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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
93 (((
94 (% style="width:952.039px" %)
95 |(% style="width:130px" %)**SDMX-ML**|(% style="width:820px" %)(((
96 The following legacy XML data messages have been deprecated:
97
98 SDMX-ML 1.0/2.0 Generic (time-series) data message
99
100 SDMX-ML 1.0/2.0 Compact (time-series) data message
101
102 SDMX-ML 1.0/2.0 Utility (time-series) data message
103
104 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)
105
106 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.
107
108 The SDMX-ML structure message is not backwardly compatible primarily due to:
109
110 * Changes to the information model
111 * Changes to the way the structures are organised into ‘collections’ within the message
112 * Deprecation of the Agency, ID, Version option for referencing of structures in messages
113 )))
114 |(% style="width:130px" %)**SDMX-JSON**|(% style="width:820px" %)(((
115 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.
116
117 The JSON structure message is not backwardly compatible primarily due to:
118
119 * Changes to the information model
120 * Changes to the way the structures are organised into ‘collections’ within the message
121 * Deprecation of the Agency, ID, Version option for referencing of structures in messages
122 )))
123 |(% style="width:130px" %)**SDMX-EDI**|(% style="width:820px" %)The EDI format for both structures and data has been deprecated.
124 |(% 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.
125 )))
126
127 == //2.3 Information Model// ==
128
129 (((
130 (% style="width:955.039px" %)
131 |(% style="width:132px" %)**Data Structure Definition**|(% style="width:819px" %)(((
132 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.
133
134 //Conversion guidance for implementors//
135
136 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.
137
138 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.
139 )))
140 |(% style="width:132px" %)**Structure mapping model**|(% style="width:819px" %)(((
141 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.
142
143 //Conversion guidance for implementors//
144
145 Version 2.1 structure sets can be practically converted to the version 3.0 structure mapping model.
146
147 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.
148 )))
149 |(% style="width:132px" %)**Reference metadata model**|(% style="width:819px" %)(((
150 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.
151
152 Version 2.1 reference metadata models are not valid in version 3.0.
153
154 //Conversion guidance for implementors//
155
156 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
157 )))
158 |(% style="width:132px" %) |(% style="width:819px" %)(((
159 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.
160
161 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.
162 )))
163 |(% style="width:132px" %)**Constraint model**|(% style="width:819px" %)(((
164 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.
165
166 //Conversion guidance for implementors//
167
168 2.1 Content Constraints can be converted without loss to the equivalent version 3.0 Data Constraint model.
169
170 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.
171 )))
172 |(% style="width:132px" %)**Hierarchical codelist structures**|(% style="width:819px" %)(((
173 The version 2.1 Hierarchical Codelist artefact has been deprecated in version 3.0 and replaced by two new artefacts, Hierarchy and Hierarchy Association.
174
175 //Conversion guidance for implementors//
176
177 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.
178
179 Conversion from the version 3.0 model to version 2.1 is possible, but with loss of the linking information
180 )))
181 )))
182
183 = 3 Information Model =
184
185 == //3.1 Version 3.0 Information Model// ==
186
187 [[image:SDMX 3-0-0 Major Changes FINAL-1.0_en_6fc573fe.png||height="404" width="718"]]
188
189 //Figure 1 Version 3.0 simplified Information Model UML class diagram with ‘heat map’ illustrating the areas with most change//
190
191 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.
192
193 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.
194
195 == //3.2 Key Changes from Version 2.1// ==
196
197 New Maintainable Artefacts
198
199 * Structure Map
200 * Representation Map
201 * Organisation Scheme Map
202 * Concept Scheme Map
203 * Category Scheme Map
204 * Reporting Taxonomy Map
205 * Value List
206 * Hierarchy
207 * Hierarchy Association
208 * Metadata Constraint
209 * Data Constraint
210 * Metadata Provision Agreement
211 * Metadata Provider Scheme
212 * Metadataset
213
214 New Identifiable Artefacts
215
216 * GeoFeatureSetCode
217 * GeoGridCode
218 * Metadata Provider
219
220 Removed Maintainable Artefacts
221
222 * Structure Set – replaced by Structure Map and the four item scheme maps
223 * Hierarchical Codelist – replaced by Hierarchy and Hierarchy Association • Constraint – replaced by Data Constraint and Metadata Constraint
224
225 Changed Maintainable Artefacts
226
227 * Data Structure Definition – support for microdatasets and reference metadata linked to data
228 * Metadataflow – simplifies exchange of reference metadata, in particular those linked to structures
229 * Metadata Structure Definition – simplified model for reference metadata
230 * Codelist – support for codelist extension and geospatial specialised codelists (GeographicCodelist, GeoGridCodelist)
231 * VTL Mapping Scheme – VTL Concept Mapping Scheme removed to align the VTL / SDMX interface with the 3.0 model
232
233 New Component Representation Types
234
235 * GeospatialInformation – a string type where the value is an expression defining a set of geographical features using a purpose-designed syntax
236
237 == //3.3 Areas Unchanged from Version 2.1// ==
238
239 The following areas of the information model are unchanged from version 2.1:
240
241 * Categories
242 * Concepts
243 * Data providers
244 * Agencies
245 * Data consumers
246 * VTL transformation and expressions – with the exception of VTL mapping scheme as already noted
247 * Reporting taxonomy
248 * Process
249
250 == //3.4 Reference Metadata// ==
251
252 Reference metadata has been substantially re-designed for version 3.0 to simplify the model and better support practical use cases.
253
254 === Simplify Metadata Structure Definition ===
255
256 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.
257
258 [[image:SDMX 3-0-0 Major Changes FINAL-1.0_en_ad5f5c97.png||height="346" width="494"]]
259
260 //Figure 2 version 2.1 Metadata Structure Definition (MSD)//
261
262 [[image:SDMX 3-0-0 Major Changes FINAL-1.0_en_f2695ed5.png||height="172" width="374"]]
263
264 //Figure 3 the simplified version 3.0 MSD//
265
266 === Change to reference metadata reported against data ===
267
268 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.
269
270 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.
271
272 For completeness, the excerpt also shows:
273
274 * OBS_STATUS – a simple observation-level data attribute
275 * TITLE – a multi-lingual data attribute
276 * SOURCE_AGENCY – a multi-value data attribute
277
278 <Obs xsi:type="dsd:ObsType" OBS_VALUE="112" OBS_STAUS=”A” TIME_PERIOD="2010-09">
279
280 <!—- complex multi-value and multi-lingual data attributes ~-~->
281
282 <Comp id="TITLE" xsi:type="ns1:TITLE_ATTRIBUTE">
283
284 <Value>
285
286 <common:Text xml:lang="en">Some English Text</common:Text>
287
288 <common:Text xml:lang="fr">Quelques textes en anglais</common:Text>
289
290 </Value>
291
292 </Comp>
293
294 <Comp id="SOURCE_AGENCY" xsi:type="ns1:SOURCE_AGENCY_ATTRIBUTE">
295
296 <Value>4F0</Value>
297
298 <Value>4D0</Value>
299
300 <Value>CZ2</Value>
301
302 </Comp>
303
304 <!—- metadata attributes are reported like in metadata messages ~-~->
305
306 <Metadata>
307
308 <Attribute id="COLLECTION">
309
310 <Attribute id="METHOD">
311
312 <Text lang="en">AAA</Text>
313
314 </Attribute>
315
316 </Attribute>
317
318 <Attribute id="CONTACT">
319
320 <Value>CONTACT 1</Value>
321
322 <Attribute id="NAME">
323
324 <Value>Contact 1 Name 1</Value>
325
326 </Attribute>
327
328 <Attribute id="NAME">
329
330 <Value>Contact 1 Name 2</Value>
331
332 </Attribute>
333
334 </Attribute>
335
336 <Attribute id="CONTACT">
337
338 <Value>CONTACT 2</Value>
339
340 <Attribute id="NAME">
341
342 <Value>Contact 2 Name 1</Value>
343
344 </Attribute>
345
346 <Attribute id="NAME">
347
348 <Value>Contact 2 Name 2</Value>
349
350 </Attribute>
351
352 </Attribute>
353
354 </Metadata>
355
356 </Obs>
357
358 === New - Metadata Provision Agreement ===
359
360 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.
361
362 === Move target to Metadataflow and Metadata Provision Agreement ===
363
364 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.
365
366 === Add maintainable properties to reference metadata ===
367
368 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.
369
370 == //3.5 Microdata Exchange// ==
371
372 Several changes have been made the Data Structure Definition to support microdata use cases in addition to aggregated time series.
373
374 === Multiple measures ===
375
376 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
377
378 Data Structure Definition, and can be either mandatory or conditional. Creating a measure with the “MEASURE” concept role applied emulates the version 2.1
379
380 MeasureDimension behaviour as illustrated in the SDMX-ML example below:
381
382 <str:MeasureList id=”MeasureDescriptor”>
383
384 <str:Measure id=”OBS_VALUE” minOccurs=”1” maxOccurs=”1” usage=”mandatory” > <str:ConceptIdentity>
385
386 <Ref id=”OBS_VALUE” maintainableParentID=”CONCEPTS” agencyID=”SDMX” maintainableParentVersion=”1.0.0” />
387
388 </str:ConceptIdentity>
389
390 <str:LocalRepresentation>
391
392 <str:TextFormat textType=”String” isMultiLingual=”true” />
393
394 </str:LocalRepresentation>
395
396 <str:ConceptRole>
397
398 <Ref id=”MEASURE” maintainableParentID=”SDMX_CONCEPT_ROLES” agencyID=”SDMX” maintainableParentVersion=”1.0.0” />
399
400 </str:ConceptRole>
401
402 </str:Measure>
403
404 ...
405
406 <str:Measure>
407
408 </str:MeasureList>
409
410 === Multi-value measures and attributes ===
411
412 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
413
414 //mandatory// or optional. In the SDMX-ML measure example above, the properties
415
416 //minOccurs=”1” maxOccurs=”1” usage=”mandatory”// specify that OBS_VALUE must be 198 reported, and can only consist of a single value.
417
418 === Attributes relationship to measures ===
419
420 In addition to attaching attributes to a specific level within the dataset, their relationship 202 to measures can also be defined.
421
422 === Value lists ===
423
424 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.
425
426 That allows ValueItems (the equivalent to Code) to contain symbols like ‘¥’ and ‘€’, but 208 also means they are not identifiable.
427
428 == //3.6 Geospatial Data Exchange// ==
429
430 The version 3.0 model has been extended to provide explicit support for geospatial data.
431
432 === GeospatialInformation type ===
433
434 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.
435
436 === Geospatial code lists ===
437
438 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:
439
440 * 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.
441 * 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.
442
443 === //3.7 Structure Mapping// ===
444
445 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.
446
447 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.
448
449 ==== Many-to-many source and target components ====
450
451 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:
452
453 Set the output component INDICATOR=”DE_A” if the input components are FREQ=”A” and REF_AREA=”DE”.
454
455 Similarly, an n-n rule may also set the values of any number of output components:
456
457 Set the output components FREQ=”A”, REF_AREA=”DE” if the input component INDICATOR=”DE_A”.
458
459 **Fixed source and target**
460
461 The Structure Map may now define input or output components which have a fixed value.
462
463 ==== Time representations mapping ====
464
465 Non SDMX time representations may now be described in a Structure Map, allowing them to be mapped into SDMX time formats.
466
467 ==== Regular expression and substring mappings ====
468
469 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.
470
471 ==== Item maps validity period ====
472
473 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.
474
475 === //3.8 Constraints// ===
476
477 Constraints in version 3.0 are modelled using two separate artefacts which replace the version 2.1 content constraint:
478
479 * data constraint for data; and
480 * metadata constraint for reference metadata.
481
482 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.
483
484 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.
485
486 The validity period definition has been moved from the constraint to the individual constraining terms, specifically CubeRegion, DataKeySet and MetadataTargetRegion providing more granular control.
487
488 Attachment constraints have been deprecated due to a lack of use cases.
489
490 === //3.9 Code List Extension// ===
491
492 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.
493
494 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.
495
496 === //3.10 Discriminated Union of Code Lists// ===
497
498 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.
499
500 === //3.11 Code Hierarchies// ===
501
502 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).
503
504 = 4 Versioning of Structural Metadata Artefacts =
505
506 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.
507
508 Semantic version numbers are three digits:
509
510 MAJOR.MINOR.PATCH
511
512 Where
513
514 * The first digit (major) indicates that changes (either new features or bug fixes) are not backward compatible.
515 * The second digit (minor) indicates that features have been added in a backward compatible manner.
516 * The third digit (patch) indicates that bugs have been fixed in a backward compatible manner.
517
518 Examples:
519
520 SDMX:CL_AREA(1.0.0)
521
522 SDMX:CL_AREA(2.3.2)
523
524 == Dependency management ==
525
526 Additional constructs are possible for dependency management when referencing structures. For instance:
527
528 2.3+.1 Means the currently latest available version >= “2.3.1” and < “3.0.0” (all backwards compatible versions >= “2.3.1”).
529
530 2+.3.1 Means the currently latest available version >= “2.3.1” (even if not backwards compatible).
531
532 == Draft structures ==
533
534 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.
535
536 MAJOR.MINOR.PATCH-EXTENSION
537
538 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.
539
540 1.10.0-unstable Alternative to -draft.
541
542 1.10.0-notfinal Alternative to -draft.
543
544 The SDMX 2.1 isFinal property is deprecated in 3.0.
545
546 = 5 REST Web Services API =
547
548 == //5.1 Simplified list of resources// ==
549
550 The version 3.0 REST API has just five main resources:
551
552 * structure
553 * data
554 * schema
555 * availability
556 * metadata
557
558 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.
559
560 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.
561
562 == //5.2 Improved data queries// ==
563
564 Data queries have been changed to provide more granular selections from contexts wider than just a Dataflow.
565
566 === Extend the context of data retrieval ===
567
568 Version 2.1 data queries always retrieved data from a single specific Dataflow. In version 3.0, the query context may be specified as:
569
570 * Dataflow;
571 * Data Structure Definition – i.e., all Dataflows that use it; or
572 * Provision Agreement – i.e., all Dataflows associated with it.
573
574 Data queries may also search across datasets, for instance “retrieve all data about a country”.
575
576 === Component-based filters ===
577
578 Expressions filtering on individual components can now be included as part of the data query URL.
579
580 /data/dataflow/ESTAT/ICP?c[REF_AREA]=CH&c[CONF_STATUS]=F
581
582 === Support for operators ===
583
584 Filter expressions can also include operators.
585
586 /data/dataflow/ESTAT/ICP?c[REF_AREA]=DE&c[ICP_ITEM]=sw:01&c[TIME_PERIOD]=ge:2015 Operators include:
587
588 (% style="width:531.039px" %)
589 |(% style="width:151px" %)eq|(% style="width:378px" %)Equals
590 |(% style="width:151px" %)ne|(% style="width:378px" %)Not equal to
591 |(% style="width:151px" %)le|(% style="width:378px" %)Less than
592 |(% style="width:151px" %)ge|(% style="width:378px" %)Greater than or equal to
593 |(% style="width:151px" %)sw|(% style="width:378px" %)Starts with
594
595 === Support for multiple keys ===
596
597 Queries can now specify multiple series keys.
598
599 /data/dataflow/ESTAT/ICP/1.0.0/M…A.ANR,M…A.INX,M…B.CTG
600
601 == //5.3 Improved reference metadata queries// ==
602
603 Reference metadata queries have been improved with a number of new options to retrieve metadata reports.
604
605 **Get metadata reports by ID**
606
607 /metadata/metadataset/ESTAT/QUALITY_REPORT/1.0.0
608
609 **Get metadata reports by Dataflow**
610
611 /metadata/metadataflow/ECB/METHODOLOGY/*/FR2
612
613 **Get metadata reports about a Data Structure Definition**
614
615 /metadata/structure/datastructure/BIS/BIS_CBS/1.0
616
617 == //5.4 Structural metadata maintenance// ==
618
619 Support has been added for maintenance of structural metadata.
620
621 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.
622
623 = 6 XML, JSON, CSV and EDI Transmission formats =
624
625 == //6.1 SDMX-ML// ==
626
627 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.
628
629 === Structure message ===
630
631 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.
632
633 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:
634
635 (% style="width:1102.04px" %)
636 |(% style="width:321px" %)**Artefact type**|(% style="width:351px" %)**Version 2.1 Collection**|(% style="width:426px" %)**Version 3.0 Collection**
637 |(% style="width:321px" %)AgencyScheme|(% style="width:351px" %)OrganisationSchemes|(% style="width:426px" %)AgencySchemes
638 |(% style="width:321px" %)DataConsumerScheme|(% style="width:351px" %)OrganisationSchemes|(% style="width:426px" %)DataConsumerSchemes
639 |(% style="width:321px" %)DataProviderScheme|(% style="width:351px" %)OrganisationSchemes|(% style="width:426px" %)DataProviderSchemes
640 |(% style="width:321px" %)MetadataProviderScheme|(% style="width:351px" %)OrganisationSchemes|(% style="width:426px" %)MetadataProviderSchemes
641 |(% style="width:321px" %)OrganisationUnitScheme|(% style="width:351px" %)OrganisationSchemes|(% style="width:426px" %)OrganisationUnitSchemes
642 |(% style="width:321px" %)GeographicCodelist|(% style="width:351px" %)Codelists|(% style="width:426px" %)GeographicCodelists
643 |(% style="width:321px" %)GeoGridCodelist|(% style="width:351px" %)Codelists|(% style="width:426px" %)GeoGridCodelists
644 |(% style="width:321px" %)ConceptScheme|(% style="width:351px" %)Concepts|(% style="width:426px" %)ConceptSchemes
645 |(% style="width:321px" %)ValueList|(% style="width:351px" %)Codelists|(% style="width:426px" %)ValueLists
646 |(% style="width:321px" %)StructureMap|(% style="width:351px" %)StructureMappings|(% style="width:426px" %)StructureMaps
647 |(% style="width:321px" %)RepresentationMap|(% style="width:351px" %)StructureMappings|(% style="width:426px" %)RepresentationMaps
648 |(% style="width:321px" %)ConceptSchemeMap|(% style="width:351px" %)StructureMappings|(% style="width:426px" %)ConceptSchemeMaps
649 |(% style="width:321px" %)CategorySchemeMap|(% style="width:351px" %)StructureMappings|(% style="width:426px" %)CategorySchemeMaps
650 |(% style="width:321px" %)OrganisationSchemeMap|(% style="width:351px" %)StructureMappings|(% style="width:426px" %)OrganisationSchemeMaps
651 |(% style="width:321px" %)ReportingTaxonomyMap|(% style="width:351px" %)StructureMappings|(% style="width:426px" %)ReportingTaxonomyMaps
652 |(% style="width:321px" %)DataConstraint|(% style="width:351px" %)Constraints|(% style="width:426px" %)DataConstraints
653 |(% style="width:321px" %)MetadataConstraint|(% style="width:351px" %)Constraints|(% style="width:426px" %)MetadataConstraints
654 |(% style="width:321px" %)MetadataProvisionAgreement|(% style="width:351px" %)ProvisionAgreement|(% style="width:426px" %)MetadataProvisionAgreements
655 |(% style="width:321px" %)CustomTypeScheme|(% style="width:351px" %)CustomTypes|(% style="width:426px" %)CustomTypeSchemes
656 |(% style="width:321px" %)VtlMappingScheme|(% style="width:351px" %)VtlMappings|(% style="width:426px" %)VtlMappingSchemes
657 |(% style="width:321px" %)NamePersonalisationScheme|(% style="width:351px" %)NamePersonalisations|(% style="width:426px" %)NamePersonalisationSchemes
658 |(% style="width:321px" %)RulesetScheme|(% style="width:351px" %)Rulesets|(% style="width:426px" %)RulesetSchemes
659 |(% style="width:321px" %)TransformationScheme|(% style="width:351px" %)Transformations|(% style="width:426px" %)TransformationSchemes
660 |(% style="width:321px" %)UserDefinedOperatorScheme|(% style="width:351px" %)UserDefinedOperators|(% style="width:426px" %)UserDefinedOperatorSchemes
661
662 No changes have been made to the way the following artefacts are organised in the structure message:
663
664 (% style="width:1106.04px" %)
665 |(% style="width:326px" %)**Artefact type**|(% style="width:776px" %)**Collection**
666 |(% style="width:326px" %)Dataflow|(% style="width:776px" %)Dataflows
667 |(% style="width:326px" %)Metadataflow|(% style="width:776px" %)Metadataflows
668 |(% style="width:326px" %)CategoryScheme|(% style="width:776px" %)CategorySchemes
669 |(% style="width:326px" %)Categorisation|(% style="width:776px" %)Categorisations
670 |(% style="width:326px" %)Codelist|(% style="width:776px" %)Codelists
671 |(% style="width:326px" %)Hierarchy|(% style="width:776px" %)Hierarchies
672 |(% style="width:326px" %)HierarchyAssociation|(% style="width:776px" %)HierarchyAssociations
673 |(% style="width:326px" %)MetadataStructure|(% style="width:776px" %)MetadataStructures
674 |(% style="width:326px" %)DataStructure|(% style="width:776px" %)DataStructures
675 |(% style="width:326px" %)ReportingTaxonomy|(% style="width:776px" %)ReportingTaxonomies
676 |(% style="width:326px" %)Process|(% style="width:776px" %)Processes
677 |(% style="width:326px" %)ProvisionAgreement|(% style="width:776px" %)ProvisionAgreements
678
679 From version 3.0, collections can appear in any order within a structure message.
680
681 === Data messages ===
682
683 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.
684
685 Specifically, the following data messages are not supported in version 3.0:
686
687 * SDMX-ML 1.0/2.0 Generic (time-series) data message
688 * SDMX-ML 1.0/2.0 Compact (time-series) data message
689 * SDMX-ML 1.0/2.0 Utility (time-series) data message
690 * SDMX-ML 1.0/2.0 Cross-Sectional data message
691 * SDMX-ML 2.1 Generic data messages (for observations, time-series and crosssectional data)
692
693 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.
694
695 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.
696
697 The time series variant of the Structure Specific Data message is no longer used.
698
699 === Reference metadata message ===
700
701 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.
702
703 === Registry structural metadata ‘query’ messages ===
704
705 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.
706
707 === Structure referencing ===
708
709 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.
710
711 == //6.2 SDMX-JSON// ==
712
713 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.
714
715 === Structure message ===
716
717 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.
718
719 === Data message ===
720
721 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.
722
723 === Reference metadata message ===
724
725 The SDMX-JSON metadata message has also been updated to support the version 3.0 reference metadata and Metadataset specifications.
726
727 === Structure referencing ===
728
729 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.
730
731 == //6.3 SDMX-CSV// ==
732
733 CSV in SDMX is used transmission of data and reference metadata only.
734
735 === Data message ===
736
737 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:
738
739 * 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
740
741 ESTAT:NA_MAIN(1.6.0) which replaces the dataflow identifier in version 2.1; and
742
743 * 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.
744
745 === Reference metadata message ===
746
747 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.
748
749 === //6.4 EDI deprecation// ===
750
751 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.
752
753 = Appendix A – Version 2.1 Information Model =
754
755 [[image:SDMX 3-0-0 Major Changes FINAL-1.0_en_5f21cdf9.png||height="319" width="718"]]