Changes for page 12 Validation and Transformation Language (VTL)

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From 10.3 to 10.4 From 10.10 to 10.11

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@@ -110,8 +110,6 @@
  * As said, the container-object-id does not apply to the classes that can be referenced in [[VTL>>doc:sdmx:Glossary 2\.1.Validation and transformation language.WebHome]] Transformations, therefore is not present in their URN
  * The object-id does not exist for the [[artefacts>>doc:sdmx:Glossary 2\.1.Artefact.WebHome]] belonging to the [[Dataflow>>doc:sdmx:Glossary 2\.1.Dataflow.WebHome]], and [[Codelist>>doc:sdmx:Glossary 2\.1.Code list.WebHome]] classes, while it exists and cannot be omitted for the [[artefacts>>doc:sdmx:Glossary 2\.1.Artefact.WebHome]] belonging to the classes [[Dimension>>doc:sdmx:Glossary 2\.1.Dimension.WebHome]], TimeDimension, [[Measure>>doc:sdmx:Glossary 2\.1.Measure.WebHome]], DataAttribute and [[Concept>>doc:sdmx:Glossary 2\.1.Concept.WebHome]], as for them the object-id is the main identifier of the [[artefact>>doc:sdmx:Glossary 2\.1.Artefact.WebHome]]
--
--
  The simplified object identifier is obtained by omitting all the first part of the URN, including the special characters, till the first part not omitted.
  For example, the full formulation that uses the complete URN shown at the end of the previous paragraph:
@@ -144,9 +144,9 @@
  > 'DFR(1.0.0)' := 'DF1(1.0.0)' [rename SECTOR to SEC]
--In the references to the (% style="color:#e74c3c" %)Concepts(%%), which can exist for example in the definition of the [[VTL>>doc:sdmx:Glossary 2\.1.Validation and transformation language.WebHome]] Rulesets, at least the conceptScheme-id and the (% style="color:#e74c3c" %)concept(%%)-id must be specified.
++In the references to the [[Concepts>>doc:sdmx:Glossary 2\.1.Concept.WebHome]], which can exist for example in the definition of the [[VTL>>doc:sdmx:Glossary 2\.1.Validation and transformation language.WebHome]] Rulesets, at least the conceptScheme-id and the [[concept>>doc:sdmx:Glossary 2\.1.Concept.WebHome]]-id must be specified.
--An example of non-abbreviated reference, if the conceptScheme-id is CS1 and the (% style="color:#e74c3c" %)concept(%%)-id is [[SECTOR>>doc:sdmx:Glossary 2\.1.Sector.WebHome]], is the following:
++An example of non-abbreviated reference, if the conceptScheme-id is CS1 and the [[concept>>doc:sdmx:Glossary 2\.1.Concept.WebHome]]-id is [[SECTOR>>doc:sdmx:Glossary 2\.1.Sector.WebHome]], is the following:
  > 'urn:sdmx:org.sdmx.infomodel.conceptscheme.Concept=AG:CS1(1.0.0).SECTOR'
@@ -158,7 +158,7 @@
  > 'DFR(1.0.0)' := between ( 'DF1(1.0.0)', 0, 25000 )
--The [[artefact>>doc:sdmx:Glossary 2\.1.Artefact.WebHome]] ([[Component>>doc:sdmx:Glossary 2\.1.Component.WebHome]], (% style="color:#e74c3c" %)Concept(%%), [[Codelist>>doc:sdmx:Glossary 2\.1.Code list.WebHome]] …) which the Values are referred to can be deduced from the context in which the reference is made, taking also into account the [[VTL>>doc:sdmx:Glossary 2\.1.Validation and transformation language.WebHome]] syntax. In the Transformation above, for example, the values 0 and 2500 are compared to the values of the [[measures>>doc:sdmx:Glossary 2\.1.Measure.WebHome]] of DF1(1.0.0).
++The [[artefact>>doc:sdmx:Glossary 2\.1.Artefact.WebHome]] ([[Component>>doc:sdmx:Glossary 2\.1.Component.WebHome]], [[Concept>>doc:sdmx:Glossary 2\.1.Concept.WebHome]], [[Codelist>>doc:sdmx:Glossary 2\.1.Code list.WebHome]] …) which the Values are referred to can be deduced from the context in which the reference is made, taking also into account the [[VTL>>doc:sdmx:Glossary 2\.1.Validation and transformation language.WebHome]] syntax. In the Transformation above, for example, the values 0 and 2500 are compared to the values of the [[measures>>doc:sdmx:Glossary 2\.1.Measure.WebHome]] of DF1(1.0.0).
  === 12.2.4 User-defined alias ===
@@ -172,29 +172,29 @@
  The [[VTL>>doc:sdmx:Glossary 2\.1.Validation and transformation language.WebHome]] Rulesets have a signature, in which the Value Domains or the [[Variables>>doc:sdmx:Glossary 2\.1.Statistical variable.WebHome]] on which the Ruleset is defined are declared, and a body, which contains the Rules.
--In the signature, given the (% style="color:#e74c3c" %)mapping(%%) between [[VTL>>doc:sdmx:Glossary 2\.1.Validation and transformation language.WebHome]] and [[SDMX>>doc:sdmx:Glossary 2\.1.Statistical data and metadata exchange.WebHome]] better described in the following paragraphs, a reference to a [[VTL>>doc:sdmx:Glossary 2\.1.Validation and transformation language.WebHome]] Value Domain becomes a reference to a [[SDMX>>doc:sdmx:Glossary 2\.1.Statistical data and metadata exchange.WebHome]] [[Codelist>>doc:sdmx:Glossary 2\.1.Code list.WebHome]], while a reference to a [[VTL>>doc:sdmx:Glossary 2\.1.Validation and transformation language.WebHome]] Represented [[Variable>>doc:sdmx:Glossary 2\.1.Statistical variable.WebHome]] becomes a reference to a [[SDMX>>doc:sdmx:Glossary 2\.1.Statistical data and metadata exchange.WebHome]] (% style="color:#e74c3c" %)Concept(%%), assuming for it a definite [[representation>>doc:sdmx:Glossary 2\.1.Representation.WebHome]]{{footnote}}Rulesets of this kind cannot be reused when the referenced Concept has a different representation.{{/footnote}}.
++In the signature, given the mapping between [[VTL>>doc:sdmx:Glossary 2\.1.Validation and transformation language.WebHome]] and [[SDMX>>doc:sdmx:Glossary 2\.1.Statistical data and metadata exchange.WebHome]] better described in the following paragraphs, a reference to a [[VTL>>doc:sdmx:Glossary 2\.1.Validation and transformation language.WebHome]] Value Domain becomes a reference to a [[SDMX>>doc:sdmx:Glossary 2\.1.Statistical data and metadata exchange.WebHome]] [[Codelist>>doc:sdmx:Glossary 2\.1.Code list.WebHome]], while a reference to a [[VTL>>doc:sdmx:Glossary 2\.1.Validation and transformation language.WebHome]] Represented [[Variable>>doc:sdmx:Glossary 2\.1.Statistical variable.WebHome]] becomes a reference to a [[SDMX>>doc:sdmx:Glossary 2\.1.Statistical data and metadata exchange.WebHome]] [[Concept>>doc:sdmx:Glossary 2\.1.Concept.WebHome]], assuming for it a definite [[representation>>doc:sdmx:Glossary 2\.1.Representation.WebHome]]{{footnote}}Rulesets of this kind cannot be reused when the referenced Concept has a different representation.{{/footnote}}.
--In general, for referencing [[SDMX>>doc:sdmx:Glossary 2\.1.Statistical data and metadata exchange.WebHome]] [[Codelists>>doc:sdmx:Glossary 2\.1.Code list.WebHome]] and (% style="color:#e74c3c" %)Concepts(%%), the conventions described in the previous paragraphs apply. In the Ruleset syntax, the elements that reference [[SDMX>>doc:sdmx:Glossary 2\.1.Statistical data and metadata exchange.WebHome]] [[artefacts>>doc:sdmx:Glossary 2\.1.Artefact.WebHome]] are called "valueDomain" and "[[variable>>doc:sdmx:Glossary 2\.1.Statistical variable.WebHome]]" for the Datapoint Rulesets and "ruleValueDomain", "ruleVariable", "condValueDomain" "condVariable" for the Hierarchical Rulesets).
++In general, for referencing [[SDMX>>doc:sdmx:Glossary 2\.1.Statistical data and metadata exchange.WebHome]] [[Codelists>>doc:sdmx:Glossary 2\.1.Code list.WebHome]] and [[Concepts>>doc:sdmx:Glossary 2\.1.Concept.WebHome]], the conventions described in the previous paragraphs apply. In the Ruleset syntax, the elements that reference [[SDMX>>doc:sdmx:Glossary 2\.1.Statistical data and metadata exchange.WebHome]] [[artefacts>>doc:sdmx:Glossary 2\.1.Artefact.WebHome]] are called "valueDomain" and "[[variable>>doc:sdmx:Glossary 2\.1.Statistical variable.WebHome]]" for the Datapoint Rulesets and "ruleValueDomain", "ruleVariable", "condValueDomain" "condVariable" for the Hierarchical Rulesets).
--The syntax of the Ruleset signature allows also to define aliases of the elements above, these aliases are valid only within the specific Ruleset definition statement and cannot be (% style="color:#e74c3c" %)mapped(%%) to [[SDMX>>doc:sdmx:Glossary 2\.1.Statistical data and metadata exchange.WebHome]].{{footnote}}See also the section "VTL-DL Rulesets" in the VTL Reference Manual.{{/footnote}}
++The syntax of the Ruleset signature allows also to define aliases of the elements above, these aliases are valid only within the specific Ruleset definition statement and cannot be mapped to [[SDMX>>doc:sdmx:Glossary 2\.1.Statistical data and metadata exchange.WebHome]].{{footnote}}See also the section "VTL-DL Rulesets" in the VTL Reference Manual.{{/footnote}}
--In the body of the Rulesets, the [[Codes>>doc:sdmx:Glossary 2\.1.Code.WebHome]] and in general all the Values can be written without any other specification, because the [[artefact>>doc:sdmx:Glossary 2\.1.Artefact.WebHome]], which the Values are referred ([[Codelist>>doc:sdmx:Glossary 2\.1.Code list.WebHome]], (% style="color:#e74c3c" %)Concept(%%)) to can be deduced from the Ruleset signature.
++In the body of the Rulesets, the [[Codes>>doc:sdmx:Glossary 2\.1.Code.WebHome]] and in general all the Values can be written without any other specification, because the [[artefact>>doc:sdmx:Glossary 2\.1.Artefact.WebHome]], which the Values are referred ([[Codelist>>doc:sdmx:Glossary 2\.1.Code list.WebHome]], [[Concept>>doc:sdmx:Glossary 2\.1.Concept.WebHome]]) to can be deduced from the Ruleset signature.
  == 12.3 Mapping between SDMX and VTL artefacts ==
  === 12.3.1. When the mapping occurs ===
--The (% style="color:#e74c3c" %)mapping(%%) methods between the [[VTL>>doc:sdmx:Glossary 2\.1.Validation and transformation language.WebHome]] and [[SDMX>>doc:sdmx:Glossary 2\.1.Statistical data and metadata exchange.WebHome]] object classes allow transforming a [[SDMX>>doc:sdmx:Glossary 2\.1.Statistical data and metadata exchange.WebHome]] definition in a [[VTL>>doc:sdmx:Glossary 2\.1.Validation and transformation language.WebHome]] one and vice-versa for the [[artefacts>>doc:sdmx:Glossary 2\.1.Artefact.WebHome]] to be manipulated. It should be remembered that [[VTL>>doc:sdmx:Glossary 2\.1.Validation and transformation language.WebHome]] programs (i.e. Transformation Schemes) are represented in [[SDMX>>doc:sdmx:Glossary 2\.1.Statistical data and metadata exchange.WebHome]] through the TransformationScheme maintainable class which is composed of Transformations ([[nameable artefacts>>doc:sdmx:Glossary 2\.1.Nameable artefact.WebHome]]). Each Transformation assigns the outcome of the evaluation of a [[VTL>>doc:sdmx:Glossary 2\.1.Validation and transformation language.WebHome]] expression to a result: the input operands of the expression and the result can be [[SDMX>>doc:sdmx:Glossary 2\.1.Statistical data and metadata exchange.WebHome]] [[artefacts>>doc:sdmx:Glossary 2\.1.Artefact.WebHome]]. Every time a [[SDMX>>doc:sdmx:Glossary 2\.1.Statistical data and metadata exchange.WebHome]] object is referenced in a [[VTL>>doc:sdmx:Glossary 2\.1.Validation and transformation language.WebHome]] Transformation as an input operand, there is the need to generate a [[VTL>>doc:sdmx:Glossary 2\.1.Validation and transformation language.WebHome]] definition of the object, so that the [[VTL>>doc:sdmx:Glossary 2\.1.Validation and transformation language.WebHome]] operations can take place. This can be made starting from the [[SDMX>>doc:sdmx:Glossary 2\.1.Statistical data and metadata exchange.WebHome]] definition and applying a [[SDMX>>doc:sdmx:Glossary 2\.1.Statistical data and metadata exchange.WebHome]]-[[VTL>>doc:sdmx:Glossary 2\.1.Validation and transformation language.WebHome]] (% style="color:#e74c3c" %)mapping(%%) method in the direction from [[SDMX>>doc:sdmx:Glossary 2\.1.Statistical data and metadata exchange.WebHome]] to [[VTL>>doc:sdmx:Glossary 2\.1.Validation and transformation language.WebHome]]. The possible (% style="color:#e74c3c" %)mapping(%%) methods from [[SDMX>>doc:sdmx:Glossary 2\.1.Statistical data and metadata exchange.WebHome]] to [[VTL>>doc:sdmx:Glossary 2\.1.Validation and transformation language.WebHome]] are described in the following paragraphs and are conceived to allow the automatic deduction of the [[VTL>>doc:sdmx:Glossary 2\.1.Validation and transformation language.WebHome]] definition of the object from the knowledge of the [[SDMX>>doc:sdmx:Glossary 2\.1.Statistical data and metadata exchange.WebHome]] definition.
++The mapping methods between the [[VTL>>doc:sdmx:Glossary 2\.1.Validation and transformation language.WebHome]] and [[SDMX>>doc:sdmx:Glossary 2\.1.Statistical data and metadata exchange.WebHome]] object classes allow transforming a [[SDMX>>doc:sdmx:Glossary 2\.1.Statistical data and metadata exchange.WebHome]] definition in a [[VTL>>doc:sdmx:Glossary 2\.1.Validation and transformation language.WebHome]] one and vice-versa for the [[artefacts>>doc:sdmx:Glossary 2\.1.Artefact.WebHome]] to be manipulated. It should be remembered that [[VTL>>doc:sdmx:Glossary 2\.1.Validation and transformation language.WebHome]] programs (i.e. Transformation Schemes) are represented in [[SDMX>>doc:sdmx:Glossary 2\.1.Statistical data and metadata exchange.WebHome]] through the TransformationScheme maintainable class which is composed of Transformations ([[nameable artefacts>>doc:sdmx:Glossary 2\.1.Nameable artefact.WebHome]]). Each Transformation assigns the outcome of the evaluation of a [[VTL>>doc:sdmx:Glossary 2\.1.Validation and transformation language.WebHome]] expression to a result: the input operands of the expression and the result can be [[SDMX>>doc:sdmx:Glossary 2\.1.Statistical data and metadata exchange.WebHome]] [[artefacts>>doc:sdmx:Glossary 2\.1.Artefact.WebHome]]. Every time a [[SDMX>>doc:sdmx:Glossary 2\.1.Statistical data and metadata exchange.WebHome]] object is referenced in a [[VTL>>doc:sdmx:Glossary 2\.1.Validation and transformation language.WebHome]] Transformation as an input operand, there is the need to generate a [[VTL>>doc:sdmx:Glossary 2\.1.Validation and transformation language.WebHome]] definition of the object, so that the [[VTL>>doc:sdmx:Glossary 2\.1.Validation and transformation language.WebHome]] operations can take place. This can be made starting from the [[SDMX>>doc:sdmx:Glossary 2\.1.Statistical data and metadata exchange.WebHome]] definition and applying a [[SDMX>>doc:sdmx:Glossary 2\.1.Statistical data and metadata exchange.WebHome]]-[[VTL>>doc:sdmx:Glossary 2\.1.Validation and transformation language.WebHome]] mapping method in the direction from [[SDMX>>doc:sdmx:Glossary 2\.1.Statistical data and metadata exchange.WebHome]] to [[VTL>>doc:sdmx:Glossary 2\.1.Validation and transformation language.WebHome]]. The possible mapping methods from [[SDMX>>doc:sdmx:Glossary 2\.1.Statistical data and metadata exchange.WebHome]] to [[VTL>>doc:sdmx:Glossary 2\.1.Validation and transformation language.WebHome]] are described in the following paragraphs and are conceived to allow the automatic deduction of the [[VTL>>doc:sdmx:Glossary 2\.1.Validation and transformation language.WebHome]] definition of the object from the knowledge of the [[SDMX>>doc:sdmx:Glossary 2\.1.Statistical data and metadata exchange.WebHome]] definition.
  In the opposite direction, every time an object calculated by means of [[VTL>>doc:sdmx:Glossary 2\.1.Validation and transformation language.WebHome]] must be treated as a [[SDMX>>doc:sdmx:Glossary 2\.1.Statistical data and metadata exchange.WebHome]] object (for example for exchanging it through [[SDMX>>doc:sdmx:Glossary 2\.1.Statistical data and metadata exchange.WebHome]]), there is the need of a [[SDMX>>doc:sdmx:Glossary 2\.1.Statistical data and metadata exchange.WebHome]] definition of the object, so that the [[SDMX>>doc:sdmx:Glossary 2\.1.Statistical data and metadata exchange.WebHome]] operations can take place. The [[SDMX>>doc:sdmx:Glossary 2\.1.Statistical data and metadata exchange.WebHome]] definition is needed for the [[VTL>>doc:sdmx:Glossary 2\.1.Validation and transformation language.WebHome]] objects for which a [[SDMX>>doc:sdmx:Glossary 2\.1.Statistical data and metadata exchange.WebHome]] use is envisaged{{footnote}}If a calculated artefact is persistent, it needs a persistent definition, i.e. a SDMX definition in a SDMX environment. In addition, possible calculated artefact that are not persistent may require a SDMX definition, for example when the result of a nonpersistent calculation is disseminated through SDMX tools (like an inquiry tool).{{/footnote}}.
--The (% style="color:#e74c3c" %)mapping(%%) methods from [[VTL>>doc:sdmx:Glossary 2\.1.Validation and transformation language.WebHome]] to [[SDMX>>doc:sdmx:Glossary 2\.1.Statistical data and metadata exchange.WebHome]] are described in the following paragraphs as well, however they do not allow the complete [[SDMX>>doc:sdmx:Glossary 2\.1.Statistical data and metadata exchange.WebHome]] definition to be automatically deduced from the [[VTL>>doc:sdmx:Glossary 2\.1.Validation and transformation language.WebHome]] definition, more than all because the former typically contains additional information in respect to the latter. For example, the definition of a [[SDMX>>doc:sdmx:Glossary 2\.1.Statistical data and metadata exchange.WebHome]] [[DSD>>doc:sdmx:Glossary 2\.1.Data structure definition.WebHome]] includes also some mandatory information not available in [[VTL>>doc:sdmx:Glossary 2\.1.Validation and transformation language.WebHome]] (like the [[concept scheme>>doc:sdmx:Glossary 2\.1.Concept scheme.WebHome]] to which the [[SDMX>>doc:sdmx:Glossary 2\.1.Statistical data and metadata exchange.WebHome]] [[components>>doc:sdmx:Glossary 2\.1.Component.WebHome]] refer, the ‘usage’ and ‘attributeRelationship’ for the DataAttributes and so on). Therefore the (% style="color:#e74c3c" %)mapping(%%) methods from [[VTL>>doc:sdmx:Glossary 2\.1.Validation and transformation language.WebHome]] to [[SDMX>>doc:sdmx:Glossary 2\.1.Statistical data and metadata exchange.WebHome]] provide only a general guidance for generating [[SDMX>>doc:sdmx:Glossary 2\.1.Statistical data and metadata exchange.WebHome]] definitions properly starting from the information available in [[VTL>>doc:sdmx:Glossary 2\.1.Validation and transformation language.WebHome]], independently of how the [[SDMX>>doc:sdmx:Glossary 2\.1.Statistical data and metadata exchange.WebHome]] definition it is actually generated (manually, automatically or part and part).
++The mapping methods from [[VTL>>doc:sdmx:Glossary 2\.1.Validation and transformation language.WebHome]] to [[SDMX>>doc:sdmx:Glossary 2\.1.Statistical data and metadata exchange.WebHome]] are described in the following paragraphs as well, however they do not allow the complete [[SDMX>>doc:sdmx:Glossary 2\.1.Statistical data and metadata exchange.WebHome]] definition to be automatically deduced from the [[VTL>>doc:sdmx:Glossary 2\.1.Validation and transformation language.WebHome]] definition, more than all because the former typically contains additional information in respect to the latter. For example, the definition of a [[SDMX>>doc:sdmx:Glossary 2\.1.Statistical data and metadata exchange.WebHome]] [[DSD>>doc:sdmx:Glossary 2\.1.Data structure definition.WebHome]] includes also some mandatory information not available in [[VTL>>doc:sdmx:Glossary 2\.1.Validation and transformation language.WebHome]] (like the [[concept scheme>>doc:sdmx:Glossary 2\.1.Concept scheme.WebHome]] to which the [[SDMX>>doc:sdmx:Glossary 2\.1.Statistical data and metadata exchange.WebHome]] [[components>>doc:sdmx:Glossary 2\.1.Component.WebHome]] refer, the ‘usage’ and ‘attributeRelationship’ for the DataAttributes and so on). Therefore the mapping methods from [[VTL>>doc:sdmx:Glossary 2\.1.Validation and transformation language.WebHome]] to [[SDMX>>doc:sdmx:Glossary 2\.1.Statistical data and metadata exchange.WebHome]] provide only a general guidance for generating [[SDMX>>doc:sdmx:Glossary 2\.1.Statistical data and metadata exchange.WebHome]] definitions properly starting from the information available in [[VTL>>doc:sdmx:Glossary 2\.1.Validation and transformation language.WebHome]], independently of how the [[SDMX>>doc:sdmx:Glossary 2\.1.Statistical data and metadata exchange.WebHome]] definition it is actually generated (manually, automatically or part and part).
  === 12.3.2 General mapping of VTL and SDMX data structures ===
  This section makes reference to the [[VTL>>doc:sdmx:Glossary 2\.1.Validation and transformation language.WebHome]] "Model for data and their structure"{{footnote}}See the VTL 2.0 User Manual{{/footnote}} and the correspondent [[SDMX>>doc:sdmx:Glossary 2\.1.Statistical data and metadata exchange.WebHome]] "[[Data Structure Definition>>doc:sdmx:Glossary 2\.1.Data structure definition.WebHome]]"{{footnote}}See the SDMX Standards Section 2 – Information Model{{/footnote}}.
--The main type of [[artefact>>doc:sdmx:Glossary 2\.1.Artefact.WebHome]] that the [[VTL>>doc:sdmx:Glossary 2\.1.Validation and transformation language.WebHome]] can manipulate is the [[VTL>>doc:sdmx:Glossary 2\.1.Validation and transformation language.WebHome]] [[Data Set>>doc:sdmx:Glossary 2\.1.Data set.WebHome]], which in general is (% style="color:#e74c3c" %)mapped(%%) to the [[SDMX>>doc:sdmx:Glossary 2\.1.Statistical data and metadata exchange.WebHome]] [[Dataflow>>doc:sdmx:Glossary 2\.1.Dataflow.WebHome]]. This means that a [[VTL>>doc:sdmx:Glossary 2\.1.Validation and transformation language.WebHome]] Transformation, in the [[SDMX>>doc:sdmx:Glossary 2\.1.Statistical data and metadata exchange.WebHome]] context, expresses the algorithm for calculating a derived [[Dataflow>>doc:sdmx:Glossary 2\.1.Dataflow.WebHome]] starting from some already existing [[Dataflows>>doc:sdmx:Glossary 2\.1.Dataflow.WebHome]] (either collected or derived).{{footnote}}Besides the mapping between one SDMX Dataflow and one VTL Data Set, it is also possible to map distinct parts of a SDMX Dataflow to different VTL Data Set, as explained in a following paragraph.{{/footnote}}
++The main type of [[artefact>>doc:sdmx:Glossary 2\.1.Artefact.WebHome]] that the [[VTL>>doc:sdmx:Glossary 2\.1.Validation and transformation language.WebHome]] can manipulate is the [[VTL>>doc:sdmx:Glossary 2\.1.Validation and transformation language.WebHome]] [[Data Set>>doc:sdmx:Glossary 2\.1.Data set.WebHome]], which in general is mapped to the [[SDMX>>doc:sdmx:Glossary 2\.1.Statistical data and metadata exchange.WebHome]] [[Dataflow>>doc:sdmx:Glossary 2\.1.Dataflow.WebHome]]. This means that a [[VTL>>doc:sdmx:Glossary 2\.1.Validation and transformation language.WebHome]] Transformation, in the [[SDMX>>doc:sdmx:Glossary 2\.1.Statistical data and metadata exchange.WebHome]] context, expresses the algorithm for calculating a derived [[Dataflow>>doc:sdmx:Glossary 2\.1.Dataflow.WebHome]] starting from some already existing [[Dataflows>>doc:sdmx:Glossary 2\.1.Dataflow.WebHome]] (either collected or derived).{{footnote}}Besides the mapping between one SDMX Dataflow and one VTL Data Set, it is also possible to map distinct parts of a SDMX Dataflow to different VTL Data Set, as explained in a following paragraph.{{/footnote}}
  While the [[VTL>>doc:sdmx:Glossary 2\.1.Validation and transformation language.WebHome]] Transformations are defined in term of [[Dataflow>>doc:sdmx:Glossary 2\.1.Dataflow.WebHome]] definitions, they are assumed to be executed on instances of such [[Dataflows>>doc:sdmx:Glossary 2\.1.Dataflow.WebHome]], provided at runtime to the [[VTL>>doc:sdmx:Glossary 2\.1.Validation and transformation language.WebHome]] engine (the mechanism for identifying the instances to be processed are not part of the [[VTL>>doc:sdmx:Glossary 2\.1.Validation and transformation language.WebHome]] specifications and depend on the implementation of the [[VTL>>doc:sdmx:Glossary 2\.1.Validation and transformation language.WebHome]]-based systems). As already said, the [[SDMX>>doc:sdmx:Glossary 2\.1.Statistical data and metadata exchange.WebHome]] [[Datasets>>doc:sdmx:Glossary 2\.1.Data set.WebHome]] are instances of [[SDMX>>doc:sdmx:Glossary 2\.1.Statistical data and metadata exchange.WebHome]] [[Dataflows>>doc:sdmx:Glossary 2\.1.Dataflow.WebHome]], therefore a [[VTL>>doc:sdmx:Glossary 2\.1.Validation and transformation language.WebHome]] Transformation defined on some [[SDMX>>doc:sdmx:Glossary 2\.1.Statistical data and metadata exchange.WebHome]] [[Dataflows>>doc:sdmx:Glossary 2\.1.Dataflow.WebHome]] can be applied on some corresponding [[SDMX>>doc:sdmx:Glossary 2\.1.Statistical data and metadata exchange.WebHome]] [[Datasets>>doc:sdmx:Glossary 2\.1.Data set.WebHome]].
@@ -204,18 +204,18 @@
  Correspondingly, in the [[SDMX>>doc:sdmx:Glossary 2\.1.Statistical data and metadata exchange.WebHome]] implementation of the [[VTL>>doc:sdmx:Glossary 2\.1.Validation and transformation language.WebHome]], the [[VTL>>doc:sdmx:Glossary 2\.1.Validation and transformation language.WebHome]] Identifiers can be (optionally) distinguished in similar sub-classes (Simple Identifier, Time Identifier) even if such a distinction is not evidenced in the [[VTL>>doc:sdmx:Glossary 2\.1.Validation and transformation language.WebHome]] IM.
--The possible (% style="color:#e74c3c" %)mapping(%%) options are described in more detail in the following sections.
++The possible mapping options are described in more detail in the following sections.
  === 12.3.3 Mapping from SDMX to VTL data structures ===
  ==== 12.3.3.1 Basic Mapping ====
--The main (% style="color:#e74c3c" %)mapping(%%) method from [[SDMX>>doc:sdmx:Glossary 2\.1.Statistical data and metadata exchange.WebHome]] to [[VTL>>doc:sdmx:Glossary 2\.1.Validation and transformation language.WebHome]] is called **Basic **(% style="color:#e74c3c" %)mapping(%%). This is considered as the default (% style="color:#e74c3c" %)mapping(%%) method and is applied unless a different method is specified through the VtlMappingScheme and VtlDataflowMapping classes.
++The main mapping method from [[SDMX>>doc:sdmx:Glossary 2\.1.Statistical data and metadata exchange.WebHome]] to [[VTL>>doc:sdmx:Glossary 2\.1.Validation and transformation language.WebHome]] is called **Basic **mapping. This is considered as the default mapping method and is applied unless a different method is specified through the VtlMappingScheme and VtlDataflowMapping classes.
  When transforming **from [[SDMX>>doc:sdmx:Glossary 2\.1.Statistical data and metadata exchange.WebHome]] to [[VTL>>doc:sdmx:Glossary 2\.1.Validation and transformation language.WebHome]]**, this method consists in leaving the [[components>>doc:sdmx:Glossary 2\.1.Component.WebHome]] unchanged and maintaining their names and roles, according to the following table:
  (% style="width:468.294px" %)
--|(% style="width:196px" %)**[[SDMX>>doc:sdmx:Glossary 2\.1.Statistical data and metadata exchange.WebHome]]**|(% style="width:269px" %)**[[VTL>>doc:sdmx:Glossary 2\.1.Validation and transformation language.WebHome]]**
++|(% style="width:196px" %)**SDMX**|(% style="width:269px" %)**VTL**
  |(% style="width:196px" %)[[Dimension>>doc:sdmx:Glossary 2\.1.Dimension.WebHome]]|(% style="width:269px" %)(Simple) Identifier
  |(% style="width:196px" %)TimeDimension|(% style="width:269px" %)(Time) Identifier
  |(% style="width:196px" %)[[Measure>>doc:sdmx:Glossary 2\.1.Measure.WebHome]]|(% style="width:269px" %)[[Measure>>doc:sdmx:Glossary 2\.1.Measure.WebHome]]
@@ -223,33 +223,33 @@
  The [[SDMX>>doc:sdmx:Glossary 2\.1.Statistical data and metadata exchange.WebHome]] DataAttributes, in [[VTL>>doc:sdmx:Glossary 2\.1.Validation and transformation language.WebHome]] they are all considered "at data point / observation (% style="color:#e74c3c" %)level(%%)" (i.e. dependent on all the [[VTL>>doc:sdmx:Glossary 2\.1.Validation and transformation language.WebHome]] Identifiers), because [[VTL>>doc:sdmx:Glossary 2\.1.Validation and transformation language.WebHome]] does not have the [[SDMX>>doc:sdmx:Glossary 2\.1.Statistical data and metadata exchange.WebHome]] AttributeRelationships, which defines the construct to which the DataAttribute is related (e.g. observation, [[dimension>>doc:sdmx:Glossary 2\.1.Dimension.WebHome]] or set or group of [[dimensions>>doc:sdmx:Glossary 2\.1.Dimension.WebHome]], whole [[data set>>doc:sdmx:Glossary 2\.1.Data set.WebHome]]).
--With the Basic (% style="color:#e74c3c" %)mapping(%%), one [[SDMX>>doc:sdmx:Glossary 2\.1.Statistical data and metadata exchange.WebHome]] observation^^27^^ generates one [[VTL>>doc:sdmx:Glossary 2\.1.Validation and transformation language.WebHome]] data point.
++With the Basic mapping, one [[SDMX>>doc:sdmx:Glossary 2\.1.Statistical data and metadata exchange.WebHome]] observation^^27^^ generates one [[VTL>>doc:sdmx:Glossary 2\.1.Validation and transformation language.WebHome]] data point.
  ==== 12.3.3.2 Pivot Mapping ====
--An alternative (% style="color:#e74c3c" %)mapping(%%) method from [[SDMX>>doc:sdmx:Glossary 2\.1.Statistical data and metadata exchange.WebHome]] to [[VTL>>doc:sdmx:Glossary 2\.1.Validation and transformation language.WebHome]] is the **Pivot **(% style="color:#e74c3c" %)mapping(%%), which makes sense and is different from the Basic method only for the [[SDMX>>doc:sdmx:Glossary 2\.1.Statistical data and metadata exchange.WebHome]] data structures that contain a [[Dimension>>doc:sdmx:Glossary 2\.1.Dimension.WebHome]] that plays the role of [[measure>>doc:sdmx:Glossary 2\.1.Measure.WebHome]] [[dimension>>doc:sdmx:Glossary 2\.1.Dimension.WebHome]] (like in [[SDMX>>doc:sdmx:Glossary 2\.1.Statistical data and metadata exchange.WebHome]] 2.1) and just one [[Measure>>doc:sdmx:Glossary 2\.1.Measure.WebHome]]. Through this method, these structures can be (% style="color:#e74c3c" %)mapped(%%) to multimeasure [[VTL>>doc:sdmx:Glossary 2\.1.Validation and transformation language.WebHome]] data structures. Besides that, a user may choose to use any [[Dimension>>doc:sdmx:Glossary 2\.1.Dimension.WebHome]] acting as a list of [[Measures>>doc:sdmx:Glossary 2\.1.Measure.WebHome]] (e.g., a [[Dimension>>doc:sdmx:Glossary 2\.1.Dimension.WebHome]] with [[indicators>>doc:sdmx:Glossary 2\.1.Statistical indicator.WebHome]]), either by considering the “[[Measure>>doc:sdmx:Glossary 2\.1.Measure.WebHome]]” role of a [[Dimension>>doc:sdmx:Glossary 2\.1.Dimension.WebHome]], or at will using any coded [[Dimension>>doc:sdmx:Glossary 2\.1.Dimension.WebHome]]. Of course, in [[SDMX>>doc:sdmx:Glossary 2\.1.Statistical data and metadata exchange.WebHome]] 3.0, this can only work when only one [[Measure>>doc:sdmx:Glossary 2\.1.Measure.WebHome]] is defined in the [[DSD>>doc:sdmx:Glossary 2\.1.Data structure definition.WebHome]].
++An alternative mapping method from [[SDMX>>doc:sdmx:Glossary 2\.1.Statistical data and metadata exchange.WebHome]] to [[VTL>>doc:sdmx:Glossary 2\.1.Validation and transformation language.WebHome]] is the **Pivot **mapping, which makes sense and is different from the Basic method only for the [[SDMX>>doc:sdmx:Glossary 2\.1.Statistical data and metadata exchange.WebHome]] data structures that contain a [[Dimension>>doc:sdmx:Glossary 2\.1.Dimension.WebHome]] that plays the role of [[measure>>doc:sdmx:Glossary 2\.1.Measure.WebHome]] [[dimension>>doc:sdmx:Glossary 2\.1.Dimension.WebHome]] (like in [[SDMX>>doc:sdmx:Glossary 2\.1.Statistical data and metadata exchange.WebHome]] 2.1) and just one [[Measure>>doc:sdmx:Glossary 2\.1.Measure.WebHome]]. Through this method, these structures can be mapped to multimeasure [[VTL>>doc:sdmx:Glossary 2\.1.Validation and transformation language.WebHome]] data structures. Besides that, a user may choose to use any [[Dimension>>doc:sdmx:Glossary 2\.1.Dimension.WebHome]] acting as a list of [[Measures>>doc:sdmx:Glossary 2\.1.Measure.WebHome]] (e.g., a [[Dimension>>doc:sdmx:Glossary 2\.1.Dimension.WebHome]] with [[indicators>>doc:sdmx:Glossary 2\.1.Statistical indicator.WebHome]]), either by considering the “[[Measure>>doc:sdmx:Glossary 2\.1.Measure.WebHome]]” role of a [[Dimension>>doc:sdmx:Glossary 2\.1.Dimension.WebHome]], or at will using any coded [[Dimension>>doc:sdmx:Glossary 2\.1.Dimension.WebHome]]. Of course, in [[SDMX>>doc:sdmx:Glossary 2\.1.Statistical data and metadata exchange.WebHome]] 3.0, this can only work when only one [[Measure>>doc:sdmx:Glossary 2\.1.Measure.WebHome]] is defined in the [[DSD>>doc:sdmx:Glossary 2\.1.Data structure definition.WebHome]].
--In [[SDMX>>doc:sdmx:Glossary 2\.1.Statistical data and metadata exchange.WebHome]] 2.1 the MeasureDimension was a subclass of DimensionComponent like [[Dimension>>doc:sdmx:Glossary 2\.1.Dimension.WebHome]] and TimeDimension. In the current [[SDMX>>doc:sdmx:Glossary 2\.1.Statistical data and metadata exchange.WebHome]] (% style="color:#e74c3c" %)version(%%), this subclass does not exist anymore, however a [[Dimension>>doc:sdmx:Glossary 2\.1.Dimension.WebHome]] can have the role of [[measure>>doc:sdmx:Glossary 2\.1.Measure.WebHome]] [[dimension>>doc:sdmx:Glossary 2\.1.Dimension.WebHome]] (i.e. a [[Dimension>>doc:sdmx:Glossary 2\.1.Dimension.WebHome]] that contributes to the identification of the [[measures>>doc:sdmx:Glossary 2\.1.Measure.WebHome]]). In [[SDMX>>doc:sdmx:Glossary 2\.1.Statistical data and metadata exchange.WebHome]] 2.1 a DataStructure could have zero or one MeasureDimensions, in the current (% style="color:#e74c3c" %)version(%%) of the standard, from zero to many [[Dimension>>doc:sdmx:Glossary 2\.1.Dimension.WebHome]] may have the role of [[measure>>doc:sdmx:Glossary 2\.1.Measure.WebHome]] [[dimension>>doc:sdmx:Glossary 2\.1.Dimension.WebHome]]. Hereinafter a [[Dimension>>doc:sdmx:Glossary 2\.1.Dimension.WebHome]] that plays the role of [[measure>>doc:sdmx:Glossary 2\.1.Measure.WebHome]] [[dimension>>doc:sdmx:Glossary 2\.1.Dimension.WebHome]] is referenced for simplicity as “MeasureDimension“, i.e. maintaining the capital letters and the courier font even if the MeasureDimension is not anymore a class in the [[SDMX Information Model>>doc:sdmx:Glossary 2\.1.SDMX Information Model.WebHome]] of the current [[SDMX>>doc:sdmx:Glossary 2\.1.Statistical data and metadata exchange.WebHome]] (% style="color:#e74c3c" %)version(%%). For the sake of simplicity, the description below considers just one [[Dimension>>doc:sdmx:Glossary 2\.1.Dimension.WebHome]] having the role of MeasureDimension (i.e., the more simple and common case). Nevertheless, it maintains its validity also if in the DataStructure there are more [[dimension>>doc:sdmx:Glossary 2\.1.Dimension.WebHome]] with the role of MeasureDimensions: in this case what is said about the MeasureDimension must be applied to the combination of all the MeasureDimensions considered as a joint [[variable>>doc:sdmx:Glossary 2\.1.Statistical variable.WebHome]]{{footnote}}E.g., if in the data structure there exist 3 Dimensions C,D,E having the role of MeasureDimension, they should be considered as a joint MeasureDimension Z=(C,D,E); therefore when the description says “each possible value Cj of the MeasureDimension …” it means “each possible combination of values (Cj, Dk, Ew) of the joint MeasureDimension Z=(C,D,E)”.{{/footnote}}.
++In [[SDMX>>doc:sdmx:Glossary 2\.1.Statistical data and metadata exchange.WebHome]] 2.1 the MeasureDimension was a subclass of DimensionComponent like [[Dimension>>doc:sdmx:Glossary 2\.1.Dimension.WebHome]] and TimeDimension. In the current [[SDMX>>doc:sdmx:Glossary 2\.1.Statistical data and metadata exchange.WebHome]] version, this subclass does not exist anymore, however a [[Dimension>>doc:sdmx:Glossary 2\.1.Dimension.WebHome]] can have the role of [[measure>>doc:sdmx:Glossary 2\.1.Measure.WebHome]] [[dimension>>doc:sdmx:Glossary 2\.1.Dimension.WebHome]] (i.e. a [[Dimension>>doc:sdmx:Glossary 2\.1.Dimension.WebHome]] that contributes to the identification of the [[measures>>doc:sdmx:Glossary 2\.1.Measure.WebHome]]). In [[SDMX>>doc:sdmx:Glossary 2\.1.Statistical data and metadata exchange.WebHome]] 2.1 a DataStructure could have zero or one MeasureDimensions, in the current version of the standard, from zero to many [[Dimension>>doc:sdmx:Glossary 2\.1.Dimension.WebHome]] may have the role of [[measure>>doc:sdmx:Glossary 2\.1.Measure.WebHome]] [[dimension>>doc:sdmx:Glossary 2\.1.Dimension.WebHome]]. Hereinafter a [[Dimension>>doc:sdmx:Glossary 2\.1.Dimension.WebHome]] that plays the role of [[measure>>doc:sdmx:Glossary 2\.1.Measure.WebHome]] [[dimension>>doc:sdmx:Glossary 2\.1.Dimension.WebHome]] is referenced for simplicity as “MeasureDimension“, i.e. maintaining the capital letters and the courier font even if the MeasureDimension is not anymore a class in the [[SDMX Information Model>>doc:sdmx:Glossary 2\.1.SDMX Information Model.WebHome]] of the current [[SDMX>>doc:sdmx:Glossary 2\.1.Statistical data and metadata exchange.WebHome]] version. For the sake of simplicity, the description below considers just one [[Dimension>>doc:sdmx:Glossary 2\.1.Dimension.WebHome]] having the role of MeasureDimension (i.e., the more simple and common case). Nevertheless, it maintains its validity also if in the DataStructure there are more [[dimension>>doc:sdmx:Glossary 2\.1.Dimension.WebHome]] with the role of MeasureDimensions: in this case what is said about the MeasureDimension must be applied to the combination of all the MeasureDimensions considered as a joint [[variable>>doc:sdmx:Glossary 2\.1.Statistical variable.WebHome]]{{footnote}}E.g., if in the data structure there exist 3 Dimensions C,D,E having the role of MeasureDimension, they should be considered as a joint MeasureDimension Z=(C,D,E); therefore when the description says “each possible value Cj of the MeasureDimension …” it means “each possible combination of values (Cj, Dk, Ew) of the joint MeasureDimension Z=(C,D,E)”.{{/footnote}}.
  Among other things, the Pivot method provides also backward compatibility with the [[SDMX>>doc:sdmx:Glossary 2\.1.Statistical data and metadata exchange.WebHome]] 2.1 data structures that contained a MeasureDimension.
--If applied to [[SDMX>>doc:sdmx:Glossary 2\.1.Statistical data and metadata exchange.WebHome]] structures that do not contain any MeasureDimension, this method behaves like the Basic (% style="color:#e74c3c" %)mapping(%%) (see the previous paragraph).
++If applied to [[SDMX>>doc:sdmx:Glossary 2\.1.Statistical data and metadata exchange.WebHome]] structures that do not contain any MeasureDimension, this method behaves like the Basic mapping (see the previous paragraph).
--The [[SDMX>>doc:sdmx:Glossary 2\.1.Statistical data and metadata exchange.WebHome]] structures that contain a MeasureDimension are (% style="color:#e74c3c" %)mapped(%%) as described below (this (% style="color:#e74c3c" %)mapping(%%) is equivalent to a pivoting operation):
++The [[SDMX>>doc:sdmx:Glossary 2\.1.Statistical data and metadata exchange.WebHome]] structures that contain a MeasureDimension are mapped as described below (this mapping is equivalent to a pivoting operation):
  * A [[SDMX>>doc:sdmx:Glossary 2\.1.Statistical data and metadata exchange.WebHome]] simple [[dimension>>doc:sdmx:Glossary 2\.1.Dimension.WebHome]] becomes a [[VTL>>doc:sdmx:Glossary 2\.1.Validation and transformation language.WebHome]] (simple) identifier and a [[SDMX>>doc:sdmx:Glossary 2\.1.Statistical data and metadata exchange.WebHome]] TimeDimension becomes a [[VTL>>doc:sdmx:Glossary 2\.1.Validation and transformation language.WebHome]] (time) identifier;
--* Each possible [[Code>>doc:sdmx:Glossary 2\.1.Code.WebHome]] Cj of the [[SDMX>>doc:sdmx:Glossary 2\.1.Statistical data and metadata exchange.WebHome]] MeasureDimension is (% style="color:#e74c3c" %)mapped(%%) to a [[VTL>>doc:sdmx:Glossary 2\.1.Validation and transformation language.WebHome]] [[Measure>>doc:sdmx:Glossary 2\.1.Measure.WebHome]], having the same name as the [[SDMX>>doc:sdmx:Glossary 2\.1.Statistical data and metadata exchange.WebHome]] [[Code>>doc:sdmx:Glossary 2\.1.Code.WebHome]] (i.e. Cj); the [[VTL>>doc:sdmx:Glossary 2\.1.Validation and transformation language.WebHome]] [[Measure>>doc:sdmx:Glossary 2\.1.Measure.WebHome]] Cj is a new [[VTL>>doc:sdmx:Glossary 2\.1.Validation and transformation language.WebHome]] [[component>>doc:sdmx:Glossary 2\.1.Component.WebHome]] even if the [[SDMX>>doc:sdmx:Glossary 2\.1.Statistical data and metadata exchange.WebHome]] data structure has not such a [[Component>>doc:sdmx:Glossary 2\.1.Component.WebHome]];
--* The [[SDMX>>doc:sdmx:Glossary 2\.1.Statistical data and metadata exchange.WebHome]] MeasureDimension is not (% style="color:#e74c3c" %)mapped(%%) to [[VTL>>doc:sdmx:Glossary 2\.1.Validation and transformation language.WebHome]] (it disappears in the [[VTL>>doc:sdmx:Glossary 2\.1.Validation and transformation language.WebHome]] Data Structure);
--* The [[SDMX>>doc:sdmx:Glossary 2\.1.Statistical data and metadata exchange.WebHome]] [[Measure>>doc:sdmx:Glossary 2\.1.Measure.WebHome]] is not (% style="color:#e74c3c" %)mapped(%%) to [[VTL>>doc:sdmx:Glossary 2\.1.Validation and transformation language.WebHome]] as well (it disappears in the [[VTL>>doc:sdmx:Glossary 2\.1.Validation and transformation language.WebHome]] Data Structure);
--* An [[SDMX>>doc:sdmx:Glossary 2\.1.Statistical data and metadata exchange.WebHome]] DataAttribute is (% style="color:#e74c3c" %)mapped(%%) in different ways according to its AttributeRelationship:
--** If, according to the [[SDMX>>doc:sdmx:Glossary 2\.1.Statistical data and metadata exchange.WebHome]] AttributeRelationship, the values of the DataAttribute do not depend on the values of the MeasureDimension, the [[SDMX>>doc:sdmx:Glossary 2\.1.Statistical data and metadata exchange.WebHome]] DataAttribute becomes a [[VTL>>doc:sdmx:Glossary 2\.1.Validation and transformation language.WebHome]] [[Attribute>>doc:sdmx:Glossary 2\.1.Attribute.WebHome]] having the same name. This happens if the AttributeRelationship is not specified (i.e. the DataAttribute does not depend on any DimensionComponent and therefore is at [[data set>>doc:sdmx:Glossary 2\.1.Data set.WebHome]] (% style="color:#e74c3c" %)level(%%)), or if it refers to a set (or a group) of [[dimensions>>doc:sdmx:Glossary 2\.1.Dimension.WebHome]] which does not include the MeasureDimension;
--** Otherwise, if, according to the [[SDMX>>doc:sdmx:Glossary 2\.1.Statistical data and metadata exchange.WebHome]] AttributeRelationship, the values of the DataAttribute depend on the MeasureDimension, the [[SDMX>>doc:sdmx:Glossary 2\.1.Statistical data and metadata exchange.WebHome]] DataAttribute is (% style="color:#e74c3c" %)mapped(%%) to one [[VTL>>doc:sdmx:Glossary 2\.1.Validation and transformation language.WebHome]] [[Attribute>>doc:sdmx:Glossary 2\.1.Attribute.WebHome]] for each possible [[Code>>doc:sdmx:Glossary 2\.1.Code.WebHome]] of the [[SDMX>>doc:sdmx:Glossary 2\.1.Statistical data and metadata exchange.WebHome]] MeasureDimension. By default, the names of the [[VTL>>doc:sdmx:Glossary 2\.1.Validation and transformation language.WebHome]] [[Attributes>>doc:sdmx:Glossary 2\.1.Attribute.WebHome]] are obtained by concatenating the name of the [[SDMX>>doc:sdmx:Glossary 2\.1.Statistical data and metadata exchange.WebHome]] DataAttribute and the names of the correspondent [[Code>>doc:sdmx:Glossary 2\.1.Code.WebHome]] of the MeasureDimension separated by underscore. For example, if the [[SDMX>>doc:sdmx:Glossary 2\.1.Statistical data and metadata exchange.WebHome]] DataAttribute is named DA and the possible [[Codes>>doc:sdmx:Glossary 2\.1.Code.WebHome]] of the [[SDMX>>doc:sdmx:Glossary 2\.1.Statistical data and metadata exchange.WebHome]] MeasureDimension are named C1, C2, …, Cn, then the corresponding [[VTL>>doc:sdmx:Glossary 2\.1.Validation and transformation language.WebHome]] [[Attributes>>doc:sdmx:Glossary 2\.1.Attribute.WebHome]] will be named DA_C1, DA_C2, …, DA_Cn (if different names are desired, they can be achieved afterwards by renaming the [[Attributes>>doc:sdmx:Glossary 2\.1.Attribute.WebHome]] through [[VTL>>doc:sdmx:Glossary 2\.1.Validation and transformation language.WebHome]] operators).
--** Like in the Basic (% style="color:#e74c3c" %)mapping(%%), the resulting [[VTL>>doc:sdmx:Glossary 2\.1.Validation and transformation language.WebHome]] [[Attributes>>doc:sdmx:Glossary 2\.1.Attribute.WebHome]] are considered as dependent on all the [[VTL>>doc:sdmx:Glossary 2\.1.Validation and transformation language.WebHome]] identifiers (i.e. "at data point / observation (% style="color:#e74c3c" %)level(%%)"), because [[VTL>>doc:sdmx:Glossary 2\.1.Validation and transformation language.WebHome]] does not have the [[SDMX>>doc:sdmx:Glossary 2\.1.Statistical data and metadata exchange.WebHome]] notion of [[Attribute Relationship>>doc:sdmx:Glossary 2\.1.Attribute relationship.WebHome]].
++* Each possible [[Code>>doc:sdmx:Glossary 2\.1.Code.WebHome]] Cj of the [[SDMX>>doc:sdmx:Glossary 2\.1.Statistical data and metadata exchange.WebHome]] MeasureDimension is mapped to a [[VTL>>doc:sdmx:Glossary 2\.1.Validation and transformation language.WebHome]] [[Measure>>doc:sdmx:Glossary 2\.1.Measure.WebHome]], having the same name as the [[SDMX>>doc:sdmx:Glossary 2\.1.Statistical data and metadata exchange.WebHome]] [[Code>>doc:sdmx:Glossary 2\.1.Code.WebHome]] (i.e. Cj); the [[VTL>>doc:sdmx:Glossary 2\.1.Validation and transformation language.WebHome]] [[Measure>>doc:sdmx:Glossary 2\.1.Measure.WebHome]] Cj is a new [[VTL>>doc:sdmx:Glossary 2\.1.Validation and transformation language.WebHome]] [[component>>doc:sdmx:Glossary 2\.1.Component.WebHome]] even if the [[SDMX>>doc:sdmx:Glossary 2\.1.Statistical data and metadata exchange.WebHome]] data structure has not such a [[Component>>doc:sdmx:Glossary 2\.1.Component.WebHome]];
++* The [[SDMX>>doc:sdmx:Glossary 2\.1.Statistical data and metadata exchange.WebHome]] MeasureDimension is not mapped to [[VTL>>doc:sdmx:Glossary 2\.1.Validation and transformation language.WebHome]] (it disappears in the [[VTL>>doc:sdmx:Glossary 2\.1.Validation and transformation language.WebHome]] Data Structure);
++* The [[SDMX>>doc:sdmx:Glossary 2\.1.Statistical data and metadata exchange.WebHome]] [[Measure>>doc:sdmx:Glossary 2\.1.Measure.WebHome]] is not mapped to [[VTL>>doc:sdmx:Glossary 2\.1.Validation and transformation language.WebHome]] as well (it disappears in the [[VTL>>doc:sdmx:Glossary 2\.1.Validation and transformation language.WebHome]] Data Structure);
++* An [[SDMX>>doc:sdmx:Glossary 2\.1.Statistical data and metadata exchange.WebHome]] DataAttribute is mapped in different ways according to its AttributeRelationship:
++** If, according to the [[SDMX>>doc:sdmx:Glossary 2\.1.Statistical data and metadata exchange.WebHome]] AttributeRelationship, the values of the DataAttribute do not depend on the values of the MeasureDimension, the [[SDMX>>doc:sdmx:Glossary 2\.1.Statistical data and metadata exchange.WebHome]] DataAttribute becomes a [[VTL>>doc:sdmx:Glossary 2\.1.Validation and transformation language.WebHome]] [[Attribute>>doc:sdmx:Glossary 2\.1.Attribute.WebHome]] having the same name. This happens if the AttributeRelationship is not specified (i.e. the DataAttribute does not depend on any DimensionComponent and therefore is at [[data set>>doc:sdmx:Glossary 2\.1.Data set.WebHome]] level), or if it refers to a set (or a group) of [[dimensions>>doc:sdmx:Glossary 2\.1.Dimension.WebHome]] which does not include the MeasureDimension;
++** Otherwise, if, according to the [[SDMX>>doc:sdmx:Glossary 2\.1.Statistical data and metadata exchange.WebHome]] AttributeRelationship, the values of the DataAttribute depend on the MeasureDimension, the [[SDMX>>doc:sdmx:Glossary 2\.1.Statistical data and metadata exchange.WebHome]] DataAttribute is mapped to one [[VTL>>doc:sdmx:Glossary 2\.1.Validation and transformation language.WebHome]] [[Attribute>>doc:sdmx:Glossary 2\.1.Attribute.WebHome]] for each possible [[Code>>doc:sdmx:Glossary 2\.1.Code.WebHome]] of the [[SDMX>>doc:sdmx:Glossary 2\.1.Statistical data and metadata exchange.WebHome]] MeasureDimension. By default, the names of the [[VTL>>doc:sdmx:Glossary 2\.1.Validation and transformation language.WebHome]] [[Attributes>>doc:sdmx:Glossary 2\.1.Attribute.WebHome]] are obtained by concatenating the name of the [[SDMX>>doc:sdmx:Glossary 2\.1.Statistical data and metadata exchange.WebHome]] DataAttribute and the names of the correspondent [[Code>>doc:sdmx:Glossary 2\.1.Code.WebHome]] of the MeasureDimension separated by underscore. For example, if the [[SDMX>>doc:sdmx:Glossary 2\.1.Statistical data and metadata exchange.WebHome]] DataAttribute is named DA and the possible [[Codes>>doc:sdmx:Glossary 2\.1.Code.WebHome]] of the [[SDMX>>doc:sdmx:Glossary 2\.1.Statistical data and metadata exchange.WebHome]] MeasureDimension are named C1, C2, …, Cn, then the corresponding [[VTL>>doc:sdmx:Glossary 2\.1.Validation and transformation language.WebHome]] [[Attributes>>doc:sdmx:Glossary 2\.1.Attribute.WebHome]] will be named DA_C1, DA_C2, …, DA_Cn (if different names are desired, they can be achieved afterwards by renaming the [[Attributes>>doc:sdmx:Glossary 2\.1.Attribute.WebHome]] through [[VTL>>doc:sdmx:Glossary 2\.1.Validation and transformation language.WebHome]] operators).
++** Like in the Basic mapping, the resulting [[VTL>>doc:sdmx:Glossary 2\.1.Validation and transformation language.WebHome]] [[Attributes>>doc:sdmx:Glossary 2\.1.Attribute.WebHome]] are considered as dependent on all the [[VTL>>doc:sdmx:Glossary 2\.1.Validation and transformation language.WebHome]] identifiers (i.e. "at data point / observation level"), because [[VTL>>doc:sdmx:Glossary 2\.1.Validation and transformation language.WebHome]] does not have the [[SDMX>>doc:sdmx:Glossary 2\.1.Statistical data and metadata exchange.WebHome]] notion of [[Attribute Relationship>>doc:sdmx:Glossary 2\.1.Attribute relationship.WebHome]].
--The summary (% style="color:#e74c3c" %)mapping(%%) table of the "pivot" (% style="color:#e74c3c" %)mapping(%%) from [[SDMX>>doc:sdmx:Glossary 2\.1.Statistical data and metadata exchange.WebHome]] to [[VTL>>doc:sdmx:Glossary 2\.1.Validation and transformation language.WebHome]] for the [[SDMX>>doc:sdmx:Glossary 2\.1.Statistical data and metadata exchange.WebHome]] data structures that contain a MeasureDimension is the following:
++The summary mapping table of the "pivot" mapping from [[SDMX>>doc:sdmx:Glossary 2\.1.Statistical data and metadata exchange.WebHome]] to [[VTL>>doc:sdmx:Glossary 2\.1.Validation and transformation language.WebHome]] for the [[SDMX>>doc:sdmx:Glossary 2\.1.Statistical data and metadata exchange.WebHome]] data structures that contain a MeasureDimension is the following:
  (% style="width:739.294px" %)
--|(% style="width:335px" %)**[[SDMX>>doc:sdmx:Glossary 2\.1.Statistical data and metadata exchange.WebHome]]**|(% style="width:400px" %)**[[VTL>>doc:sdmx:Glossary 2\.1.Validation and transformation language.WebHome]]**
++|(% style="width:335px" %)**SDMX**|(% style="width:400px" %)**VTL**
  |(% style="width:335px" %)[[Dimension>>doc:sdmx:Glossary 2\.1.Dimension.WebHome]]|(% style="width:400px" %)(Simple) Identifier
  |(% style="width:335px" %)TimeDimension|(% style="width:400px" %)(Time) Identifier
  |(% style="width:335px" %)MeasureDimension & one [[Measure>>doc:sdmx:Glossary 2\.1.Measure.WebHome]]|(% style="width:400px" %)One [[Measure>>doc:sdmx:Glossary 2\.1.Measure.WebHome]] for each [[Code>>doc:sdmx:Glossary 2\.1.Code.WebHome]] of the [[SDMX>>doc:sdmx:Glossary 2\.1.Statistical data and metadata exchange.WebHome]] MeasureDimension
@@ -259,9 +259,9 @@
  [[SDMX>>doc:sdmx:Glossary 2\.1.Statistical data and metadata exchange.WebHome]] MeasureDimension
  )))
--Using this (% style="color:#e74c3c" %)mapping(%%) method, the [[components>>doc:sdmx:Glossary 2\.1.Component.WebHome]] of the data structure can change in the conversion from [[SDMX>>doc:sdmx:Glossary 2\.1.Statistical data and metadata exchange.WebHome]] to [[VTL>>doc:sdmx:Glossary 2\.1.Validation and transformation language.WebHome]] and it must be taken into account that the [[VTL>>doc:sdmx:Glossary 2\.1.Validation and transformation language.WebHome]] statements can reference only the [[components>>doc:sdmx:Glossary 2\.1.Component.WebHome]] of the resulting [[VTL>>doc:sdmx:Glossary 2\.1.Validation and transformation language.WebHome]] data structure.
++Using this mapping method, the [[components>>doc:sdmx:Glossary 2\.1.Component.WebHome]] of the data structure can change in the conversion from [[SDMX>>doc:sdmx:Glossary 2\.1.Statistical data and metadata exchange.WebHome]] to [[VTL>>doc:sdmx:Glossary 2\.1.Validation and transformation language.WebHome]] and it must be taken into account that the [[VTL>>doc:sdmx:Glossary 2\.1.Validation and transformation language.WebHome]] statements can reference only the [[components>>doc:sdmx:Glossary 2\.1.Component.WebHome]] of the resulting [[VTL>>doc:sdmx:Glossary 2\.1.Validation and transformation language.WebHome]] data structure.
--At observation / data point (% style="color:#e74c3c" %)level(%%), calling Cj (j=1, … n) the j^^th^^ [[Code>>doc:sdmx:Glossary 2\.1.Code.WebHome]] of the MeasureDimension:
++At observation / data point level, calling Cj (j=1, … n) the j^^th^^ [[Code>>doc:sdmx:Glossary 2\.1.Code.WebHome]] of the MeasureDimension:
  * The set of [[SDMX>>doc:sdmx:Glossary 2\.1.Statistical data and metadata exchange.WebHome]] observations having the same values for all the [[Dimensions>>doc:sdmx:Glossary 2\.1.Dimension.WebHome]] except than the MeasureDimension become one multi-[[measure>>doc:sdmx:Glossary 2\.1.Measure.WebHome]] [[VTL>>doc:sdmx:Glossary 2\.1.Validation and transformation language.WebHome]] Data Point, having one [[Measure>>doc:sdmx:Glossary 2\.1.Measure.WebHome]] for each [[Code>>doc:sdmx:Glossary 2\.1.Code.WebHome]] Cj of the [[SDMX>>doc:sdmx:Glossary 2\.1.Statistical data and metadata exchange.WebHome]] MeasureDimension;
  * The values of the [[SDMX>>doc:sdmx:Glossary 2\.1.Statistical data and metadata exchange.WebHome]] simple [[Dimensions>>doc:sdmx:Glossary 2\.1.Dimension.WebHome]], TimeDimension and DataAttributes not depending on the MeasureDimension (these [[components>>doc:sdmx:Glossary 2\.1.Component.WebHome]] by definition have always the same values for all the observations of the set above) become the values of the corresponding [[VTL>>doc:sdmx:Glossary 2\.1.Validation and transformation language.WebHome]] (simple) Identifiers, (time) Identifier and [[Attributes>>doc:sdmx:Glossary 2\.1.Attribute.WebHome]].
@@ -274,22 +274,22 @@
  The Basic_A2M and Pivot_A2M behaves respectively like the Basic and Pivot methods, except that the final [[VTL>>doc:sdmx:Glossary 2\.1.Validation and transformation language.WebHome]] [[components>>doc:sdmx:Glossary 2\.1.Component.WebHome]], which according to the Basic and Pivot methods would have had the role of [[Attribute>>doc:sdmx:Glossary 2\.1.Attribute.WebHome]], assume instead the role of [[Measure>>doc:sdmx:Glossary 2\.1.Measure.WebHome]].
--Proper [[VTL>>doc:sdmx:Glossary 2\.1.Validation and transformation language.WebHome]] features allow changing the role of specific [[attributes>>doc:sdmx:Glossary 2\.1.Attribute.WebHome]] even after the [[SDMX>>doc:sdmx:Glossary 2\.1.Statistical data and metadata exchange.WebHome]] to [[VTL>>doc:sdmx:Glossary 2\.1.Validation and transformation language.WebHome]] (% style="color:#e74c3c" %)mapping(%%): they can be useful when only some of the DataAttributes need to be managed as [[VTL>>doc:sdmx:Glossary 2\.1.Validation and transformation language.WebHome]] [[Measures>>doc:sdmx:Glossary 2\.1.Measure.WebHome]].
++Proper [[VTL>>doc:sdmx:Glossary 2\.1.Validation and transformation language.WebHome]] features allow changing the role of specific [[attributes>>doc:sdmx:Glossary 2\.1.Attribute.WebHome]] even after the [[SDMX>>doc:sdmx:Glossary 2\.1.Statistical data and metadata exchange.WebHome]] to [[VTL>>doc:sdmx:Glossary 2\.1.Validation and transformation language.WebHome]] mapping: they can be useful when only some of the DataAttributes need to be managed as [[VTL>>doc:sdmx:Glossary 2\.1.Validation and transformation language.WebHome]] [[Measures>>doc:sdmx:Glossary 2\.1.Measure.WebHome]].
  === 12.3.4 Mapping from VTL to SDMX data structures ===
  ==== 12.3.4.1 Basic Mapping ====
--The main (% style="color:#e74c3c" %)mapping(%%) method **from [[VTL>>doc:sdmx:Glossary 2\.1.Validation and transformation language.WebHome]] to [[SDMX>>doc:sdmx:Glossary 2\.1.Statistical data and metadata exchange.WebHome]]** is called **Basic **(% style="color:#e74c3c" %)mapping(%%) as well.
++The main mapping method **from [[VTL>>doc:sdmx:Glossary 2\.1.Validation and transformation language.WebHome]] to [[SDMX>>doc:sdmx:Glossary 2\.1.Statistical data and metadata exchange.WebHome]]** is called **Basic **mapping as well.
  This is considered as the default (% style="color:#e74c3c" %)mapping(%%) method and is applied unless a different method is specified through the VtlMappingScheme and VtlDataflowMapping classes.
--The method consists in leaving the [[components>>doc:sdmx:Glossary 2\.1.Component.WebHome]] unchanged and maintaining their names and roles in [[SDMX>>doc:sdmx:Glossary 2\.1.Statistical data and metadata exchange.WebHome]], according to the following (% style="color:#e74c3c" %)mapping(%%) table, which is the same as the basic (% style="color:#e74c3c" %)mapping(%%) from [[SDMX>>doc:sdmx:Glossary 2\.1.Statistical data and metadata exchange.WebHome]] to [[VTL>>doc:sdmx:Glossary 2\.1.Validation and transformation language.WebHome]], only seen in the opposite direction.
++The method consists in leaving the [[components>>doc:sdmx:Glossary 2\.1.Component.WebHome]] unchanged and maintaining their names and roles in [[SDMX>>doc:sdmx:Glossary 2\.1.Statistical data and metadata exchange.WebHome]], according to the following mapping table, which is the same as the basic mapping from [[SDMX>>doc:sdmx:Glossary 2\.1.Statistical data and metadata exchange.WebHome]] to [[VTL>>doc:sdmx:Glossary 2\.1.Validation and transformation language.WebHome]], only seen in the opposite direction.
--(% style="color:#e74c3c" %)Mapping(%%) table:
++Mapping table:
  (% style="width:470.294px" %)
--|(% style="width:262px" %)**[[VTL>>doc:sdmx:Glossary 2\.1.Validation and transformation language.WebHome]]**|(% style="width:205px" %)**[[SDMX>>doc:sdmx:Glossary 2\.1.Statistical data and metadata exchange.WebHome]]**
++|(% style="width:262px" %)**VTL**|(% style="width:205px" %)**SDMX**
  |(% style="width:262px" %)(Simple) Identifier|(% style="width:205px" %)[[Dimension>>doc:sdmx:Glossary 2\.1.Dimension.WebHome]]
  |(% style="width:262px" %)(Time) Identifier|(% style="width:205px" %)TimeDimension
  |(% style="width:262px" %)[[Measure>>doc:sdmx:Glossary 2\.1.Measure.WebHome]]|(% style="width:205px" %)[[Measure>>doc:sdmx:Glossary 2\.1.Measure.WebHome]]
@@ -297,38 +297,38 @@
  If the distinction between simple identifier and time identifier is not maintained in the [[VTL>>doc:sdmx:Glossary 2\.1.Validation and transformation language.WebHome]] environment, the [[classification>>doc:sdmx:Glossary 2\.1.Statistical Classification.WebHome]] between [[Dimension>>doc:sdmx:Glossary 2\.1.Dimension.WebHome]] and TimeDimension exists only in [[SDMX>>doc:sdmx:Glossary 2\.1.Statistical data and metadata exchange.WebHome]], as declared in the relevant DataStructureDefinition.
--Regarding the [[Attributes>>doc:sdmx:Glossary 2\.1.Attribute.WebHome]], because [[VTL>>doc:sdmx:Glossary 2\.1.Validation and transformation language.WebHome]] considers all of them "at observation (% style="color:#e74c3c" %)level(%%)", the corresponding [[SDMX>>doc:sdmx:Glossary 2\.1.Statistical data and metadata exchange.WebHome]] DataAttributes should be put "at observation (% style="color:#e74c3c" %)level(%%)" as well, unless some different information about their AttributeRelationship is otherwise available.
++Regarding the [[Attributes>>doc:sdmx:Glossary 2\.1.Attribute.WebHome]], because [[VTL>>doc:sdmx:Glossary 2\.1.Validation and transformation language.WebHome]] considers all of them "at observation level", the corresponding [[SDMX>>doc:sdmx:Glossary 2\.1.Statistical data and metadata exchange.WebHome]] DataAttributes should be put "at observation level" as well, unless some different information about their AttributeRelationship is otherwise available.
--Note that the basic mappings in the two directions (from [[SDMX>>doc:sdmx:Glossary 2\.1.Statistical data and metadata exchange.WebHome]] to [[VTL>>doc:sdmx:Glossary 2\.1.Validation and transformation language.WebHome]] and vice-versa) are (almost completely) reversible. In fact, if a [[SDMX>>doc:sdmx:Glossary 2\.1.Statistical data and metadata exchange.WebHome]] structure is (% style="color:#e74c3c" %)mapped(%%) to a [[VTL>>doc:sdmx:Glossary 2\.1.Validation and transformation language.WebHome]] structure and then the latter is (% style="color:#e74c3c" %)mapped(%%) back to [[SDMX>>doc:sdmx:Glossary 2\.1.Statistical data and metadata exchange.WebHome]], the resulting data structure is like the original one (apart for the AttributeRelationship, that can be different if the original [[SDMX>>doc:sdmx:Glossary 2\.1.Statistical data and metadata exchange.WebHome]] structure contains DataAttributes that are not at observation (% style="color:#e74c3c" %)level(%%)). In reverse order, if a [[VTL>>doc:sdmx:Glossary 2\.1.Validation and transformation language.WebHome]] structure is (% style="color:#e74c3c" %)mapped(%%) to [[SDMX>>doc:sdmx:Glossary 2\.1.Statistical data and metadata exchange.WebHome]] and then the latter is (% style="color:#e74c3c" %)mapped(%%) back to [[VTL>>doc:sdmx:Glossary 2\.1.Validation and transformation language.WebHome]], the original data structure is obtained.
++Note that the basic mappings in the two directions (from [[SDMX>>doc:sdmx:Glossary 2\.1.Statistical data and metadata exchange.WebHome]] to [[VTL>>doc:sdmx:Glossary 2\.1.Validation and transformation language.WebHome]] and vice-versa) are (almost completely) reversible. In fact, if a [[SDMX>>doc:sdmx:Glossary 2\.1.Statistical data and metadata exchange.WebHome]] structure is mapped to a [[VTL>>doc:sdmx:Glossary 2\.1.Validation and transformation language.WebHome]] structure and then the latter is mapped back to [[SDMX>>doc:sdmx:Glossary 2\.1.Statistical data and metadata exchange.WebHome]], the resulting data structure is like the original one (apart for the AttributeRelationship, that can be different if the original [[SDMX>>doc:sdmx:Glossary 2\.1.Statistical data and metadata exchange.WebHome]] structure contains DataAttributes that are not at observation level). In reverse order, if a [[VTL>>doc:sdmx:Glossary 2\.1.Validation and transformation language.WebHome]] structure is mapped to [[SDMX>>doc:sdmx:Glossary 2\.1.Statistical data and metadata exchange.WebHome]] and then the latter is mapped back to [[VTL>>doc:sdmx:Glossary 2\.1.Validation and transformation language.WebHome]], the original data structure is obtained.
  As said, the resulting [[SDMX>>doc:sdmx:Glossary 2\.1.Statistical data and metadata exchange.WebHome]] definitions must be compliant with the [[SDMX>>doc:sdmx:Glossary 2\.1.Statistical data and metadata exchange.WebHome]] consistency rules. For example, the [[SDMX>>doc:sdmx:Glossary 2\.1.Statistical data and metadata exchange.WebHome]] [[DSD>>doc:sdmx:Glossary 2\.1.Data structure definition.WebHome]] must have the AttributeRelationship for the DataAttributes, which does not exist in [[VTL>>doc:sdmx:Glossary 2\.1.Validation and transformation language.WebHome]].
  ==== 12.3.4.2 Unpivot Mapping ====
--An alternative (% style="color:#e74c3c" %)mapping(%%) method from [[VTL>>doc:sdmx:Glossary 2\.1.Validation and transformation language.WebHome]] to [[SDMX>>doc:sdmx:Glossary 2\.1.Statistical data and metadata exchange.WebHome]] is the **Unpivot **(% style="color:#e74c3c" %)mapping(%%).
++An alternative mapping method from [[VTL>>doc:sdmx:Glossary 2\.1.Validation and transformation language.WebHome]] to [[SDMX>>doc:sdmx:Glossary 2\.1.Statistical data and metadata exchange.WebHome]] is the **Unpivot **mapping.
--Although this (% style="color:#e74c3c" %)mapping(%%) method can be used in any case, it makes major sense in case the [[VTL>>doc:sdmx:Glossary 2\.1.Validation and transformation language.WebHome]] data structure has more than one [[measure>>doc:sdmx:Glossary 2\.1.Measure.WebHome]] [[component>>doc:sdmx:Glossary 2\.1.Component.WebHome]] (multi-[[measures>>doc:sdmx:Glossary 2\.1.Measure.WebHome]] [[VTL>>doc:sdmx:Glossary 2\.1.Validation and transformation language.WebHome]] structure). This is used to support the [[SDMX>>doc:sdmx:Glossary 2\.1.Statistical data and metadata exchange.WebHome]] 2.1 case of a MeasureDimension or any other [[Dimension>>doc:sdmx:Glossary 2\.1.Dimension.WebHome]] acting as a list of [[Measures>>doc:sdmx:Glossary 2\.1.Measure.WebHome]], under the assumptions explained in section “Pivot (% style="color:#e74c3c" %)Mapping(%%)”.
++Although this mapping method can be used in any case, it makes major sense in case the [[VTL>>doc:sdmx:Glossary 2\.1.Validation and transformation language.WebHome]] data structure has more than one [[measure>>doc:sdmx:Glossary 2\.1.Measure.WebHome]] [[component>>doc:sdmx:Glossary 2\.1.Component.WebHome]] (multi-[[measures>>doc:sdmx:Glossary 2\.1.Measure.WebHome]] [[VTL>>doc:sdmx:Glossary 2\.1.Validation and transformation language.WebHome]] structure). This is used to support the [[SDMX>>doc:sdmx:Glossary 2\.1.Statistical data and metadata exchange.WebHome]] 2.1 case of a MeasureDimension or any other [[Dimension>>doc:sdmx:Glossary 2\.1.Dimension.WebHome]] acting as a list of [[Measures>>doc:sdmx:Glossary 2\.1.Measure.WebHome]], under the assumptions explained in section “Pivot Mapping”.
  The multi-[[measures>>doc:sdmx:Glossary 2\.1.Measure.WebHome]] [[VTL>>doc:sdmx:Glossary 2\.1.Validation and transformation language.WebHome]] structures are converted to [[SDMX>>doc:sdmx:Glossary 2\.1.Statistical data and metadata exchange.WebHome]] [[Dataflows>>doc:sdmx:Glossary 2\.1.Dataflow.WebHome]] having an added MeasureDimension, which disambiguates the [[VTL>>doc:sdmx:Glossary 2\.1.Validation and transformation language.WebHome]] multiple [[Measures>>doc:sdmx:Glossary 2\.1.Measure.WebHome]], and a new [[Measure>>doc:sdmx:Glossary 2\.1.Measure.WebHome]] in place of the [[VTL>>doc:sdmx:Glossary 2\.1.Validation and transformation language.WebHome]] ones, containing the values of the [[VTL>>doc:sdmx:Glossary 2\.1.Validation and transformation language.WebHome]] [[Measures>>doc:sdmx:Glossary 2\.1.Measure.WebHome]].
--The **unpivot** (% style="color:#e74c3c" %)mapping(%%) behaves like follows:
++The **unpivot** mapping behaves like follows:
--* like in the basic (% style="color:#e74c3c" %)mapping(%%), a [[VTL>>doc:sdmx:Glossary 2\.1.Validation and transformation language.WebHome]] (simple) identifier becomes a [[SDMX>>doc:sdmx:Glossary 2\.1.Statistical data and metadata exchange.WebHome]] [[Dimension>>doc:sdmx:Glossary 2\.1.Dimension.WebHome]] and a [[VTL>>doc:sdmx:Glossary 2\.1.Validation and transformation language.WebHome]] (time) identifier becomes a [[SDMX>>doc:sdmx:Glossary 2\.1.Statistical data and metadata exchange.WebHome]] TimeDimension (as said, a [[measure>>doc:sdmx:Glossary 2\.1.Measure.WebHome]] identifier cannot exist in multi-[[measure>>doc:sdmx:Glossary 2\.1.Measure.WebHome]] [[VTL>>doc:sdmx:Glossary 2\.1.Validation and transformation language.WebHome]] structures);
++* like in the basic mapping, a [[VTL>>doc:sdmx:Glossary 2\.1.Validation and transformation language.WebHome]] (simple) identifier becomes a [[SDMX>>doc:sdmx:Glossary 2\.1.Statistical data and metadata exchange.WebHome]] [[Dimension>>doc:sdmx:Glossary 2\.1.Dimension.WebHome]] and a [[VTL>>doc:sdmx:Glossary 2\.1.Validation and transformation language.WebHome]] (time) identifier becomes a [[SDMX>>doc:sdmx:Glossary 2\.1.Statistical data and metadata exchange.WebHome]] TimeDimension (as said, a [[measure>>doc:sdmx:Glossary 2\.1.Measure.WebHome]] identifier cannot exist in multi-[[measure>>doc:sdmx:Glossary 2\.1.Measure.WebHome]] [[VTL>>doc:sdmx:Glossary 2\.1.Validation and transformation language.WebHome]] structures);
  * a MeasureDimension [[component>>doc:sdmx:Glossary 2\.1.Component.WebHome]] called "measure_name" is added to the [[SDMX>>doc:sdmx:Glossary 2\.1.Statistical data and metadata exchange.WebHome]] DataStructure;
  * a [[Measure>>doc:sdmx:Glossary 2\.1.Measure.WebHome]] [[component>>doc:sdmx:Glossary 2\.1.Component.WebHome]] called "obs_value" is added to the [[SDMX>>doc:sdmx:Glossary 2\.1.Statistical data and metadata exchange.WebHome]] DataStructure;
--* each [[VTL>>doc:sdmx:Glossary 2\.1.Validation and transformation language.WebHome]] [[Measure>>doc:sdmx:Glossary 2\.1.Measure.WebHome]] is (% style="color:#e74c3c" %)mapped(%%) to a [[Code>>doc:sdmx:Glossary 2\.1.Code.WebHome]] of the [[SDMX>>doc:sdmx:Glossary 2\.1.Statistical data and metadata exchange.WebHome]] MeasureDimension having the same name as the [[VTL>>doc:sdmx:Glossary 2\.1.Validation and transformation language.WebHome]] [[Measure>>doc:sdmx:Glossary 2\.1.Measure.WebHome]] (therefore all the [[VTL>>doc:sdmx:Glossary 2\.1.Validation and transformation language.WebHome]] [[Measure>>doc:sdmx:Glossary 2\.1.Measure.WebHome]] [[Components>>doc:sdmx:Glossary 2\.1.Component.WebHome]] do not originate [[Components>>doc:sdmx:Glossary 2\.1.Component.WebHome]] in the [[SDMX>>doc:sdmx:Glossary 2\.1.Statistical data and metadata exchange.WebHome]] DataStructure);
++* each [[VTL>>doc:sdmx:Glossary 2\.1.Validation and transformation language.WebHome]] [[Measure>>doc:sdmx:Glossary 2\.1.Measure.WebHome]] is mapped to a [[Code>>doc:sdmx:Glossary 2\.1.Code.WebHome]] of the [[SDMX>>doc:sdmx:Glossary 2\.1.Statistical data and metadata exchange.WebHome]] MeasureDimension having the same name as the [[VTL>>doc:sdmx:Glossary 2\.1.Validation and transformation language.WebHome]] [[Measure>>doc:sdmx:Glossary 2\.1.Measure.WebHome]] (therefore all the [[VTL>>doc:sdmx:Glossary 2\.1.Validation and transformation language.WebHome]] [[Measure>>doc:sdmx:Glossary 2\.1.Measure.WebHome]] [[Components>>doc:sdmx:Glossary 2\.1.Component.WebHome]] do not originate [[Components>>doc:sdmx:Glossary 2\.1.Component.WebHome]] in the [[SDMX>>doc:sdmx:Glossary 2\.1.Statistical data and metadata exchange.WebHome]] DataStructure);
  * a [[VTL>>doc:sdmx:Glossary 2\.1.Validation and transformation language.WebHome]] [[Attribute>>doc:sdmx:Glossary 2\.1.Attribute.WebHome]] becomes a [[SDMX>>doc:sdmx:Glossary 2\.1.Statistical data and metadata exchange.WebHome]] DataAttribute having AttributeRelationship referred to all the [[SDMX>>doc:sdmx:Glossary 2\.1.Statistical data and metadata exchange.WebHome]] DimensionComponents including the TimeDimension and except the MeasureDimension.
--The summary (% style="color:#e74c3c" %)mapping(%%) table of the **unpivot** (% style="color:#e74c3c" %)mapping(%%) method is the following:
++The summary mapping table of the **unpivot** mapping method is the following:
  (% style="width:638.294px" %)
--|(% style="width:200px" %)**[[VTL>>doc:sdmx:Glossary 2\.1.Validation and transformation language.WebHome]]**|(% style="width:435px" %)**[[SDMX>>doc:sdmx:Glossary 2\.1.Statistical data and metadata exchange.WebHome]]**
++|(% style="width:200px" %)**VTL**|(% style="width:435px" %)**SDMX**
  |(% style="width:200px" %)(Simple) Identifier|(% style="width:435px" %)[[Dimension>>doc:sdmx:Glossary 2\.1.Dimension.WebHome]]
  |(% style="width:200px" %)(Time) Identifier|(% style="width:435px" %)TimeDimension
  |(% style="width:200px" %)All [[Measure>>doc:sdmx:Glossary 2\.1.Measure.WebHome]] [[Components>>doc:sdmx:Glossary 2\.1.Component.WebHome]]|(% style="width:435px" %)MeasureDimension (having one [[Code>>doc:sdmx:Glossary 2\.1.Code.WebHome]] for each [[VTL>>doc:sdmx:Glossary 2\.1.Validation and transformation language.WebHome]] [[measure>>doc:sdmx:Glossary 2\.1.Measure.WebHome]] [[component>>doc:sdmx:Glossary 2\.1.Component.WebHome]]) & one [[Measure>>doc:sdmx:Glossary 2\.1.Measure.WebHome]]
  |(% style="width:200px" %)[[Attribute>>doc:sdmx:Glossary 2\.1.Attribute.WebHome]]|(% style="width:435px" %)DataAttribute depending on all [[SDMX>>doc:sdmx:Glossary 2\.1.Statistical data and metadata exchange.WebHome]] [[Dimensions>>doc:sdmx:Glossary 2\.1.Dimension.WebHome]] including the TimeDimension and except the MeasureDimension
--At observation / data point (% style="color:#e74c3c" %)level(%%):
++At observation / data point level:
  * a multi-[[measure>>doc:sdmx:Glossary 2\.1.Measure.WebHome]] [[VTL>>doc:sdmx:Glossary 2\.1.Validation and transformation language.WebHome]] Data Point becomes a set of [[SDMX>>doc:sdmx:Glossary 2\.1.Statistical data and metadata exchange.WebHome]] observations, one for each [[VTL>>doc:sdmx:Glossary 2\.1.Validation and transformation language.WebHome]] [[Measure>>doc:sdmx:Glossary 2\.1.Measure.WebHome]];
  * the values of the [[VTL>>doc:sdmx:Glossary 2\.1.Validation and transformation language.WebHome]] Identifiers become the values of the corresponding [[SDMX>>doc:sdmx:Glossary 2\.1.Statistical data and metadata exchange.WebHome]] DimensionComponents, for all the observations of the set above;
@@ -338,18 +338,18 @@
  If desired, this method can be applied also to mono-[[measure>>doc:sdmx:Glossary 2\.1.Measure.WebHome]] [[VTL>>doc:sdmx:Glossary 2\.1.Validation and transformation language.WebHome]] structures, provided that none of the [[VTL>>doc:sdmx:Glossary 2\.1.Validation and transformation language.WebHome]] [[Components>>doc:sdmx:Glossary 2\.1.Component.WebHome]] has already the role of [[Measure>>doc:sdmx:Glossary 2\.1.Measure.WebHome]] Identifier. Like in the general case, a MeasureDimension [[component>>doc:sdmx:Glossary 2\.1.Component.WebHome]] called “measure_name” is added to the [[SDMX>>doc:sdmx:Glossary 2\.1.Statistical data and metadata exchange.WebHome]] DataStructure, in this case it has just one possible [[Code>>doc:sdmx:Glossary 2\.1.Code.WebHome]], corresponding to the name of the unique [[VTL>>doc:sdmx:Glossary 2\.1.Validation and transformation language.WebHome]] [[Measure>>doc:sdmx:Glossary 2\.1.Measure.WebHome]]. The original [[VTL>>doc:sdmx:Glossary 2\.1.Validation and transformation language.WebHome]] [[Measure>>doc:sdmx:Glossary 2\.1.Measure.WebHome]] would not become a [[Component>>doc:sdmx:Glossary 2\.1.Component.WebHome]] in the [[SDMX>>doc:sdmx:Glossary 2\.1.Statistical data and metadata exchange.WebHome]] data structure. The value of the [[VTL>>doc:sdmx:Glossary 2\.1.Validation and transformation language.WebHome]] [[Measure>>doc:sdmx:Glossary 2\.1.Measure.WebHome]] would be assigned to the unique [[SDMX>>doc:sdmx:Glossary 2\.1.Statistical data and metadata exchange.WebHome]] [[Measure>>doc:sdmx:Glossary 2\.1.Measure.WebHome]] called “obs_value”.
--In any case, the resulting [[SDMX>>doc:sdmx:Glossary 2\.1.Statistical data and metadata exchange.WebHome]] definitions must be compliant with the [[SDMX>>doc:sdmx:Glossary 2\.1.Statistical data and metadata exchange.WebHome]] consistency rules. For example, the possible [[Codes>>doc:sdmx:Glossary 2\.1.Code.WebHome]] of the [[SDMX>>doc:sdmx:Glossary 2\.1.Statistical data and metadata exchange.WebHome]] MeasureDimension need to be listed in a [[SDMX>>doc:sdmx:Glossary 2\.1.Statistical data and metadata exchange.WebHome]] [[Codelist>>doc:sdmx:Glossary 2\.1.Code list.WebHome]], with proper id, agency and (% style="color:#e74c3c" %)version(%%); moreover, the [[SDMX>>doc:sdmx:Glossary 2\.1.Statistical data and metadata exchange.WebHome]] [[DSD>>doc:sdmx:Glossary 2\.1.Data structure definition.WebHome]] must have the AttributeRelationship for the DataAttributes, which does not exist in [[VTL>>doc:sdmx:Glossary 2\.1.Validation and transformation language.WebHome]].
++In any case, the resulting [[SDMX>>doc:sdmx:Glossary 2\.1.Statistical data and metadata exchange.WebHome]] definitions must be compliant with the [[SDMX>>doc:sdmx:Glossary 2\.1.Statistical data and metadata exchange.WebHome]] consistency rules. For example, the possible [[Codes>>doc:sdmx:Glossary 2\.1.Code.WebHome]] of the [[SDMX>>doc:sdmx:Glossary 2\.1.Statistical data and metadata exchange.WebHome]] MeasureDimension need to be listed in a [[SDMX>>doc:sdmx:Glossary 2\.1.Statistical data and metadata exchange.WebHome]] [[Codelist>>doc:sdmx:Glossary 2\.1.Code list.WebHome]], with proper id, agency and [[version>>doc:sdmx:Glossary 2\.1.Version.WebHome]]; moreover, the [[SDMX>>doc:sdmx:Glossary 2\.1.Statistical data and metadata exchange.WebHome]] [[DSD>>doc:sdmx:Glossary 2\.1.Data structure definition.WebHome]] must have the AttributeRelationship for the DataAttributes, which does not exist in [[VTL>>doc:sdmx:Glossary 2\.1.Validation and transformation language.WebHome]].
  ==== 12.3.4.3 From VTL Measures to SDMX Data Attributes ====
--More than all for the multi-[[measure>>doc:sdmx:Glossary 2\.1.Measure.WebHome]] [[VTL>>doc:sdmx:Glossary 2\.1.Validation and transformation language.WebHome]] structures (having more than one [[Measure>>doc:sdmx:Glossary 2\.1.Measure.WebHome]] [[Component>>doc:sdmx:Glossary 2\.1.Component.WebHome]]), it may happen that the [[Measures>>doc:sdmx:Glossary 2\.1.Measure.WebHome]] of the [[VTL>>doc:sdmx:Glossary 2\.1.Validation and transformation language.WebHome]] Data Structure need to be managed as DataAttributes in [[SDMX>>doc:sdmx:Glossary 2\.1.Statistical data and metadata exchange.WebHome]]. Therefore, a third (% style="color:#e74c3c" %)mapping(%%) method consists in transforming some [[VTL>>doc:sdmx:Glossary 2\.1.Validation and transformation language.WebHome]] [[measures>>doc:sdmx:Glossary 2\.1.Measure.WebHome]] in a corresponding [[SDMX>>doc:sdmx:Glossary 2\.1.Statistical data and metadata exchange.WebHome]] [[Measures>>doc:sdmx:Glossary 2\.1.Measure.WebHome]] and all the other [[VTL>>doc:sdmx:Glossary 2\.1.Validation and transformation language.WebHome]] [[Measures>>doc:sdmx:Glossary 2\.1.Measure.WebHome]] in [[SDMX>>doc:sdmx:Glossary 2\.1.Statistical data and metadata exchange.WebHome]] DataAttributes. This method is called M2A (“M2A” stands for “[[Measures>>doc:sdmx:Glossary 2\.1.Measure.WebHome]] to DataAttributes”).
++More than all for the multi-[[measure>>doc:sdmx:Glossary 2\.1.Measure.WebHome]] [[VTL>>doc:sdmx:Glossary 2\.1.Validation and transformation language.WebHome]] structures (having more than one [[Measure>>doc:sdmx:Glossary 2\.1.Measure.WebHome]] [[Component>>doc:sdmx:Glossary 2\.1.Component.WebHome]]), it may happen that the [[Measures>>doc:sdmx:Glossary 2\.1.Measure.WebHome]] of the [[VTL>>doc:sdmx:Glossary 2\.1.Validation and transformation language.WebHome]] Data Structure need to be managed as DataAttributes in [[SDMX>>doc:sdmx:Glossary 2\.1.Statistical data and metadata exchange.WebHome]]. Therefore, a third mapping method consists in transforming some [[VTL>>doc:sdmx:Glossary 2\.1.Validation and transformation language.WebHome]] [[measures>>doc:sdmx:Glossary 2\.1.Measure.WebHome]] in a corresponding [[SDMX>>doc:sdmx:Glossary 2\.1.Statistical data and metadata exchange.WebHome]] [[Measures>>doc:sdmx:Glossary 2\.1.Measure.WebHome]] and all the other [[VTL>>doc:sdmx:Glossary 2\.1.Validation and transformation language.WebHome]] [[Measures>>doc:sdmx:Glossary 2\.1.Measure.WebHome]] in [[SDMX>>doc:sdmx:Glossary 2\.1.Statistical data and metadata exchange.WebHome]] DataAttributes. This method is called M2A (“M2A” stands for “[[Measures>>doc:sdmx:Glossary 2\.1.Measure.WebHome]] to DataAttributes”).
  All [[VTL>>doc:sdmx:Glossary 2\.1.Validation and transformation language.WebHome]] [[Measures>>doc:sdmx:Glossary 2\.1.Measure.WebHome]] maintain their names in [[SDMX>>doc:sdmx:Glossary 2\.1.Statistical data and metadata exchange.WebHome]]. The [[VTL>>doc:sdmx:Glossary 2\.1.Validation and transformation language.WebHome]] [[Measure>>doc:sdmx:Glossary 2\.1.Measure.WebHome]] [[Components>>doc:sdmx:Glossary 2\.1.Component.WebHome]] that become [[SDMX>>doc:sdmx:Glossary 2\.1.Statistical data and metadata exchange.WebHome]] DataAttributes are the ones declared as DataAttributes in the target [[SDMX>>doc:sdmx:Glossary 2\.1.Statistical data and metadata exchange.WebHome]] [[data structure definition>>doc:sdmx:Glossary 2\.1.Data structure definition.WebHome]].
--The (% style="color:#e74c3c" %)mapping(%%) table is the following:
++The mapping table is the following:
  (% style="width:467.294px" %)
--|(% style="width:214px" %)[[VTL>>doc:sdmx:Glossary 2\.1.Validation and transformation language.WebHome]]|(% style="width:250px" %)[[SDMX>>doc:sdmx:Glossary 2\.1.Statistical data and metadata exchange.WebHome]]
++|(% style="width:214px" %)VTL|(% style="width:250px" %)SDMX
  |(% style="width:214px" %)(Simple) Identifier|(% style="width:250px" %)[[Dimension>>doc:sdmx:Glossary 2\.1.Dimension.WebHome]]
  |(% style="width:214px" %)(Time) Identifier|(% style="width:250px" %)TimeDimension
  |(% style="width:214px" %)Some [[Measures>>doc:sdmx:Glossary 2\.1.Measure.WebHome]]|(% style="width:250px" %)[[Measure>>doc:sdmx:Glossary 2\.1.Measure.WebHome]]
@@ -360,25 +360,25 @@
  === 12.3.5 Declaration of the mapping methods between data structures ===
--In order to define and understand properly [[VTL>>doc:sdmx:Glossary 2\.1.Validation and transformation language.WebHome]] Transformations, the applied (% style="color:#e74c3c" %)mapping(%%) methods must be specified in the [[SDMX>>doc:sdmx:Glossary 2\.1.Statistical data and metadata exchange.WebHome]] [[structural metadata>>doc:sdmx:Glossary 2\.1.Structural metadata.WebHome]]. If the default (% style="color:#e74c3c" %)mapping(%%) method (Basic) is applied, no specification is needed.
++In order to define and understand properly [[VTL>>doc:sdmx:Glossary 2\.1.Validation and transformation language.WebHome]] Transformations, the applied mapping methods must be specified in the [[SDMX>>doc:sdmx:Glossary 2\.1.Statistical data and metadata exchange.WebHome]] [[structural metadata>>doc:sdmx:Glossary 2\.1.Structural metadata.WebHome]]. If the default mapping method (Basic) is applied, no specification is needed.
--A customized (% style="color:#e74c3c" %)mapping(%%) can be defined through the VtlMappingScheme and VtlDataflowMapping classes (see the section of the [[SDMX>>doc:sdmx:Glossary 2\.1.Statistical data and metadata exchange.WebHome]] IM relevant to the [[VTL>>doc:sdmx:Glossary 2\.1.Validation and transformation language.WebHome]]). A VtlDataflowMapping allows specifying the (% style="color:#e74c3c" %)mapping(%%) methods to be used for a specific [[dataflow>>doc:sdmx:Glossary 2\.1.Dataflow.WebHome]], both in the direction from [[SDMX>>doc:sdmx:Glossary 2\.1.Statistical data and metadata exchange.WebHome]] to [[VTL>>doc:sdmx:Glossary 2\.1.Validation and transformation language.WebHome]] (toVtlMappingMethod) and from [[VTL>>doc:sdmx:Glossary 2\.1.Validation and transformation language.WebHome]] to [[SDMX>>doc:sdmx:Glossary 2\.1.Statistical data and metadata exchange.WebHome]] (fromVtlMappingMethod); in fact a VtlDataflowMapping associates the structured URN that identifies a [[SDMX>>doc:sdmx:Glossary 2\.1.Statistical data and metadata exchange.WebHome]] [[Dataflow>>doc:sdmx:Glossary 2\.1.Dataflow.WebHome]] to its [[VTL>>doc:sdmx:Glossary 2\.1.Validation and transformation language.WebHome]] alias and its (% style="color:#e74c3c" %)mapping(%%) methods.
++A customized mapping can be defined through the VtlMappingScheme and VtlDataflowMapping classes (see the section of the [[SDMX>>doc:sdmx:Glossary 2\.1.Statistical data and metadata exchange.WebHome]] IM relevant to the [[VTL>>doc:sdmx:Glossary 2\.1.Validation and transformation language.WebHome]]). A VtlDataflowMapping allows specifying the mapping methods to be used for a specific [[dataflow>>doc:sdmx:Glossary 2\.1.Dataflow.WebHome]], both in the direction from [[SDMX>>doc:sdmx:Glossary 2\.1.Statistical data and metadata exchange.WebHome]] to [[VTL>>doc:sdmx:Glossary 2\.1.Validation and transformation language.WebHome]] (toVtlMappingMethod) and from [[VTL>>doc:sdmx:Glossary 2\.1.Validation and transformation language.WebHome]] to [[SDMX>>doc:sdmx:Glossary 2\.1.Statistical data and metadata exchange.WebHome]] (fromVtlMappingMethod); in fact a VtlDataflowMapping associates the structured URN that identifies a [[SDMX>>doc:sdmx:Glossary 2\.1.Statistical data and metadata exchange.WebHome]] [[Dataflow>>doc:sdmx:Glossary 2\.1.Dataflow.WebHome]] to its [[VTL>>doc:sdmx:Glossary 2\.1.Validation and transformation language.WebHome]] alias and its mapping methods.
--It is possible to specify the toVtlMappingMethod and fromVtlMappingMethod also for the conventional [[dataflow>>doc:sdmx:Glossary 2\.1.Dataflow.WebHome]] called "generic_dataflow": in this case the specified (% style="color:#e74c3c" %)mapping(%%) methods are intended to become the default ones, overriding the "Basic" methods. In turn, the toVtlMappingMethod and fromVtlMappingMethod declared for a specific [[Dataflow>>doc:sdmx:Glossary 2\.1.Dataflow.WebHome]] are intended to override the default ones for such a [[Dataflow>>doc:sdmx:Glossary 2\.1.Dataflow.WebHome]].
++It is possible to specify the toVtlMappingMethod and fromVtlMappingMethod also for the conventional [[dataflow>>doc:sdmx:Glossary 2\.1.Dataflow.WebHome]] called "generic_dataflow": in this case the specified mapping methods are intended to become the default ones, overriding the "Basic" methods. In turn, the toVtlMappingMethod and fromVtlMappingMethod declared for a specific [[Dataflow>>doc:sdmx:Glossary 2\.1.Dataflow.WebHome]] are intended to override the default ones for such a [[Dataflow>>doc:sdmx:Glossary 2\.1.Dataflow.WebHome]].
  The VtlMappingScheme is a container for zero or more VtlDataflowMapping (it may contain also mappings towards [[artefacts>>doc:sdmx:Glossary 2\.1.Artefact.WebHome]] other than [[dataflows>>doc:sdmx:Glossary 2\.1.Dataflow.WebHome]]).
  === 12.3.6 Mapping dataflow subsets to distinct VTL Data Sets ===
--Until now it has been assumed to (% style="color:#e74c3c" %)map(%%) one SMDX [[Dataflow>>doc:sdmx:Glossary 2\.1.Dataflow.WebHome]] to one [[VTL>>doc:sdmx:Glossary 2\.1.Validation and transformation language.WebHome]] [[Data Set>>doc:sdmx:Glossary 2\.1.Data set.WebHome]] and vice-versa. This (% style="color:#e74c3c" %)mapping(%%) one-to-one is not mandatory according to [[VTL>>doc:sdmx:Glossary 2\.1.Validation and transformation language.WebHome]] because a [[VTL>>doc:sdmx:Glossary 2\.1.Validation and transformation language.WebHome]] [[Data Set>>doc:sdmx:Glossary 2\.1.Data set.WebHome]] is meant to be a set of observations (data points) on a logical plane, having the same logical data structure and the same general meaning, independently of the possible physical [[representation>>doc:sdmx:Glossary 2\.1.Representation.WebHome]] or storage (see [[VTL>>doc:sdmx:Glossary 2\.1.Validation and transformation language.WebHome]] 2.0 User Manual page 24), therefore a [[SDMX>>doc:sdmx:Glossary 2\.1.Statistical data and metadata exchange.WebHome]] [[Dataflow>>doc:sdmx:Glossary 2\.1.Dataflow.WebHome]] can be seen either as a unique set of data observations (corresponding to one [[VTL>>doc:sdmx:Glossary 2\.1.Validation and transformation language.WebHome]] [[Data Set>>doc:sdmx:Glossary 2\.1.Data set.WebHome]]) or as the union of many sets of data observations (each one corresponding to a distinct [[VTL>>doc:sdmx:Glossary 2\.1.Validation and transformation language.WebHome]] [[Data Set>>doc:sdmx:Glossary 2\.1.Data set.WebHome]]).
++Until now it has been assumed to map one SMDX [[Dataflow>>doc:sdmx:Glossary 2\.1.Dataflow.WebHome]] to one [[VTL>>doc:sdmx:Glossary 2\.1.Validation and transformation language.WebHome]] [[Data Set>>doc:sdmx:Glossary 2\.1.Data set.WebHome]] and vice-versa. This mapping one-to-one is not mandatory according to [[VTL>>doc:sdmx:Glossary 2\.1.Validation and transformation language.WebHome]] because a [[VTL>>doc:sdmx:Glossary 2\.1.Validation and transformation language.WebHome]] [[Data Set>>doc:sdmx:Glossary 2\.1.Data set.WebHome]] is meant to be a set of observations (data points) on a logical plane, having the same logical data structure and the same general meaning, independently of the possible physical [[representation>>doc:sdmx:Glossary 2\.1.Representation.WebHome]] or storage (see [[VTL>>doc:sdmx:Glossary 2\.1.Validation and transformation language.WebHome]] 2.0 User Manual page 24), therefore a [[SDMX>>doc:sdmx:Glossary 2\.1.Statistical data and metadata exchange.WebHome]] [[Dataflow>>doc:sdmx:Glossary 2\.1.Dataflow.WebHome]] can be seen either as a unique set of data observations (corresponding to one [[VTL>>doc:sdmx:Glossary 2\.1.Validation and transformation language.WebHome]] [[Data Set>>doc:sdmx:Glossary 2\.1.Data set.WebHome]]) or as the union of many sets of data observations (each one corresponding to a distinct [[VTL>>doc:sdmx:Glossary 2\.1.Validation and transformation language.WebHome]] [[Data Set>>doc:sdmx:Glossary 2\.1.Data set.WebHome]]).
  As a matter of fact, in some cases it can be useful to define [[VTL>>doc:sdmx:Glossary 2\.1.Validation and transformation language.WebHome]] operations involving definite parts of a [[SDMX>>doc:sdmx:Glossary 2\.1.Statistical data and metadata exchange.WebHome]] [[Dataflow>>doc:sdmx:Glossary 2\.1.Dataflow.WebHome]] instead than the whole.{{footnote}}A typical example of this kind is the validation, and more in general the manipulation, of individual time series belonging to the same Dataflow, identifiable through the DimensionComponents of the Dataflow except the TimeDimension. The coding of these kind of operations might be simplified by mapping distinct time series (i.e. different parts of a SDMX Dataflow) to distinct VTL Data Sets.{{/footnote}}
--Therefore, in order to make the coding of [[VTL>>doc:sdmx:Glossary 2\.1.Validation and transformation language.WebHome]] operations simpler when applied on parts of [[SDMX>>doc:sdmx:Glossary 2\.1.Statistical data and metadata exchange.WebHome]] [[Dataflows>>doc:sdmx:Glossary 2\.1.Dataflow.WebHome]], it is allowed to (% style="color:#e74c3c" %)map(%%) distinct parts of a [[SDMX>>doc:sdmx:Glossary 2\.1.Statistical data and metadata exchange.WebHome]] [[Dataflow>>doc:sdmx:Glossary 2\.1.Dataflow.WebHome]] to distinct [[VTL>>doc:sdmx:Glossary 2\.1.Validation and transformation language.WebHome]] [[Data Sets>>doc:sdmx:Glossary 2\.1.Data set.WebHome]] according to the following rules and conventions. This kind of (% style="color:#e74c3c" %)mapping(%%) is possible both from [[SDMX>>doc:sdmx:Glossary 2\.1.Statistical data and metadata exchange.WebHome]] to [[VTL>>doc:sdmx:Glossary 2\.1.Validation and transformation language.WebHome]] and from [[VTL>>doc:sdmx:Glossary 2\.1.Validation and transformation language.WebHome]] to [[SDMX>>doc:sdmx:Glossary 2\.1.Statistical data and metadata exchange.WebHome]], as better explained below.{{footnote}}Please note that this kind of mapping is only an option at disposal of the definer of VTL Transformations; in fact it remains always possible to manipulate the needed parts of SDMX Dataflows by means of VTL operators (e.g. “sub”, “filter”, “calc”, “union” …), maintaining a mapping one-to-one between SDMX Dataflows and VTL Data Sets.{{/footnote}}
++Therefore, in order to make the coding of [[VTL>>doc:sdmx:Glossary 2\.1.Validation and transformation language.WebHome]] operations simpler when applied on parts of [[SDMX>>doc:sdmx:Glossary 2\.1.Statistical data and metadata exchange.WebHome]] [[Dataflows>>doc:sdmx:Glossary 2\.1.Dataflow.WebHome]], it is allowed to map distinct parts of a [[SDMX>>doc:sdmx:Glossary 2\.1.Statistical data and metadata exchange.WebHome]] [[Dataflow>>doc:sdmx:Glossary 2\.1.Dataflow.WebHome]] to distinct [[VTL>>doc:sdmx:Glossary 2\.1.Validation and transformation language.WebHome]] [[Data Sets>>doc:sdmx:Glossary 2\.1.Data set.WebHome]] according to the following rules and conventions. This kind of mapping is possible both from [[SDMX>>doc:sdmx:Glossary 2\.1.Statistical data and metadata exchange.WebHome]] to [[VTL>>doc:sdmx:Glossary 2\.1.Validation and transformation language.WebHome]] and from [[VTL>>doc:sdmx:Glossary 2\.1.Validation and transformation language.WebHome]] to [[SDMX>>doc:sdmx:Glossary 2\.1.Statistical data and metadata exchange.WebHome]], as better explained below.{{footnote}}Please note that this kind of mapping is only an option at disposal of the definer of VTL Transformations; in fact it remains always possible to manipulate the needed parts of SDMX Dataflows by means of VTL operators (e.g. “sub”, “filter”, “calc”, “union” …), maintaining a mapping one-to-one between SDMX Dataflows and VTL Data Sets.{{/footnote}}
--Given a [[SDMX>>doc:sdmx:Glossary 2\.1.Statistical data and metadata exchange.WebHome]] [[Dataflow>>doc:sdmx:Glossary 2\.1.Dataflow.WebHome]] and some predefined [[Dimensions>>doc:sdmx:Glossary 2\.1.Dimension.WebHome]] of its DataStructure, it is allowed to (% style="color:#e74c3c" %)map(%%) the subsets of observations that have the same combination of values for such [[Dimensions>>doc:sdmx:Glossary 2\.1.Dimension.WebHome]] to correspondent [[VTL>>doc:sdmx:Glossary 2\.1.Validation and transformation language.WebHome]] [[datasets>>doc:sdmx:Glossary 2\.1.Data set.WebHome]].
++Given a [[SDMX>>doc:sdmx:Glossary 2\.1.Statistical data and metadata exchange.WebHome]] [[Dataflow>>doc:sdmx:Glossary 2\.1.Dataflow.WebHome]] and some predefined [[Dimensions>>doc:sdmx:Glossary 2\.1.Dimension.WebHome]] of its DataStructure, it is allowed to map the subsets of observations that have the same combination of values for such [[Dimensions>>doc:sdmx:Glossary 2\.1.Dimension.WebHome]] to correspondent [[VTL>>doc:sdmx:Glossary 2\.1.Validation and transformation language.WebHome]] [[datasets>>doc:sdmx:Glossary 2\.1.Data set.WebHome]].
--For example, assuming that the [[SDMX>>doc:sdmx:Glossary 2\.1.Statistical data and metadata exchange.WebHome]] [[Dataflow>>doc:sdmx:Glossary 2\.1.Dataflow.WebHome]] DF1(1.0.0) has the [[Dimensions>>doc:sdmx:Glossary 2\.1.Dimension.WebHome]] [[INDICATOR>>doc:sdmx:Glossary 2\.1.Statistical indicator.WebHome]], TIME_PERIOD and COUNTRY, and that the user declares the [[Dimensions>>doc:sdmx:Glossary 2\.1.Dimension.WebHome]] [[INDICATOR>>doc:sdmx:Glossary 2\.1.Statistical indicator.WebHome]] and COUNTRY as basis for the (% style="color:#e74c3c" %)mapping(%%) (i.e. the (% style="color:#e74c3c" %)mapping(%%) [[dimensions>>doc:sdmx:Glossary 2\.1.Dimension.WebHome]]): the observations that have the same values for [[INDICATOR>>doc:sdmx:Glossary 2\.1.Statistical indicator.WebHome]] and COUNTRY would be (% style="color:#e74c3c" %)mapped(%%) to the same [[VTL>>doc:sdmx:Glossary 2\.1.Validation and transformation language.WebHome]] [[dataset>>doc:sdmx:Glossary 2\.1.Data set.WebHome]] (and vice-versa). In practice, this kind (% style="color:#e74c3c" %)mapping(%%) is obtained like follows:
++For example, assuming that the [[SDMX>>doc:sdmx:Glossary 2\.1.Statistical data and metadata exchange.WebHome]] [[Dataflow>>doc:sdmx:Glossary 2\.1.Dataflow.WebHome]] DF1(1.0.0) has the [[Dimensions>>doc:sdmx:Glossary 2\.1.Dimension.WebHome]] [[INDICATOR>>doc:sdmx:Glossary 2\.1.Statistical indicator.WebHome]], TIME_PERIOD and COUNTRY, and that the user declares the [[Dimensions>>doc:sdmx:Glossary 2\.1.Dimension.WebHome]] [[INDICATOR>>doc:sdmx:Glossary 2\.1.Statistical indicator.WebHome]] and COUNTRY as basis for the mapping (i.e. the mapping [[dimensions>>doc:sdmx:Glossary 2\.1.Dimension.WebHome]]): the observations that have the same values for [[INDICATOR>>doc:sdmx:Glossary 2\.1.Statistical indicator.WebHome]] and COUNTRY would be mapped to the same [[VTL>>doc:sdmx:Glossary 2\.1.Validation and transformation language.WebHome]] [[dataset>>doc:sdmx:Glossary 2\.1.Data set.WebHome]] (and vice-versa). In practice, this kind (% style="color:#e74c3c" %)mapping(%%) is obtained like follows:
  * For a given [[SDMX>>doc:sdmx:Glossary 2\.1.Statistical data and metadata exchange.WebHome]] [[Dataflow>>doc:sdmx:Glossary 2\.1.Dataflow.WebHome]], the user ([[VTL>>doc:sdmx:Glossary 2\.1.Validation and transformation language.WebHome]] definer) declares the DimensionComponents on which the (% style="color:#e74c3c" %)mapping(%%) will be based, in a given order.{{footnote}}This definition is made through the ToVtlSubspace and ToVtlSpaceKey classes and/or the FromVtlSuperspace and FromVtlSpaceKey classes, depending on the direction of the mapping (“key” means “dimension”). The mapping of Dataflow subsets can be applied independently in the two directions, also according to different Dimensions. When no Dimension is declared for a given direction, it is assumed that the option of mapping different parts of a SDMX Dataflow to different VTL Data Sets is not used.{{/footnote}} Following the example above, imagine that the user declares the [[Dimensions>>doc:sdmx:Glossary 2\.1.Dimension.WebHome]] [[INDICATOR>>doc:sdmx:Glossary 2\.1.Statistical indicator.WebHome]] and COUNTRY.
  * The [[VTL>>doc:sdmx:Glossary 2\.1.Validation and transformation language.WebHome]] [[Data Set>>doc:sdmx:Glossary 2\.1.Data set.WebHome]] is given a name using a special notation also called “ordered concatenation” and composed of the following parts: