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Version 10.1 by Helena on 2025/05/14 13:47
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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
219 * Constraint – replaced by Data Constraint and Metadata Constraint
220
221 Changed Maintainable Artefacts
222
223 * Data Structure Definition – support for microdatasets and reference metadata linked to data
224 * Metadataflow – simplifies exchange of reference metadata, in particular those linked to structures
225 * Metadata Structure Definition – simplified model for reference metadata
226 * Codelist – support for codelist extension and geospatial specialised codelists (GeographicCodelist, GeoGridCodelist)
227 * VTL Mapping Scheme – VTL Concept Mapping Scheme removed to align the VTL / SDMX interface with the 3.0 model
228
229 New Component Representation Types
230
231 * GeospatialInformation – a string type where the value is an expression defining a set of geographical features using a purpose-designed syntax
232
233 == //3.3 Areas Unchanged from Version 2.1// ==
234
235 The following areas of the information model are unchanged from version 2.1:
236
237 * Categories
238 * Concepts
239 * Data providers
240 * Agencies
241 * Data consumers
242 * VTL transformation and expressions – with the exception of VTL mapping scheme as already noted
243 * Reporting taxonomy
244 * Process
245
246 == //3.4 Reference Metadata// ==
247
248 Reference metadata has been substantially re-designed for version 3.0 to simplify the model and better support practical use cases.
249
250 === Simplify Metadata Structure Definition ===
251
252 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.
253
254 [[image:SDMX 3-0-0 Major Changes FINAL-1.0_en_ad5f5c97.png||height="346" width="494"]]
255
256 //Figure 2 version 2.1 Metadata Structure Definition (MSD)//
257
258 [[image:SDMX 3-0-0 Major Changes FINAL-1.0_en_f2695ed5.png||height="172" width="374"]]
259
260 //Figure 3 the simplified version 3.0 MSD//
261
262 === Change to reference metadata reported against data ===
263
264 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.
265
266 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.
267
268 For completeness, the excerpt also shows:
269
270 * OBS_STATUS – a simple observation-level data attribute
271 * TITLE – a multi-lingual data attribute
272 * SOURCE_AGENCY – a multi-value data attribute
273
274 <Obs xsi:type="dsd:ObsType" OBS_VALUE="112" OBS_STAUS=”A” TIME_PERIOD="2010-09">
275
276 <!—- complex multi-value and multi-lingual data attributes ~-~->
277
278 <Comp id="TITLE" xsi:type="ns1:TITLE_ATTRIBUTE">
279
280 <Value>
281
282 <common:Text xml:lang="en">Some English Text</common:Text>
283
284 <common:Text xml:lang="fr">Quelques textes en anglais</common:Text>
285
286 </Value>
287
288 </Comp>
289
290 <Comp id="SOURCE_AGENCY" xsi:type="ns1:SOURCE_AGENCY_ATTRIBUTE">
291
292 <Value>4F0</Value>
293
294 <Value>4D0</Value>
295
296 <Value>CZ2</Value>
297
298 </Comp>
299
300 <!—- metadata attributes are reported like in metadata messages ~-~->
301
302 <Metadata>
303
304 <Attribute id="COLLECTION">
305
306 <Attribute id="METHOD">
307
308 <Text lang="en">AAA</Text>
309
310 </Attribute>
311
312 </Attribute>
313
314 <Attribute id="CONTACT">
315
316 <Value>CONTACT 1</Value>
317
318 <Attribute id="NAME">
319
320 <Value>Contact 1 Name 1</Value>
321
322 </Attribute>
323
324 <Attribute id="NAME">
325
326 <Value>Contact 1 Name 2</Value>
327
328 </Attribute>
329
330 </Attribute>
331
332 <Attribute id="CONTACT">
333
334 <Value>CONTACT 2</Value>
335
336 <Attribute id="NAME">
337
338 <Value>Contact 2 Name 1</Value>
339
340 </Attribute>
341
342 <Attribute id="NAME">
343
344 <Value>Contact 2 Name 2</Value>
345
346 </Attribute>
347
348 </Attribute>
349
350 </Metadata>
351
352 </Obs>
353
354 === New - Metadata Provision Agreement ===
355
356 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.
357
358 === Move target to Metadataflow and Metadata Provision Agreement ===
359
360 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.
361
362 === Add maintainable properties to reference metadata ===
363
364 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.
365
366 == //3.5 Microdata Exchange// ==
367
368 Several changes have been made the Data Structure Definition to support microdata use cases in addition to aggregated time series.
369
370 === Multiple measures ===
371
372 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
373
374 Data Structure Definition, and can be either mandatory or conditional. Creating a measure with the “MEASURE” concept role applied emulates the version 2.1
375
376 MeasureDimension behaviour as illustrated in the SDMX-ML example below:
377
378 <str:MeasureList id=”MeasureDescriptor”>
379
380 <str:Measure id=”OBS_VALUE” minOccurs=”1” maxOccurs=”1” usage=”mandatory” > <str:ConceptIdentity>
381
382 <Ref id=”OBS_VALUE” maintainableParentID=”CONCEPTS” agencyID=”SDMX” maintainableParentVersion=”1.0.0” />
383
384 </str:ConceptIdentity>
385
386 <str:LocalRepresentation>
387
388 <str:TextFormat textType=”String” isMultiLingual=”true” />
389
390 </str:LocalRepresentation>
391
392 <str:ConceptRole>
393
394 <Ref id=”MEASURE” maintainableParentID=”SDMX_CONCEPT_ROLES” agencyID=”SDMX” maintainableParentVersion=”1.0.0” />
395
396 </str:ConceptRole>
397
398 </str:Measure>
399
400 ...
401
402 <str:Measure>
403
404 </str:MeasureList>
405
406 === Multi-value measures and attributes ===
407
408 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
409
410 //mandatory// or optional. In the SDMX-ML measure example above, the properties
411
412 //minOccurs=”1” maxOccurs=”1” usage=”mandatory”// specify that OBS_VALUE must be 198 reported, and can only consist of a single value.
413
414 === Attributes relationship to measures ===
415
416 In addition to attaching attributes to a specific level within the dataset, their relationship 202 to measures can also be defined.
417
418 === Value lists ===
419
420 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.
421
422 That allows ValueItems (the equivalent to Code) to contain symbols like ‘¥’ and ‘€’, but 208 also means they are not identifiable.
423
424 == //3.6 Geospatial Data Exchange// ==
425
426 The version 3.0 model has been extended to provide explicit support for geospatial data.
427
428 === GeospatialInformation type ===
429
430 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.
431
432 === Geospatial code lists ===
433
434 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:
435
436 * 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.
437 * 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.
438
439 === //3.7 Structure Mapping// ===
440
441 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.
442
443 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.
444
445 ==== Many-to-many source and target components ====
446
447 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:
448
449 Set the output component INDICATOR=”DE_A” if the input components are FREQ=”A” and REF_AREA=”DE”.
450
451 Similarly, an n-n rule may also set the values of any number of output components:
452
453 Set the output components FREQ=”A”, REF_AREA=”DE” if the input component INDICATOR=”DE_A”.
454
455 **Fixed source and target**
456
457 The Structure Map may now define input or output components which have a fixed value.
458
459 ==== Time representations mapping ====
460
461 Non SDMX time representations may now be described in a Structure Map, allowing them to be mapped into SDMX time formats.
462
463 ==== Regular expression and substring mappings ====
464
465 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.
466
467 ==== Item maps validity period ====
468
469 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.
470
471 === //3.8 Constraints// ===
472
473 Constraints in version 3.0 are modelled using two separate artefacts which replace the version 2.1 content constraint:
474
475 * data constraint for data; and
476 * metadata constraint for reference metadata.
477
478 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.
479
480 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.
481
482 The validity period definition has been moved from the constraint to the individual constraining terms, specifically CubeRegion, DataKeySet and MetadataTargetRegion providing more granular control.
483
484 Attachment constraints have been deprecated due to a lack of use cases.
485
486 === //3.9 Code List Extension// ===
487
488 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.
489
490 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.
491
492 === //3.10 Discriminated Union of Code Lists// ===
493
494 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.
495
496 === //3.11 Code Hierarchies// ===
497
498 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).
499
500 = 4 Versioning of Structural Metadata Artefacts =
501
502 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.
503
504 Semantic version numbers are three digits:
505
506 MAJOR.MINOR.PATCH
507
508 Where
509
510 * The first digit (major) indicates that changes (either new features or bug fixes) are not backward compatible.
511 * The second digit (minor) indicates that features have been added in a backward compatible manner.
512 * The third digit (patch) indicates that bugs have been fixed in a backward compatible manner.
513
514 Examples:
515
516 SDMX:CL_AREA(1.0.0)
517
518 SDMX:CL_AREA(2.3.2)
519
520 == Dependency management ==
521
522 Additional constructs are possible for dependency management when referencing structures. For instance:
523
524 2.3+.1 Means the currently latest available version >= “2.3.1” and < “3.0.0” (all backwards compatible versions >= “2.3.1”).
525
526 2+.3.1 Means the currently latest available version >= “2.3.1” (even if not backwards compatible).
527
528 == Draft structures ==
529
530 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.
531
532 MAJOR.MINOR.PATCH-EXTENSION
533
534 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.
535
536 1.10.0-unstable Alternative to -draft.
537
538 1.10.0-notfinal Alternative to -draft.
539
540 The SDMX 2.1 isFinal property is deprecated in 3.0.
541
542 = 5 REST Web Services API =
543
544 == //5.1 Simplified list of resources// ==
545
546 The version 3.0 REST API has just five main resources:
547
548 * structure
549 * data
550 * schema
551 * availability
552 * metadata
553
554 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.
555
556 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.
557
558 == //5.2 Improved data queries// ==
559
560 Data queries have been changed to provide more granular selections from contexts wider than just a Dataflow.
561
562 === Extend the context of data retrieval ===
563
564 Version 2.1 data queries always retrieved data from a single specific Dataflow. In version 3.0, the query context may be specified as:
565
566 * Dataflow;
567 * Data Structure Definition – i.e., all Dataflows that use it; or
568 * Provision Agreement – i.e., all Dataflows associated with it.
569
570 Data queries may also search across datasets, for instance “retrieve all data about a country”.
571
572 === Component-based filters ===
573
574 Expressions filtering on individual components can now be included as part of the data query URL.
575
576 /data/dataflow/ESTAT/ICP?c[REF_AREA]=CH&c[CONF_STATUS]=F
577
578 === Support for operators ===
579
580 Filter expressions can also include operators.
581
582 /data/dataflow/ESTAT/ICP?c[REF_AREA]=DE&c[ICP_ITEM]=sw:01&c[TIME_PERIOD]=ge:2015 Operators include:
583
584 (% style="width:531.039px" %)
585 |(% style="width:151px" %)eq|(% style="width:378px" %)Equals
586 |(% style="width:151px" %)ne|(% style="width:378px" %)Not equal to
587 |(% style="width:151px" %)le|(% style="width:378px" %)Less than
588 |(% style="width:151px" %)ge|(% style="width:378px" %)Greater than or equal to
589 |(% style="width:151px" %)sw|(% style="width:378px" %)Starts with
590
591 === Support for multiple keys ===
592
593 Queries can now specify multiple series keys.
594
595 /data/dataflow/ESTAT/ICP/1.0.0/M…A.ANR,M…A.INX,M…B.CTG
596
597 == //5.3 Improved reference metadata queries// ==
598
599 Reference metadata queries have been improved with a number of new options to retrieve metadata reports.
600
601 **Get metadata reports by ID**
602
603 /metadata/metadataset/ESTAT/QUALITY_REPORT/1.0.0
604
605 **Get metadata reports by Dataflow**
606
607 /metadata/metadataflow/ECB/METHODOLOGY/*/FR2
608
609 **Get metadata reports about a Data Structure Definition**
610
611 /metadata/structure/datastructure/BIS/BIS_CBS/1.0
612
613 == //5.4 Structural metadata maintenance// ==
614
615 Support has been added for maintenance of structural metadata.
616
617 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.
618
619 = 6 XML, JSON, CSV and EDI Transmission formats =
620
621 == //6.1 SDMX-ML// ==
622
623 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.
624
625 === Structure message ===
626
627 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.
628
629 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:
630
631 (% style="width:1102.04px" %)
632 |(% style="width:321px" %)**Artefact type**|(% style="width:351px" %)**Version 2.1 Collection**|(% style="width:426px" %)**Version 3.0 Collection**
633 |(% style="width:321px" %)AgencyScheme|(% style="width:351px" %)OrganisationSchemes|(% style="width:426px" %)AgencySchemes
634 |(% style="width:321px" %)DataConsumerScheme|(% style="width:351px" %)OrganisationSchemes|(% style="width:426px" %)DataConsumerSchemes
635 |(% style="width:321px" %)DataProviderScheme|(% style="width:351px" %)OrganisationSchemes|(% style="width:426px" %)DataProviderSchemes
636 |(% style="width:321px" %)MetadataProviderScheme|(% style="width:351px" %)OrganisationSchemes|(% style="width:426px" %)MetadataProviderSchemes
637 |(% style="width:321px" %)OrganisationUnitScheme|(% style="width:351px" %)OrganisationSchemes|(% style="width:426px" %)OrganisationUnitSchemes
638 |(% style="width:321px" %)GeographicCodelist|(% style="width:351px" %)Codelists|(% style="width:426px" %)GeographicCodelists
639 |(% style="width:321px" %)GeoGridCodelist|(% style="width:351px" %)Codelists|(% style="width:426px" %)GeoGridCodelists
640 |(% style="width:321px" %)ConceptScheme|(% style="width:351px" %)Concepts|(% style="width:426px" %)ConceptSchemes
641 |(% style="width:321px" %)ValueList|(% style="width:351px" %)Codelists|(% style="width:426px" %)ValueLists
642 |(% style="width:321px" %)StructureMap|(% style="width:351px" %)StructureMappings|(% style="width:426px" %)StructureMaps
643 |(% style="width:321px" %)RepresentationMap|(% style="width:351px" %)StructureMappings|(% style="width:426px" %)RepresentationMaps
644 |(% style="width:321px" %)ConceptSchemeMap|(% style="width:351px" %)StructureMappings|(% style="width:426px" %)ConceptSchemeMaps
645 |(% style="width:321px" %)CategorySchemeMap|(% style="width:351px" %)StructureMappings|(% style="width:426px" %)CategorySchemeMaps
646 |(% style="width:321px" %)OrganisationSchemeMap|(% style="width:351px" %)StructureMappings|(% style="width:426px" %)OrganisationSchemeMaps
647 |(% style="width:321px" %)ReportingTaxonomyMap|(% style="width:351px" %)StructureMappings|(% style="width:426px" %)ReportingTaxonomyMaps
648 |(% style="width:321px" %)DataConstraint|(% style="width:351px" %)Constraints|(% style="width:426px" %)DataConstraints
649 |(% style="width:321px" %)MetadataConstraint|(% style="width:351px" %)Constraints|(% style="width:426px" %)MetadataConstraints
650 |(% style="width:321px" %)MetadataProvisionAgreement|(% style="width:351px" %)ProvisionAgreement|(% style="width:426px" %)MetadataProvisionAgreements
651 |(% style="width:321px" %)CustomTypeScheme|(% style="width:351px" %)CustomTypes|(% style="width:426px" %)CustomTypeSchemes
652 |(% style="width:321px" %)VtlMappingScheme|(% style="width:351px" %)VtlMappings|(% style="width:426px" %)VtlMappingSchemes
653 |(% style="width:321px" %)NamePersonalisationScheme|(% style="width:351px" %)NamePersonalisations|(% style="width:426px" %)NamePersonalisationSchemes
654 |(% style="width:321px" %)RulesetScheme|(% style="width:351px" %)Rulesets|(% style="width:426px" %)RulesetSchemes
655 |(% style="width:321px" %)TransformationScheme|(% style="width:351px" %)Transformations|(% style="width:426px" %)TransformationSchemes
656 |(% style="width:321px" %)UserDefinedOperatorScheme|(% style="width:351px" %)UserDefinedOperators|(% style="width:426px" %)UserDefinedOperatorSchemes
657
658 No changes have been made to the way the following artefacts are organised in the structure message:
659
660 (% style="width:1106.04px" %)
661 |(% style="width:326px" %)**Artefact type**|(% style="width:776px" %)**Collection**
662 |(% style="width:326px" %)Dataflow|(% style="width:776px" %)Dataflows
663 |(% style="width:326px" %)Metadataflow|(% style="width:776px" %)Metadataflows
664 |(% style="width:326px" %)CategoryScheme|(% style="width:776px" %)CategorySchemes
665 |(% style="width:326px" %)Categorisation|(% style="width:776px" %)Categorisations
666 |(% style="width:326px" %)Codelist|(% style="width:776px" %)Codelists
667 |(% style="width:326px" %)Hierarchy|(% style="width:776px" %)Hierarchies
668 |(% style="width:326px" %)HierarchyAssociation|(% style="width:776px" %)HierarchyAssociations
669 |(% style="width:326px" %)MetadataStructure|(% style="width:776px" %)MetadataStructures
670 |(% style="width:326px" %)DataStructure|(% style="width:776px" %)DataStructures
671 |(% style="width:326px" %)ReportingTaxonomy|(% style="width:776px" %)ReportingTaxonomies
672 |(% style="width:326px" %)Process|(% style="width:776px" %)Processes
673 |(% style="width:326px" %)ProvisionAgreement|(% style="width:776px" %)ProvisionAgreements
674
675 From version 3.0, collections can appear in any order within a structure message.
676
677 === Data messages ===
678
679 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.
680
681 Specifically, the following data messages are not supported in version 3.0:
682
683 * SDMX-ML 1.0/2.0 Generic (time-series) data message
684 * SDMX-ML 1.0/2.0 Compact (time-series) data message
685 * SDMX-ML 1.0/2.0 Utility (time-series) data message
686 * SDMX-ML 1.0/2.0 Cross-Sectional data message
687 * SDMX-ML 2.1 Generic data messages (for observations, time-series and crosssectional data)
688
689 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.
690
691 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.
692
693 The time series variant of the Structure Specific Data message is no longer used.
694
695 === Reference metadata message ===
696
697 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.
698
699 === Registry structural metadata ‘query’ messages ===
700
701 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.
702
703 === Structure referencing ===
704
705 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.
706
707 == //6.2 SDMX-JSON// ==
708
709 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.
710
711 === Structure message ===
712
713 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.
714
715 === Data message ===
716
717 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.
718
719 === Reference metadata message ===
720
721 The SDMX-JSON metadata message has also been updated to support the version 3.0 reference metadata and Metadataset specifications.
722
723 === Structure referencing ===
724
725 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.
726
727 == //6.3 SDMX-CSV// ==
728
729 CSV in SDMX is used transmission of data and reference metadata only.
730
731 === Data message ===
732
733 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:
734
735 * 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
736
737 ESTAT:NA_MAIN(1.6.0) which replaces the dataflow identifier in version 2.1; and
738
739 * 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.
740
741 === Reference metadata message ===
742
743 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.
744
745 === //6.4 EDI deprecation// ===
746
747 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.
748
749 = Appendix A – Version 2.1 Information Model =
750
751 [[image:SDMX 3-0-0 Major Changes FINAL-1.0_en_5f21cdf9.png||height="319" width="718"]]