprecated.
105
106 The SDMX-ML structure message is not backwardly compatible primarily due to:
107
108 * Changes to the information model
109 * Changes to the way the structures are organised into ‘collections’ within the message
110 * Deprecation of the Agency, ID, Version option for referencing of structures in messages
111 )))
112 |(% style="width:130px" %)**SDMX-JSON**|(% style="width:820px" %)(((
113 The JSON data message is not backwardly compatible with version 2.1 primarily due to changes needed to support the improved REST API data queries, in particular the ability to retrieve in one operation data from multiple datasets with potentially different Data Structure Definitions.
114
115 The JSON structure message is not backwardly compatible primarily due to:
116
117 * Changes to the information model
118 * Changes to the way the structures are organised into ‘collections’ within the message
119 * Deprecation of the Agency, ID, Version option for referencing of structures in messages
120 )))
121 |(% style="width:130px" %)**SDMX-EDI**|(% style="width:820px" %)The EDI format for both structures and data has been deprecated.
122 |(% style="width:130px" %)**SDMX-CSV**|(% style="width:820px" %)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.
123 )))
124
125 == //2.3 Information Model// ==
126
127 (((
128 (% style="width:955.039px" %)
129 |(% style="width:132px" %)**Data Structure Definition**|(% style="width:819px" %)(((
130 The version 3.0 Data Structure Definition (DSD) model is not directly backwardly compatible with 2.1 primarily due to the deprecation of the special MeasureDimension.
131
132 //Conversion guidance for implementors//
133
134 Version 2.1 DSDs can be converted to the 3.0 model by creating a measure with the “MEASURE” concept role applied as described in paragraph 3.5.
135
136 Version 3.0 DSDs cannot be reliably converted to the 2.1 model due to the introduction of new features such as multiple measures and value arrays for measures and attributes.
137 )))
138 |(% style="width:132px" %)**Structure mapping model**|(% style="width:819px" %)(((
139 The structure mapping model has changed significantly in version 3.0 with deprecation of the Structure Set maintainable artefact and introduction of five new ones: Representation Map and four variants of item scheme map.
140
141 //Conversion guidance for implementors//
142
143 Version 2.1 structure sets can be practically converted to the version 3.0 structure mapping model.
144
145 Conversion from the version 3.0 structure mapping model to 2.1 is generally possible. However, when attempting to convert mapping rules from 2.1 to 3.0 and back to 2.1, the resulting Structure Set will not be precisely the same as the original. In converting to version 3.0, the system must generate IDs for each of the new maintainable artefacts, but details of the original Structure Set artefacts are lost.
146 )))
147 |(% style="width:132px" %)**Reference metadata model**|(% style="width:819px" %)(((
148 The reference metadata model has changed in version 3.0 with modifications to the role of the Data Structure Definition, Metadata Structure Definition and Metadataflow artefacts. Metadata Provision Agreement and Metadata Provider Scheme have been added. Metadatasets are now identifiable.
149
150 Version 2.1 reference metadata models are not valid in version 3.0.
151
152 //Conversion guidance for implementors//
153
154 A version 2.1 Metadata Structure Definition can be converted to the version 3.0 model under some circumstances, but target information is either lost or has to be translated into a metadataflow. Further, conversion of a Data Structure Definition for collecting reference metadata against a dataset would need to make changes to the dataset’s Data Structure Definition. As the Data Structure Definition may not actually be specified, judgement would need to be taken, perhaps determining the most likely candidate by examining which already have metadata reported against their datasets. A 2.1 metadata report could be converted to a version 3.0 Metadataset if it is attached to a structure, but requires a Metadata Provision Agreement which would need to be created if not already in existence.
155
156 Conversion from the version 3.0 model to version 2.1 cannot be performed reliably. The process would need target information to be derived from analysis of the Metadataflows and Metadata Provision Agreements. Depending on the complexity it may not be possible to express that information in a version 2.1 Data Structure Definition.
157 )))
158 |(% style="width:132px" %)**Constraint model**|(% style="width:819px" %)(((
159 The version 2.1 Content Constraint artefact has been deprecated in version 3.0 and replaced by the Data Constraint for data, and the Metadata Constraint for reference metadata.
160
161 //Conversion guidance for implementors//
162
163 2.1 Content Constraints can be converted without loss to the equivalent version 3.0 Data Constraint model.
164
165 Conversion from 3.0 to 2.1 presents challenges where wildcards have been used, in those cases requiring expansion of the wildcard into explicit values.
166 )))
167 |(% style="width:132px" %)**Hierarchical codelist structures**|(% style="width:819px" %)(((
168 The version 2.1 Hierarchical Codelist artefact has been deprecated in version 3.0 and replaced by two new artefacts, Hierarchy and Hierarchy Association.
169
170 //Conversion guidance for implementors//
171
172 Version 2.1 Hierarchical Codelists can be successfully converted to the version 3.0 hierarchy model. Information on which artefacts to link the hierarchies to on what context would need to be added as a separate procedure.
173
174 Conversion from the version 3.0 model to version 2.1 is possible, but with loss of the linking information
175 )))
176 )))
177
178 = 3 Information Model =
179
180 == //3.1 Version 3.0 Information Model// ==
181
182 [[image:SDMX 3-0-0 Major Changes FINAL-1.0_en_6fc573fe.png||height="404" width="718"]]
183
184 //Figure 1 Version 3.0 simplified Information Model UML class diagram with ‘heat map’ illustrating the areas with most change//
185
186 The schematic above is a simplified UML class diagram of the SDMX 3.0 information model illustrating the major areas of change as a ‘heat map’. Darker colours indicate where new structures have been added in version 3.0 or where structures have been significantly changed.
187
188 A number of ancillary structures including organisation schemes, process and reporting taxonomy are unchanged and have not been shown. Similarly, Organisation Scheme Map and Reporting Taxonomy Map have been omitted for simplicity. A schematic of the 2.1 model is given in Appendix A for comparison purposes.
189
190 == //3.2 Key Changes from Version 2.1// ==
191
192 New Maintainable Artefacts
193
194 * Structure Map
195 * Representation Map
196 * Organisation Scheme Map
197 * Concept Scheme Map
198 * Category Scheme Map
199 * Reporting Taxonomy Map
200 * Value List
201 * Hierarchy
202 * Hierarchy Association
203 * Metadata Constraint
204 * Data Constraint
205 * Metadata Provision Agreement
206 * Metadata Provider Scheme
207 * Metadataset
208
209 New Identifiable Artefacts
210
211 * GeoFeatureSetCode
212 * GeoGridCode
213 * Metadata Provider
214
215 Removed Maintainable Artefacts
216
217 * Structure Set – replaced by Structure Map and the four item scheme maps
218 * Hierarchical Codelist – replaced by Hierarchy and Hierarchy Association • Constraint – replaced by Data Constraint and Metadata Constraint
219
220 Changed Maintainable Artefacts
221
222 * Data Structure Definition – support for microdatasets and reference metadata linked to data
223 * Metadataflow – simplifies exchange of reference metadata, in particular those linked to structures
224 * Metadata Structure Definition – simplified model for reference metadata
225 * Codelist – support for codelist extension and geospatial specialised codelists (GeographicCodelist, GeoGridCodelist)
226 * VTL Mapping Scheme – VTL Concept Mapping Scheme removed to align the VTL / SDMX interface with the 3.0 model
227
228 New Component Representation Types
229
230 * GeospatialInformation – a string type where the value is an expression defining a set of geographical features using a purpose-designed syntax
231
232 == //3.3 Areas Unchanged from Version 2.1// ==
233
234 The following areas of the information model are unchanged from version 2.1:
235
236 * Categories
237 * Concepts
238 * Data providers
239 * Agencies
240 * Data consumers
241 * VTL transformation and expressions – with the exception of VTL mapping scheme as already noted
242 * Reporting taxonomy
243 * Process
244
245 == //3.4 Reference Metadata// ==
246
247 Reference metadata has been substantially re-designed for version 3.0 to simplify the model and better support practical use cases.
248
249 === Simplify Metadata Structure Definition ===
250
251 The Metadata Structure Definition (MSD) has been simplified to remove target information, and the support of multiple report structures. The MSD now only contains Metadata Attributes which are used to define the structure of a report.
252
253 [[image:SDMX 3-0-0 Major Changes FINAL-1.0_en_ad5f5c97.png||height="346" width="494"]]
254
255 //Figure 2 version 2.1 Metadata Structure Definition (MSD)//
256
257 [[image:SDMX 3-0-0 Major Changes FINAL-1.0_en_f2695ed5.png||height="172" width="374"]]
258
259 //Figure 3 the simplified version 3.0 MSD//
260
261 === Change to reference metadata reported against data ===
262
263 Reference metadata associated with datasets, data series or observations are now reported with the data. The dataset’s DSD must reference an MSD to define the structure of its reference metadata. In practice reference metadata for data are transmitted as part of the data message. The metadata attributes are treated in a similar way to the data attributes appearing in the message at the dataset, data series or individual observation level as appropriate. In contrast to simple data attributes, metadata attributes defined by an MSD can be organised into a hierarchical structure as illustrated in Figure 3 above. For this reason, metadata attributes appear in data messages structured in the same way as metadata messages.
264
265 The SDMX-ML example below is an excerpt from a structure specific data message illustrating reporting of reference metadata with a hierarchical structure at the observation level.
266
267 For completeness, the excerpt also shows:
268
269 * OBS_STATUS – a simple observation-level data attribute
270 * TITLE – a multi-lingual data attribute
271 * SOURCE_AGENCY – a multi-value data attribute
272
273 <Obs xsi:type="dsd:ObsType" OBS_VALUE="112" OBS_STAUS=”A” TIME_PERIOD="2010-09">
274
275 <!—- complex multi-value and multi-lingual data attributes ~-~->
276
277 <Comp id="TITLE" xsi:type="ns1:TITLE_ATTRIBUTE">
278
279 <Value>
280
281 <common:Text xml:lang="en">Some English Text</common:Text>
282
283 <common:Text xml:lang="fr">Quelques textes en anglais</common:Text>
284
285 </Value>
286
287 </Comp>
288
289 <Comp id="SOURCE_AGENCY" xsi:type="ns1:SOURCE_AGENCY_ATTRIBUTE">
290
291 <Value>4F0</Value>
292
293 <Value>4D0</Value>
294
295 <Value>CZ2</Value>
296
297 </Comp>
298
299 <!—- metadata attributes are reported like in metadata messages ~-~->
300
301 <Metadata>
302
303 <Attribute id="COLLECTION">
304
305 <Attribute id="METHOD">
306
307 <Text lang="en">AAA</Text>
308
309 </Attribute>
310
311 </Attribute>
312
313 <Attribute id="CONTACT">
314
315 <Value>CONTACT 1</Value>
316
317 <Attribute id="NAME">
318
319 <Value>Contact 1 Name 1</Value>
320
321 </Attribute>
322
323 <Attribute id="NAME">
324
325 <Value>Contact 1 Name 2</Value>
326
327 </Attribute>
328
329 </Attribute>
330
331 <Attribute id="CONTACT">
332
333 <Value>CONTACT 2</Value>
334
335 <Attribute id="NAME">
336
337 <Value>Contact 2 Name 1</Value>
338
339 </Attribute>
340
341 <Attribute id="NAME">
342
343 <Value>Contact 2 Name 2</Value>
344
345 </Attribute>
346
347 </Attribute>
348
349 </Metadata>
350
351 </Obs>
352
353 === New - Metadata Provision Agreement ===
354
355 In version 2.1 a Provision Agreement could be used to report information against a Dataflow or Metadataflow. From version 3.0 this is managed by two separate structures, the Data Provision Agreement and the Metadata Provision Agreement.
356
357 === Move target to Metadataflow and Metadata Provision Agreement ===
358
359 For reference metadata that is reported against structures, the allowable targets information which is used to specify what structures the reference metadata can be reported against, has moved to the Metadataflow and can be further refined in the Metadata Provision Agreement.
360
361 === Add maintainable properties to reference metadata ===
362
363 A Metadataset now has mandatory identification information, (owner id, id, version) enabling metadata providers to uniquely identify their reports for create, update or delete maintenance operations.
364
365 == //3.5 Microdata Exchange// ==
366
367 Several changes have been made the Data Structure Definition to support microdata use cases in addition to aggregated time series.
368
369 === Multiple measures ===
370
371 Multiple measures are a common characteristic of microdatasets. To support this use case, the MeasureDimension has been deprecated and replaced with the option to define zero or more measures. Measures now act like any other component in that they use concepts, can have their own local coded or uncoded representation defined within the
372
373 Data Structure Definition, and can be either mandatory or conditional. Creating a measure with the “MEASURE” concept role applied emulates the version 2.1
374
375 MeasureDimension behaviour as illustrated in the SDMX-ML example below:
376
377 <str:MeasureList id=”MeasureDescriptor”>
378
379 <str:Measure id=”OBS_VALUE” minOccurs=”1” maxOccurs=”1” usage=”mandatory” > <str:ConceptIdentity>
380
381 <Ref id=”OBS_VALUE” maintainableParentID=”CONCEPTS” agencyID=”SDMX” maintainableParentVersion=”1.0.0” />
382
383 </str:ConceptIdentity>
384
385 <str:LocalRepresentation>
386
387 <str:TextFormat textType=”String” isMultiLingual=”true” />
388
389 </str:LocalRepresentation>
390
391 <str:ConceptRole>
392
393 <Ref id=”MEASURE” maintainableParentID=”SDMX_CONCEPT_ROLES” agencyID=”SDMX” maintainableParentVersion=”1.0.0” />
394
395 </str:ConceptRole>
396
397 </str:Measure>
398
399 ...
400
401 <str:Measure>
402
403 </str:MeasureList>
404
405 === Multi-value measures and attributes ===
406
407 Both measures and attributes have been extended with the option to take ‘arrays’ of 193 multiple coded or uncoded values. This supports use cases like multiple observation 194 status flags. New //minOccurs// and //maxOccurs// properties define the valid number of 195 values. The //usage// property separately defines whether the measure or attribute is
408
409 //mandatory// or optional. In the SDMX-ML measure example above, the properties
410
411 //minOccurs=”1” maxOccurs=”1” usage=”mandatory”// specify that OBS_VALUE must be 198 reported, and can only consist of a single value.
412
413 === Attributes relationship to measures ===
414
415 In addition to attaching attributes to a specific level within the dataset, their relationship 202 to measures can also be defined.
416
417 === Value lists ===
418
419 Value lists help in modelling microdata by providing an enumeration similar to code lists 206 but allowing any string values without being restricted to the rules of SDMX identifiers.
420
421 That allows ValueItems (the equivalent to Code) to contain symbols like ‘¥’ and ‘€’, but 208 also means they are not identifiable.
422
423 == //3.6 Geospatial Data Exchange// ==
424
425 The version 3.0 model has been extended to provide explicit support for geospatial data.
426
427 === GeospatialInformation type ===
428
429 A new GeospatialInformation string type has been added which can be used as the 214 representation for any dimension, attribute or measure component. The value which is a 215 string expression conforming to the syntax defined in Section 6 of the technical 216 specifications precisely defines a ‘Geo Feature Set’ – a collection of geographical 217 features like points, lines or polygons. Its use is recommended in conjunction with the “GEO_FEATURE_SET” concept role.
430
431 === Geospatial code lists ===
432
433 Two new specialised types of code list have been added where the definition of each code includes additional geospatial information in addition to the standard ID, name and description:
434
435 * GeographicCodelist – each item includes an element to represent a specific Geo Feature Set which is described using the same expression syntax as for GeospatialInformation type.
436 * GeoGridCodelist – A code list defining a geographical grid composed of cells representing regular squared portions of the Earth. Each item references a cell within the grid.
437
438 === //3.7 Structure Mapping// ===
439
440 The Structure Set in version 2.1 is a container for many mapping structures including Data Structure Map, Codelist Map and Concept Map. For version 3.0 the Structure Set artefact has been deprecated and replaced with a number of new maintainables giving better flexibility and reusability, specifically: Structure Map, Concept Scheme Map, Representation Map, Reporting Taxonomy Map, Category Scheme Map and Organisation Scheme Map.
441
442 The version 2.1 Codelist Map been replaced with Representation Map which allows mappings to be defined between any combination of Code Lists, Value Lists and noncoded representations such as text strings and numbers.
443
444 ==== Many-to-many source and target components ====
445
446 Structure mapping rules may be defined with both multiple source components and multiple target components in contrast to version 2.1 where only one source and target was allowed. That supports many-to-many (n-n) mapping use cases where the output of a mapping rule may be dependent on the combination of a number of input components. For instance:
447
448 Set the output component INDICATOR=”DE_A” if the input components are FREQ=”A” and REF_AREA=”DE”.
449
450 Similarly, an n-n rule may also set the values of any number of output components:
451
452 Set the output components FREQ=”A”, REF_AREA=”DE” if the input component INDICATOR=”DE_A”.
453
454 **Fixed source and target**
455
456 The Structure Map may now define input or output components which have a fixed value.
457
458 ==== Time representations mapping ====
459
460 Non SDMX time representations may now be described in a Structure Map, allowing them to be mapped into SDMX time formats.
461
462 ==== Regular expression and substring mappings ====
463
464 All item maps allow the use of regular expressions and substrings to match source values, specifically: Concept Scheme Map, Reporting Taxonomy Map, Category Scheme Map and Organisation Scheme Map.
465
466 ==== Item maps validity period ====
467
468 Item maps may further define the period for which the mapping is valid, meaning the mapping rule will only be applied if the row of information being mapped is within the period.
469
470 === //3.8 Constraints// ===
471
472 Constraints in version 3.0 are modelled using two separate artefacts which replace the version 2.1 content constraint:
473
474 * data constraint for data; and
475 * metadata constraint for reference metadata.
476
477 Metadata constraint differs from its data counterpart in having a simplified cube region model better suited to reference metadata reporting use cases and not carrying details of the constrained targets – that information instead being defined directly within the metadataflow and Metadata Provision Agreement. Thus, metadata related constraints only specify constraints to the values of metadata attributes.
478
479 The ‘%’ wildcard character can now be used when defining cube region constraints to match multiple codes with a single expression, for instance for economic activity, ISIC4_% matches all codes beginning with ‘ISIC4_’ avoiding the need to maintain an explicit list.
480
481 The validity period definition has been moved from the constraint to the individual constraining terms, specifically CubeRegion, DataKeySet and MetadataTargetRegion providing more granular control.
482
483 Attachment constraints have been deprecated due to a lack of use cases.
484
485 === //3.9 Code List Extension// ===
486
487 In addition to the two new specialised geospatial forms, the option has been added to define a code list as an extension of, or by inheriting codes from, other lists. An optional prefix can be added to inherited codes to disambiguate duplicates.
488
489 This feature allows new code lists to be easily derived from existing lists without the need to make and manually maintain copies. When querying for extended code list structures using the REST API, the option has been added to retrieve either the definition or the materialised list. Traditional literal lists of codes continue to be supported.
490
491 === //3.10 Discriminated Union of Code Lists// ===
492
493 Combining code list extension with wildcarded constraints solves the discriminated union of code lists problem where a classification or breakdown has multiple “variants” which are all valid but mutually exclusive. A common example is economic activity where several alternative classification schemes are in use including ISIC revisions 1 to 4 and NACE as used in the European Community.
494
495 === //3.11 Code Hierarchies// ===
496
497 Code hierarchies allow the definition of complex hierarchies of codes from potentially multiple lists for data discovery purposes. Hierarchical Codelist has been deprecated and replaced by two new artefacts: Hierarchy – the actual hierarchy of codes, and Hierarchy Association links hierarchies directly to any other identifiable object, a capability missing 312 from the version 2.1 model. Further, the linkage can be within a particular context, for instance linking a hierarchy to a dimension within the context of a specific Dataflow (dimension REF_AREA in the context of the ECB:EXR Dataflow).
498
499 = 4 Versioning of Structural Metadata Artefacts =
500
501 Version 3.0 adopts semantic versioning principles for versioning of metadata artefacts following the rules set out at __[[https:~~/~~/semver.org>>https://semver.org]] __However, this is not mandatory, and organisations may continue to use the pre-existing two-digit versioning strategy, or not to version artefacts by omitting the //version// property. The version number no longer defaults to 1.0 if not explicitly set.
502
503 Semantic version numbers are three digits:
504
505 MAJOR.MINOR.PATCH
506
507 Where
508
509 * The first digit (major) indicates that changes (either new features or bug fixes) are not backward compatible.
510 * The second digit (minor) indicates that features have been added in a backward compatible manner.
511 * The third digit (patch) indicates that bugs have been fixed in a backward compatible manner.
512
513 Examples:
514
515 SDMX:CL_AREA(1.0.0)
516
517 SDMX:CL_AREA(2.3.2)
518
519 == Dependency management ==
520
521 Additional constructs are possible for dependency management when referencing structures. For instance:
522
523 2.3+.1 Means the currently latest available version >= “2.3.1” and < “3.0.0” (all backwards compatible versions >= “2.3.1”).
524
525 2+.3.1 Means the currently latest available version >= “2.3.1” (even if not backwards compatible).
526
527 == Draft structures ==
528
529 A key principle is that semantically versioned structures are immutable and must not be changed without a corresponding change to the version number, except where explicitly marked as draft using extensions to the version number.
530
531 MAJOR.MINOR.PATCH-EXTENSION
532
533 1.10.0-draft Means that version 1.10.0 is still being modified and may change – equivalent to setting isFinal=false in SDMX 2.1.
534
535 1.10.0-unstable Alternative to -draft.
536
537 1.10.0-notfinal Alternative to -draft.
538
539 The SDMX 2.1 isFinal property is deprecated in 3.0.
540
541 = 5 REST Web Services API =
542
543 == //5.1 Simplified list of resources// ==
544
545 The version 3.0 REST API has just five main resources:
546
547 * structure
548 * data
549 * schema
550 * availability
551 * metadata
552
553 All structure and item queries have been organised under the structure resource in contrast to the version 2.1 API which specified a separate resource for each structure.
554
555 This and changes in the URLs and query parameters on the data, availability and metadata resources means that, with the exception of schema queries, the version 3.0 API is not backwardly compatible.
556
557 == //5.2 Improved data queries// ==
558
559 Data queries have been changed to provide more granular selections from contexts wider than just a Dataflow.
560
561 === Extend the context of data retrieval ===
562
563 Version 2.1 data queries always retrieved data from a single specific Dataflow. In version 3.0, the query context may be specified as:
564
565 * Dataflow;
566 * Data Structure Definition – i.e., all Dataflows that use it; or
567 * Provision Agreement – i.e., all Dataflows associated with it.
568
569 Data queries may also search across datasets, for instance “retrieve all data about a country”.
570
571 === Component-based filters ===
572
573 Expressions filtering on individual components can now be included as part of the data query URL.
574
575 /data/dataflow/ESTAT/ICP?c[REF_AREA]=CH&c[CONF_STATUS]=F
576
577 === Support for operators ===
578
579 Filter expressions can also include operators.
580
581 /data/dataflow/ESTAT/ICP?c[REF_AREA]=DE&c[ICP_ITEM]=sw:01&c[TIME_PERIOD]=ge:2015 Operators include:
582
583 (% style="width:531.039px" %)
584 |(% style="width:151px" %)eq|(% style="width:378px" %)Equals
585 |(% style="width:151px" %)ne|(% style="width:378px" %)Not equal to
586 |(% style="width:151px" %)le|(% style="width:378px" %)Less than
587 |(% style="width:151px" %)ge|(% style="width:378px" %)Greater than or equal to
588 |(% style="width:151px" %)sw|(% style="width:378px" %)Starts with
589
590 === Support for multiple keys ===
591
592 Queries can now specify multiple series keys.
593
594 /data/dataflow/ESTAT/ICP/1.0.0/M…A.ANR,M…A.INX,M…B.CTG
595
596 == //5.3 Improved reference metadata queries// ==
597
598 Reference metadata queries have been improved with a number of new options to retrieve metadata reports.
599
600 **Get metadata reports by ID**
601
602 /metadata/metadataset/ESTAT/QUALITY_REPORT/1.0.0
603
604 **Get metadata reports by Dataflow**
605
606 /metadata/metadataflow/ECB/METHODOLOGY/*/FR2
607
608 **Get metadata reports about a Data Structure Definition**
609
610 /metadata/structure/datastructure/BIS/BIS_CBS/1.0
611
612 == //5.4 Structural metadata maintenance// ==
613
614 Support has been added for maintenance of structural metadata.
615
616 HTTP verbs PUT, POST and DELETE may be used to submit SDMX-ML or SDMX-JSON structure messages to an SDMX registry for the purposes of adding, updating or deleting structural metadata artefacts.
617
618 = 6 XML, JSON, CSV and EDI Transmission formats =
619
620 == //6.1 SDMX-ML// ==
621
622 The SDMX-ML XML messages have been modified and updated for version 3.0. While they broadly follow the same principles, there have been significant changes which break backward compatibility.
623
624 === Structure message ===
625
626 The SDMX-ML structure message is used for transmission of structural metadata. It closely reflects the SDMX information model and has therefore been significantly updated for version 3.0 with the addition of new structures, modifications where structures have changed, and removal of deprecated structures like Structure Set.
627
628 Additionally, the way the individual artefacts are organised into ‘collections’ within the message has been significantly revised with a simpler flat structure adopted as set out in the following table:
629
630 (% style="width:1102.04px" %)
631 |(% style="width:321px" %)**Artefact type**|(% style="width:351px" %)**Version 2.1 Collection**|(% style="width:426px" %)**Version 3.0 Collection**
632 |(% style="width:321px" %)AgencyScheme|(% style="width:351px" %)OrganisationSchemes|(% style="width:426px" %)AgencySchemes
633 |(% style="width:321px" %)DataConsumerScheme|(% style="width:351px" %)OrganisationSchemes|(% style="width:426px" %)DataConsumerSchemes
634 |(% style="width:321px" %)DataProviderScheme|(% style="width:351px" %)OrganisationSchemes|(% style="width:426px" %)DataProviderSchemes
635 |(% style="width:321px" %)MetadataProviderScheme|(% style="width:351px" %)OrganisationSchemes|(% style="width:426px" %)MetadataProviderSchemes
636 |(% style="width:321px" %)OrganisationUnitScheme|(% style="width:351px" %)OrganisationSchemes|(% style="width:426px" %)OrganisationUnitSchemes
637 |(% style="width:321px" %)GeographicCodelist|(% style="width:351px" %)Codelists|(% style="width:426px" %)GeographicCodelists
638 |(% style="width:321px" %)GeoGridCodelist|(% style="width:351px" %)Codelists|(% style="width:426px" %)GeoGridCodelists
639 |(% style="width:321px" %)ConceptScheme|(% style="width:351px" %)Concepts|(% style="width:426px" %)ConceptSchemes
640 |(% style="width:321px" %)ValueList|(% style="width:351px" %)Codelists|(% style="width:426px" %)ValueLists
641 |(% style="width:321px" %)StructureMap|(% style="width:351px" %)StructureMappings|(% style="width:426px" %)StructureMaps
642 |(% style="width:321px" %)RepresentationMap|(% style="width:351px" %)StructureMappings|(% style="width:426px" %)RepresentationMaps
643 |(% style="width:321px" %)ConceptSchemeMap|(% style="width:351px" %)StructureMappings|(% style="width:426px" %)ConceptSchemeMaps
644 |(% style="width:321px" %)CategorySchemeMap|(% style="width:351px" %)StructureMappings|(% style="width:426px" %)CategorySchemeMaps
645 |(% style="width:321px" %)OrganisationSchemeMap|(% style="width:351px" %)StructureMappings|(% style="width:426px" %)OrganisationSchemeMaps
646 |(% style="width:321px" %)ReportingTaxonomyMap|(% style="width:351px" %)StructureMappings|(% style="width:426px" %)ReportingTaxonomyMaps
647 |(% style="width:321px" %)DataConstraint|(% style="width:351px" %)Constraints|(% style="width:426px" %)DataConstraints
648 |(% style="width:321px" %)MetadataConstraint|(% style="width:351px" %)Constraints|(% style="width:426px" %)MetadataConstraints
649 |(% style="width:321px" %)MetadataProvisionAgreement|(% style="width:351px" %)ProvisionAgreement|(% style="width:426px" %)MetadataProvisionAgreements
650 |(% style="width:321px" %)CustomTypeScheme|(% style="width:351px" %)CustomTypes|(% style="width:426px" %)CustomTypeSchemes
651 |(% style="width:321px" %)VtlMappingScheme|(% style="width:351px" %)VtlMappings|(% style="width:426px" %)VtlMappingSchemes
652 |(% style="width:321px" %)NamePersonalisationScheme|(% style="width:351px" %)NamePersonalisations|(% style="width:426px" %)NamePersonalisationSchemes
653 |(% style="width:321px" %)RulesetScheme|(% style="width:351px" %)Rulesets|(% style="width:426px" %)RulesetSchemes
654 |(% style="width:321px" %)TransformationScheme|(% style="width:351px" %)Transformations|(% style="width:426px" %)TransformationSchemes
655 |(% style="width:321px" %)UserDefinedOperatorScheme|(% style="width:351px" %)UserDefinedOperators|(% style="width:426px" %)UserDefinedOperatorSchemes
656
657 No changes have been made to the way the following artefacts are organised in the structure message:
658
659 (% style="width:1106.04px" %)
660 |(% style="width:326px" %)**Artefact type**|(% style="width:776px" %)**Collection**
661 |(% style="width:326px" %)Dataflow|(% style="width:776px" %)Dataflows
662 |(% style="width:326px" %)Metadataflow|(% style="width:776px" %)Metadataflows
663 |(% style="width:326px" %)CategoryScheme|(% style="width:776px" %)CategorySchemes
664 |(% style="width:326px" %)Categorisation|(% style="width:776px" %)Categorisations
665 |(% style="width:326px" %)Codelist|(% style="width:776px" %)Codelists
666 |(% style="width:326px" %)Hierarchy|(% style="width:776px" %)Hierarchies
667 |(% style="width:326px" %)HierarchyAssociation|(% style="width:776px" %)HierarchyAssociations
668 |(% style="width:326px" %)MetadataStructure|(% style="width:776px" %)MetadataStructures
669 |(% style="width:326px" %)DataStructure|(% style="width:776px" %)DataStructures
670 |(% style="width:326px" %)ReportingTaxonomy|(% style="width:776px" %)ReportingTaxonomies
671 |(% style="width:326px" %)Process|(% style="width:776px" %)Processes
672 |(% style="width:326px" %)ProvisionAgreement|(% style="width:776px" %)ProvisionAgreements
673
674 From version 3.0, collections can appear in any order within a structure message.
675
676 === Data messages ===
677
678 All legacy SDMX-ML data messages have been deprecated with the exception of Structure Specific Data which becomes the sole standard format for transmission of SDMX data in XML in version 3.0.
679
680 Specifically, the following data messages are not supported in version 3.0:
681
682 * SDMX-ML 1.0/2.0 Generic (time-series) data message
683 * SDMX-ML 1.0/2.0 Compact (time-series) data message
684 * SDMX-ML 1.0/2.0 Utility (time-series) data message
685 * SDMX-ML 1.0/2.0 Cross-Sectional data message
686 * SDMX-ML 2.1 Generic data messages (for observations, time-series and crosssectional data)
687
688 The Structure Specific Data message has been extended to support the transmission of microdata sets, in particular those with multiple measures and array values for measures and attributes.
689
690 As detailed in paragraph 3.4, the message now additionally allows data’s reference metadata to be reported as an integral part of the dataset. Like data attributes, these metadata attributes are included in the data message at the dataset, series or observation level as appropriate.
691
692 The time series variant of the Structure Specific Data message is no longer used.
693
694 === Reference metadata message ===
695
696 The Generic Metadata message remains the standard format for transmission of reference metadata sets in XML but has been modified to support the revised version 3.0 reference metadata model.
697
698 === Registry structural metadata ‘query’ messages ===
699
700 As a consequence of the deprecation of the SOAP API and standardisation on REST, the structural metadata ‘query’ messages have all been removed. In version 3.0, querying an SDMX Registry for structural metadata is performed solely using REST GET.
701
702 === Structure referencing ===
703
704 The option to reference structures using Agency, ID and Version has been removed. From SDMX version 3.0 URN is used for all referencing purposes with the exception of local references such as where groups reference dimensions within a DSD.
705
706 == //6.2 SDMX-JSON// ==
707
708 Like SDMX-ML, the SDMX-JSON messages have been significantly modified and updated for version 3.0. They are not backwardly compatible with version 2.1.
709
710 === Structure message ===
711
712 The SDMX-JSON structure message closely replicates the SDMX-ML equivalent. Like that of SDMX-ML it has been updated to align it with the version 3.0 information model with addition, deletion and modification of artefacts as required. The organisation of the structure collections has also been revised as detailed in paragraph 6.1.
713
714 === Data message ===
715
716 The SDMX-JSON data message has similarly be updated. Additional changes have been made to allow a single message to carry data from multiple datasets with potentially different Data Structure Definitions to support REST data queries of the form “retrieve all data about a country”. For this reason, the version 3.0 SDMX-JSON is not backwardly compatible with version 2.1 data messages. Support has been added for the transmission of microdata and reporting of reference metadata on data as an integral part of the dataset.
717
718 === Reference metadata message ===
719
720 The SDMX-JSON metadata message has also been updated to support the version 3.0 reference metadata and Metadataset specifications.
721
722 === Structure referencing ===
723
724 As for SDMX-ML, the option to reference structures using Agency, ID and Version has been removed with URN used for all non-local referencing purposes.
725
726 == //6.3 SDMX-CSV// ==
727
728 CSV in SDMX is used transmission of data and reference metadata only.
729
730 === Data message ===
731
732 The SDMX-CSV data message has been modified to align with the version 3.0 information model, support the enhanced REST API and ensure that data can be freely converted to and from the XML and JSON formats without loss. These changes include:
733
734 * An additional column identifying the type if the artefact defining the structure of the data: “dataflow”, “datastructure” or “dataprovision”; • A column for the structure artefact’s identification of the form
735
736 ESTAT:NA_MAIN(1.6.0) which replaces the dataflow identifier in version 2.1; and
737
738 * A column for the dataset action: information, append, replace or delete, which is consistent with both the the SDMX-ML and SDMX-JSON data messages.
739
740 === Reference metadata message ===
741
742 The SDMX-CSV metadata message is new for version 3.0 and, like the SDMX-ML and SDMX-JSON equivalents, is used for the transmission reference metadata sets.
743
744 === //6.4 EDI deprecation// ===
745
746 The EDI format for transmission of both structures and data has been deprecated. Version 3.0 is therefore not backwardly compatible with legacy EDI messages.
747
748 = Appendix A – Version 2.1 Information Model =
749
750 [[image:SDMX 3-0-0 Major Changes FINAL-1.0_en_5f21cdf9.png||height="319" width="718"]]