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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
121
122 ‘collections’ within the message
123
124 * Deprecation of the Agency, ID, Version option for referencing of structures in messages
125 )))
126 |(% style="width:130px" %)**SDMX-EDI**|(% style="width:820px" %)The EDI format for both structures and data has been deprecated.
127 |(% 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.**     **
128 )))
129
130 == //2.3 Information Model// ==
131
132 :
133
134 (((
135 (% style="width:955.039px" %)
136 |(% style="width:132px" %)**Data Structure Definition**|(% style="width:819px" %)(((
137 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.
138
139 //Conversion guidance for implementors//
140
141 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.
142
143 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.
144 )))
145 |(% style="width:132px" %)**Structure mapping model**|(% style="width:819px" %)(((
146 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.
147
148 //Conversion guidance for implementors//
149
150 Version 2.1 structure sets can be practically converted to the version 3.0 structure mapping model.
151
152 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.
153 )))
154 |(% style="width:132px" %)**Reference metadata model**|(% style="width:819px" %)(((
155 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.
156
157 Version 2.1 reference metadata models are not valid in version 3.0.
158
159 //Conversion guidance for implementors//
160
161 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
162 )))
163 |(% style="width:132px" %) |(% style="width:819px" %)(((
164 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.
165
166 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.
167 )))
168 |(% style="width:132px" %)**Constraint model**|(% style="width:819px" %)(((
169 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.
170
171 //Conversion guidance for implementors//
172
173 2.1 Content Constraints can be converted without loss to the equivalent version 3.0 Data Constraint model.
174
175 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.
176 )))
177 |(% style="width:132px" %)**Hierarchical codelist structures**|(% style="width:819px" %)(((
178 The version 2.1 Hierarchical Codelist artefact has been deprecated in version 3.0 and replaced by two new artefacts, Hierarchy and Hierarchy Association.
179
180 //Conversion guidance for implementors//
181
182 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.
183
184 Conversion from the version 3.0 model to version 2.1 is possible, but with loss of the linking information
185 )))
186 )))
187
188 = 3 Information Model =
189
190 == //3.1 Version 3.0 Information Model// ==
191
192 [[image:SDMX 3-0-0 Major Changes FINAL-1.0_en_6fc573fe.png||height="404" width="718"]]
193
194 //Figure 1 Version 3.0 simplified Information Model UML class diagram with ‘heat map’ illustrating the areas with most change//
195
196 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.
197
198 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.
199
200 == //3.2 Key Changes from Version 2.1// ==
201
202 New Maintainable Artefacts
203
204 * Structure Map
205 * Representation Map
206 * Organisation Scheme Map
207 * Concept Scheme Map
208 * Category Scheme Map
209 * Reporting Taxonomy Map
210 * Value List
211 * Hierarchy
212 * Hierarchy Association
213 * Metadata Constraint
214 * Data Constraint
215 * Metadata Provision Agreement
216 * Metadata Provider Scheme
217 * Metadataset
218
219 New Identifiable Artefacts
220
221 * GeoFeatureSetCode
222 * GeoGridCode
223 * Metadata Provider
224
225 Removed Maintainable Artefacts
226
227 * Structure Set – replaced by Structure Map and the four item scheme maps
228 * Hierarchical Codelist – replaced by Hierarchy and Hierarchy Association • Constraint – replaced by Data Constraint and Metadata Constraint
229
230 Changed Maintainable Artefacts
231
232 * Data Structure Definition – support for microdatasets and reference metadata linked to data
233 * Metadataflow – simplifies exchange of reference metadata, in particular those linked to structures
234 * Metadata Structure Definition – simplified model for reference metadata
235 * Codelist – support for codelist extension and geospatial specialised codelists (GeographicCodelist, GeoGridCodelist)
236 * VTL Mapping Scheme – VTL Concept Mapping Scheme removed to align the VTL / SDMX interface with the 3.0 model
237
238 New Component Representation Types
239
240 * GeospatialInformation – a string type where the value is an expression defining a set of geographical features using a purpose-designed syntax
241
242 == //3.3 Areas Unchanged from Version 2.1// ==
243
244 The following areas of the information model are unchanged from version 2.1:
245
246 * Categories
247 * Concepts
248 * Data providers
249 * Agencies
250 * Data consumers
251 * VTL transformation and expressions – with the exception of VTL mapping scheme as already noted
252 * Reporting taxonomy
253 * Process
254
255 == //3.4 Reference Metadata// ==
256
257 Reference metadata has been substantially re-designed for version 3.0 to simplify the model and better support practical use cases.
258
259 === Simplify Metadata Structure Definition ===
260
261 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.
262
263 [[image:SDMX 3-0-0 Major Changes FINAL-1.0_en_ad5f5c97.png||height="346" width="494"]]
264
265 //Figure 2 version 2.1 Metadata Structure Definition (MSD)//
266
267 [[image:SDMX 3-0-0 Major Changes FINAL-1.0_en_f2695ed5.png||height="172" width="374"]]
268
269 //Figure 3 the simplified version 3.0 MSD//
270
271 === Change to reference metadata reported against data ===
272
273 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.
274
275 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.
276
277 For completeness, the excerpt also shows:
278
279 * OBS_STATUS – a simple observation-level data attribute
280 * TITLE – a multi-lingual data attribute
281 * SOURCE_AGENCY – a multi-value data attribute
282
283 <Obs xsi:type="dsd:ObsType" OBS_VALUE="112" OBS_STAUS=”A” TIME_PERIOD="2010-09">
284
285 <!—- complex multi-value and multi-lingual data attributes ~-~->
286
287 <Comp id="TITLE" xsi:type="ns1:TITLE_ATTRIBUTE">
288
289 <Value>
290
291 <common:Text xml:lang="en">Some English Text</common:Text>
292
293 <common:Text xml:lang="fr">Quelques textes en anglais</common:Text>
294
295 </Value>
296
297 </Comp>
298
299 <Comp id="SOURCE_AGENCY" xsi:type="ns1:SOURCE_AGENCY_ATTRIBUTE">
300
301 <Value>4F0</Value>
302
303 <Value>4D0</Value>
304
305 <Value>CZ2</Value>
306
307 </Comp>
308
309 <!—- metadata attributes are reported like in metadata messages ~-~->
310
311 <Metadata>
312
313 <Attribute id="COLLECTION">
314
315 <Attribute id="METHOD">
316
317 <Text lang="en">AAA</Text>
318
319 </Attribute>
320
321 </Attribute>
322
323 <Attribute id="CONTACT">
324
325 <Value>CONTACT 1</Value>
326
327 <Attribute id="NAME">
328
329 <Value>Contact 1 Name 1</Value>
330
331 </Attribute>
332
333 <Attribute id="NAME">
334
335 <Value>Contact 1 Name 2</Value>
336
337 </Attribute>
338
339 </Attribute>
340
341 <Attribute id="CONTACT">
342
343 <Value>CONTACT 2</Value>
344
345 <Attribute id="NAME">
346
347 <Value>Contact 2 Name 1</Value>
348
349 </Attribute>
350
351 <Attribute id="NAME">
352
353 <Value>Contact 2 Name 2</Value>
354
355 </Attribute>
356
357 </Attribute>
358
359 </Metadata>
360
361 </Obs>
362
363 === New - Metadata Provision Agreement ===
364
365 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.
366
367 === Move target to Metadataflow and Metadata Provision Agreement ===
368
369 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.
370
371 === Add maintainable properties to reference metadata ===
372
373 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.
374
375 == //3.5 Microdata Exchange// ==
376
377 Several changes have been made the Data Structure Definition to support microdata use cases in addition to aggregated time series.
378
379 === Multiple measures ===
380
381 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
382
383 Data Structure Definition, and can be either mandatory or conditional. Creating a measure with the “MEASURE” concept role applied emulates the version 2.1
384
385 MeasureDimension behaviour as illustrated in the SDMX-ML example below:
386
387 <str:MeasureList id=”MeasureDescriptor”>
388
389 <str:Measure id=”OBS_VALUE” minOccurs=”1” maxOccurs=”1” usage=”mandatory” > <str:ConceptIdentity>
390
391 <Ref id=”OBS_VALUE” maintainableParentID=”CONCEPTS” agencyID=”SDMX” maintainableParentVersion=”1.0.0” />
392
393 </str:ConceptIdentity>
394
395 <str:LocalRepresentation>
396
397 <str:TextFormat textType=”String” isMultiLingual=”true” />
398
399 </str:LocalRepresentation>
400
401 <str:ConceptRole>
402
403 <Ref id=”MEASURE” maintainableParentID=”SDMX_CONCEPT_ROLES” agencyID=”SDMX” maintainableParentVersion=”1.0.0” />
404
405 </str:ConceptRole>
406
407 </str:Measure>
408
409 ...
410
411 <str:Measure>
412
413 </str:MeasureList>
414
415 === Multi-value measures and attributes ===
416
417 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
418
419 //mandatory// or optional. In the SDMX-ML measure example above, the properties
420
421 //minOccurs=”1” maxOccurs=”1” usage=”mandatory”// specify that OBS_VALUE must be 198 reported, and can only consist of a single value.
422
423 === Attributes relationship to measures ===
424
425 In addition to attaching attributes to a specific level within the dataset, their relationship 202 to measures can also be defined.
426
427 === Value lists ===
428
429 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.
430
431 That allows ValueItems (the equivalent to Code) to contain symbols like ‘¥’ and ‘€’, but 208 also means they are not identifiable.
432
433 == //3.6 Geospatial Data Exchange// ==
434
435 The version 3.0 model has been extended to provide explicit support for geospatial data.
436
437 === GeospatialInformation type ===
438
439 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.
440
441 === Geospatial code lists ===
442
443 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:
444
445 * 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.
446 * 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.
447
448 === //3.7 Structure Mapping// ===
449
450 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.
451
452 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.
453
454 ==== Many-to-many source and target components ====
455
456 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:
457
458 Set the output component INDICATOR=”DE_A” if the input components are FREQ=”A” and REF_AREA=”DE”.
459
460 Similarly, an n-n rule may also set the values of any number of output components:
461
462 Set the output components FREQ=”A”, REF_AREA=”DE” if the input component INDICATOR=”DE_A”.
463
464 **Fixed source and target**
465
466 The Structure Map may now define input or output components which have a fixed value.
467
468 ==== Time representations mapping ====
469
470 Non SDMX time representations may now be described in a Structure Map, allowing them to be mapped into SDMX time formats.
471
472 ==== Regular expression and substring mappings ====
473
474 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.
475
476 ==== Item maps validity period ====
477
478 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.
479
480 === //3.8 Constraints// ===
481
482 Constraints in version 3.0 are modelled using two separate artefacts which replace the version 2.1 content constraint:
483
484 * data constraint for data; and
485 * metadata constraint for reference metadata.
486
487 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.
488
489 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.
490
491 The validity period definition has been moved from the constraint to the individual constraining terms, specifically CubeRegion, DataKeySet and MetadataTargetRegion providing more granular control.
492
493 Attachment constraints have been deprecated due to a lack of use cases.
494
495 === //3.9 Code List Extension// ===
496
497 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.
498
499 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.
500
501 === //3.10 Discriminated Union of Code Lists// ===
502
503 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.
504
505 === //3.11 Code Hierarchies// ===
506
507 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).
508
509 = 4 Versioning of Structural Metadata Artefacts =
510
511 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.
512
513 Semantic version numbers are three digits:
514
515 MAJOR.MINOR.PATCH
516
517 Where
518
519 * The first digit (major) indicates that changes (either new features or bug fixes) are not backward compatible.
520 * The second digit (minor) indicates that features have been added in a backward compatible manner.
521 * The third digit (patch) indicates that bugs have been fixed in a backward compatible manner.
522
523 Examples:
524
525 SDMX:CL_AREA(1.0.0)
526
527 SDMX:CL_AREA(2.3.2)
528
529 == Dependency management ==
530
531 Additional constructs are possible for dependency management when referencing structures. For instance:
532
533 2.3+.1 Means the currently latest available version >= “2.3.1” and < “3.0.0” (all backwards compatible versions >= “2.3.1”).
534
535 2+.3.1 Means the currently latest available version >= “2.3.1” (even if not backwards compatible).
536
537 == Draft structures ==
538
539 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.
540
541 MAJOR.MINOR.PATCH-EXTENSION
542
543 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.
544
545 1.10.0-unstable Alternative to -draft.
546
547 1.10.0-notfinal Alternative to -draft.
548
549 The SDMX 2.1 isFinal property is deprecated in 3.0.
550
551 = 5 REST Web Services API =
552
553 == //5.1 Simplified list of resources// ==
554
555 The version 3.0 REST API has just five main resources:
556
557 * structure
558 * data
559 * schema
560 * availability
561 * metadata
562
563 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.
564
565 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.
566
567 == //5.2 Improved data queries// ==
568
569 Data queries have been changed to provide more granular selections from contexts wider than just a Dataflow.
570
571 === Extend the context of data retrieval ===
572
573 Version 2.1 data queries always retrieved data from a single specific Dataflow. In version 3.0, the query context may be specified as:
574
575 * Dataflow;
576 * Data Structure Definition – i.e., all Dataflows that use it; or
577 * Provision Agreement – i.e., all Dataflows associated with it.
578
579 Data queries may also search across datasets, for instance “retrieve all data about a country”.
580
581 === Component-based filters ===
582
583 Expressions filtering on individual components can now be included as part of the data query URL.
584
585 /data/dataflow/ESTAT/ICP?c[REF_AREA]=CH&c[CONF_STATUS]=F
586
587 === Support for operators ===
588
589 Filter expressions can also include operators.
590
591 /data/dataflow/ESTAT/ICP?c[REF_AREA]=DE&c[ICP_ITEM]=sw:01&c[TIME_PERIOD]=ge:2015 Operators include:
592
593 (% style="width:531.039px" %)
594 |(% style="width:151px" %)eq|(% style="width:378px" %)Equals
595 |(% style="width:151px" %)ne|(% style="width:378px" %)Not equal to
596 |(% style="width:151px" %)le|(% style="width:378px" %)Less than
597 |(% style="width:151px" %)ge|(% style="width:378px" %)Greater than or equal to
598 |(% style="width:151px" %)sw|(% style="width:378px" %)Starts with
599
600 === Support for multiple keys ===
601
602 Queries can now specify multiple series keys.
603
604 /data/dataflow/ESTAT/ICP/1.0.0/M…A.ANR,M…A.INX,M…B.CTG
605
606 == //5.3 Improved reference metadata queries// ==
607
608 Reference metadata queries have been improved with a number of new options to retrieve metadata reports.
609
610 **Get metadata reports by ID**
611
612 /metadata/metadataset/ESTAT/QUALITY_REPORT/1.0.0
613
614 **Get metadata reports by Dataflow**
615
616 /metadata/metadataflow/ECB/METHODOLOGY/*/FR2
617
618 **Get metadata reports about a Data Structure Definition**
619
620 /metadata/structure/datastructure/BIS/BIS_CBS/1.0
621
622 == //5.4 Structural metadata maintenance// ==
623
624 Support has been added for maintenance of structural metadata.
625
626 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.
627
628 = 6 XML, JSON, CSV and EDI Transmission formats =
629
630 == //6.1 SDMX-ML// ==
631
632 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.
633
634 === Structure message ===
635
636 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.
637
638 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:
639
640 (% style="width:1102.04px" %)
641 |(% style="width:321px" %)**Artefact type**|(% style="width:351px" %)**Version 2.1 Collection**|(% style="width:426px" %)**Version 3.0 Collection**
642 |(% style="width:321px" %)AgencyScheme|(% style="width:351px" %)OrganisationSchemes|(% style="width:426px" %)AgencySchemes
643 |(% style="width:321px" %)DataConsumerScheme|(% style="width:351px" %)OrganisationSchemes|(% style="width:426px" %)DataConsumerSchemes
644 |(% style="width:321px" %)DataProviderScheme|(% style="width:351px" %)OrganisationSchemes|(% style="width:426px" %)DataProviderSchemes
645 |(% style="width:321px" %)MetadataProviderScheme|(% style="width:351px" %)OrganisationSchemes|(% style="width:426px" %)MetadataProviderSchemes
646 |(% style="width:321px" %)OrganisationUnitScheme|(% style="width:351px" %)OrganisationSchemes|(% style="width:426px" %)OrganisationUnitSchemes
647 |(% style="width:321px" %)GeographicCodelist|(% style="width:351px" %)Codelists|(% style="width:426px" %)GeographicCodelists
648 |(% style="width:321px" %)GeoGridCodelist|(% style="width:351px" %)Codelists|(% style="width:426px" %)GeoGridCodelists
649 |(% style="width:321px" %)ConceptScheme|(% style="width:351px" %)Concepts|(% style="width:426px" %)ConceptSchemes
650 |(% style="width:321px" %)ValueList|(% style="width:351px" %)Codelists|(% style="width:426px" %)ValueLists
651 |(% style="width:321px" %)StructureMap|(% style="width:351px" %)StructureMappings|(% style="width:426px" %)StructureMaps
652 |(% style="width:321px" %)RepresentationMap|(% style="width:351px" %)StructureMappings|(% style="width:426px" %)RepresentationMaps
653 |(% style="width:321px" %)ConceptSchemeMap|(% style="width:351px" %)StructureMappings|(% style="width:426px" %)ConceptSchemeMaps
654 |(% style="width:321px" %)CategorySchemeMap|(% style="width:351px" %)StructureMappings|(% style="width:426px" %)CategorySchemeMaps
655 |(% style="width:321px" %)OrganisationSchemeMap|(% style="width:351px" %)StructureMappings|(% style="width:426px" %)OrganisationSchemeMaps
656 |(% style="width:321px" %)ReportingTaxonomyMap|(% style="width:351px" %)StructureMappings|(% style="width:426px" %)ReportingTaxonomyMaps
657 |(% style="width:321px" %)DataConstraint|(% style="width:351px" %)Constraints|(% style="width:426px" %)DataConstraints
658 |(% style="width:321px" %)MetadataConstraint|(% style="width:351px" %)Constraints|(% style="width:426px" %)MetadataConstraints
659 |(% style="width:321px" %)MetadataProvisionAgreement|(% style="width:351px" %)ProvisionAgreement|(% style="width:426px" %)MetadataProvisionAgreements
660 |(% style="width:321px" %)CustomTypeScheme|(% style="width:351px" %)CustomTypes|(% style="width:426px" %)CustomTypeSchemes
661 |(% style="width:321px" %)VtlMappingScheme|(% style="width:351px" %)VtlMappings|(% style="width:426px" %)VtlMappingSchemes
662 |(% style="width:321px" %)NamePersonalisationScheme|(% style="width:351px" %)NamePersonalisations|(% style="width:426px" %)NamePersonalisationSchemes
663 |(% style="width:321px" %)RulesetScheme|(% style="width:351px" %)Rulesets|(% style="width:426px" %)RulesetSchemes
664 |(% style="width:321px" %)TransformationScheme|(% style="width:351px" %)Transformations|(% style="width:426px" %)TransformationSchemes
665 |(% style="width:321px" %)UserDefinedOperatorScheme|(% style="width:351px" %)UserDefinedOperators|(% style="width:426px" %)UserDefinedOperatorSchemes
666
667 No changes have been made to the way the following artefacts are organised in the structure message:
668
669 (% style="width:1106.04px" %)
670 |(% style="width:326px" %)**Artefact type**|(% style="width:776px" %)**Collection**
671 |(% style="width:326px" %)Dataflow|(% style="width:776px" %)Dataflows
672 |(% style="width:326px" %)Metadataflow|(% style="width:776px" %)Metadataflows
673 |(% style="width:326px" %)CategoryScheme|(% style="width:776px" %)CategorySchemes
674 |(% style="width:326px" %)Categorisation|(% style="width:776px" %)Categorisations
675 |(% style="width:326px" %)Codelist|(% style="width:776px" %)Codelists
676 |(% style="width:326px" %)Hierarchy|(% style="width:776px" %)Hierarchies
677 |(% style="width:326px" %)HierarchyAssociation|(% style="width:776px" %)HierarchyAssociations
678 |(% style="width:326px" %)MetadataStructure|(% style="width:776px" %)MetadataStructures
679 |(% style="width:326px" %)DataStructure|(% style="width:776px" %)DataStructures
680 |(% style="width:326px" %)ReportingTaxonomy|(% style="width:776px" %)ReportingTaxonomies
681 |(% style="width:326px" %)Process|(% style="width:776px" %)Processes
682 |(% style="width:326px" %)ProvisionAgreement|(% style="width:776px" %)ProvisionAgreements
683
684 From version 3.0, collections can appear in any order within a structure message.
685
686 === Data messages ===
687
688 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.
689
690 Specifically, the following data messages are not supported in version 3.0:
691
692 * SDMX-ML 1.0/2.0 Generic (time-series) data message
693 * SDMX-ML 1.0/2.0 Compact (time-series) data message
694 * SDMX-ML 1.0/2.0 Utility (time-series) data message
695 * SDMX-ML 1.0/2.0 Cross-Sectional data message
696 * SDMX-ML 2.1 Generic data messages (for observations, time-series and crosssectional data)
697
698 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.
699
700 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.
701
702 The time series variant of the Structure Specific Data message is no longer used.
703
704 === Reference metadata message ===
705
706 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.
707
708 === Registry structural metadata ‘query’ messages ===
709
710 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.
711
712 === Structure referencing ===
713
714 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.
715
716 == //6.2 SDMX-JSON// ==
717
718 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.
719
720 === Structure message ===
721
722 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.
723
724 === Data message ===
725
726 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.
727
728 === Reference metadata message ===
729
730 The SDMX-JSON metadata message has also been updated to support the version 3.0 reference metadata and Metadataset specifications.
731
732 === Structure referencing ===
733
734 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.
735
736 == //6.3 SDMX-CSV// ==
737
738 CSV in SDMX is used transmission of data and reference metadata only.
739
740 === Data message ===
741
742 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:
743
744 * 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
745
746 ESTAT:NA_MAIN(1.6.0) which replaces the dataflow identifier in version 2.1; and
747
748 * 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.
749
750 === Reference metadata message ===
751
752 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.
753
754 === //6.4 EDI deprecation// ===
755
756 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.
757
758 = Appendix A – Version 2.1 Information Model =
759
760 [[image:SDMX 3-0-0 Major Changes FINAL-1.0_en_5f21cdf9.png||height="319" width="718"]]