Changes for page 12 Validation and Transformation Language (VTL)
Last modified by Helena K. on 2026/06/10 10:09
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... ... @@ -398,17 +398,17 @@ 398 398 399 399 In particular, this is the [[VTL>>doc:sdmx:Glossary 2\.1.Validation and transformation language.WebHome]] [[dataset>>doc:sdmx:Glossary 2\.1.Data set.WebHome]] that contains all the observations of the [[Dataflow>>doc:sdmx:Glossary 2\.1.Dataflow.WebHome]] DF(1.0.0) for which //[[INDICATOR>>doc:sdmx:Glossary 2\.1.Statistical indicator.WebHome]]// = POPULATION and //COUNTRY// = USA. 400 400 401 -Let us now analyse the different meaning of this kind of mapping in the two mapping directions, i.e. 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]]. 401 +Let us now analyse the different meaning of this kind of (% style="color:#e74c3c" %)mapping(%%) in the two (% style="color:#e74c3c" %)mapping(%%) directions, i.e. 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]]. 402 402 403 -As already said, the 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]] happens when the [[SDMX>>doc:sdmx:Glossary 2\.1.Statistical data and metadata exchange.WebHome]] [[dataflows>>doc:sdmx:Glossary 2\.1.Dataflow.WebHome]] are operand of [[VTL>>doc:sdmx:Glossary 2\.1.Validation and transformation language.WebHome]] Transformations, instead the mapping 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]] happens when the [[VTL>>doc:sdmx:Glossary 2\.1.Validation and transformation language.WebHome]] [[Data Sets>>doc:sdmx:Glossary 2\.1.Data set.WebHome]] that is result of Transformations{{footnote}}It should be remembered that, according to the VTL consistency rules, a given VTL dataset cannot be the result of more than one VTL Transformation.{{/footnote}} need to be treated as [[SDMX>>doc:sdmx:Glossary 2\.1.Statistical data and metadata exchange.WebHome]] objects. This kind of mapping can be applied independently in the two directions and the [[Dimensions>>doc:sdmx:Glossary 2\.1.Dimension.WebHome]] on which the mapping is based can be different in the two directions: these [[Dimensions>>doc:sdmx:Glossary 2\.1.Dimension.WebHome]] are defined in the ToVtlSpaceKey and in the FromVtlSpaceKey classes respectively. 403 +As already said, the (% 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]] happens when the [[SDMX>>doc:sdmx:Glossary 2\.1.Statistical data and metadata exchange.WebHome]] [[dataflows>>doc:sdmx:Glossary 2\.1.Dataflow.WebHome]] are operand of [[VTL>>doc:sdmx:Glossary 2\.1.Validation and transformation language.WebHome]] Transformations, instead the (% style="color:#e74c3c" %)mapping(%%) 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]] happens when the [[VTL>>doc:sdmx:Glossary 2\.1.Validation and transformation language.WebHome]] [[Data Sets>>doc:sdmx:Glossary 2\.1.Data set.WebHome]] that is result of Transformations{{footnote}}It should be remembered that, according to the VTL consistency rules, a given VTL dataset cannot be the result of more than one VTL Transformation.{{/footnote}} need to be treated as [[SDMX>>doc:sdmx:Glossary 2\.1.Statistical data and metadata exchange.WebHome]] objects. This kind of (% style="color:#e74c3c" %)mapping(%%) can be applied independently in the two directions and the [[Dimensions>>doc:sdmx:Glossary 2\.1.Dimension.WebHome]] on which the (% style="color:#e74c3c" %)mapping(%%) is based can be different in the two directions: these [[Dimensions>>doc:sdmx:Glossary 2\.1.Dimension.WebHome]] are defined in the ToVtlSpaceKey and in the FromVtlSpaceKey classes respectively. 404 404 405 -First, let us see what happens in the mapping 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]], i.e. when parts of a [[SDMX>>doc:sdmx:Glossary 2\.1.Statistical data and metadata exchange.WebHome]] [[Dataflow>>doc:sdmx:Glossary 2\.1.Dataflow.WebHome]] (e.g. DF1(1.0.0)) need to be mapped to distinct [[VTL>>doc:sdmx:Glossary 2\.1.Validation and transformation language.WebHome]] [[Data Sets>>doc:sdmx:Glossary 2\.1.Data set.WebHome]] that are operand of some [[VTL>>doc:sdmx:Glossary 2\.1.Validation and transformation language.WebHome]] Transformations. 405 +First, let us see what happens in the (% style="color:#e74c3c" %)mapping(%%) 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]], i.e. when parts of a [[SDMX>>doc:sdmx:Glossary 2\.1.Statistical data and metadata exchange.WebHome]] [[Dataflow>>doc:sdmx:Glossary 2\.1.Dataflow.WebHome]] (e.g. DF1(1.0.0)) need to be (% style="color:#e74c3c" %)mapped(%%) to distinct [[VTL>>doc:sdmx:Glossary 2\.1.Validation and transformation language.WebHome]] [[Data Sets>>doc:sdmx:Glossary 2\.1.Data set.WebHome]] that are operand of some [[VTL>>doc:sdmx:Glossary 2\.1.Validation and transformation language.WebHome]] Transformations. 406 406 407 407 As already said, each [[VTL>>doc:sdmx:Glossary 2\.1.Validation and transformation language.WebHome]] [[Data Set>>doc:sdmx:Glossary 2\.1.Data set.WebHome]] is assumed to contain all the observations of the 408 408 409 409 [[SDMX>>doc:sdmx:Glossary 2\.1.Statistical data and metadata exchange.WebHome]] [[Dataflow>>doc:sdmx:Glossary 2\.1.Dataflow.WebHome]] having [[INDICATOR>>doc:sdmx:Glossary 2\.1.Statistical indicator.WebHome]]=//INDICATORvalue //and COUNTRY=// COUNTRYvalue//. For example, the [[VTL>>doc:sdmx:Glossary 2\.1.Validation and transformation language.WebHome]] [[dataset>>doc:sdmx:Glossary 2\.1.Data set.WebHome]] ‘DF1(1.0.0)/POPULATION.USA’ would contain all the observations of DF1(1.0.0) having [[INDICATOR>>doc:sdmx:Glossary 2\.1.Statistical indicator.WebHome]] = POPULATION and COUNTRY = USA. 410 410 411 -In order to obtain the data structure of these [[VTL>>doc:sdmx:Glossary 2\.1.Validation and transformation language.WebHome]] [[Data Sets>>doc:sdmx:Glossary 2\.1.Data set.WebHome]] from the [[SDMX>>doc:sdmx:Glossary 2\.1.Statistical data and metadata exchange.WebHome]] one, it is assumed that the [[SDMX>>doc:sdmx:Glossary 2\.1.Statistical data and metadata exchange.WebHome]] DimensionComponents on which the mapping is based are dropped, i.e. not maintained in the [[VTL>>doc:sdmx:Glossary 2\.1.Validation and transformation language.WebHome]] data structure; this is possible because their values are fixed for each one of the invoked [[VTL>>doc:sdmx:Glossary 2\.1.Validation and transformation language.WebHome]] [[Data Sets>>doc:sdmx:Glossary 2\.1.Data set.WebHome]]{{footnote}}If these DimensionComponents would not be dropped, the various VTL Data Sets resulting from this kind of mapping would have non-matching values for the Identifiers corresponding to the mapping Dimensions (e.g. POPULATION and COUNTRY). As a consequence, taking into account that the typical binary VTL operations at dataset level (+, -, *, / and so on) are executed on the observations having matching values for the identifiers, it would not be possible to compose the resulting VTL datasets one another (e.g. it would not be possible to calculate the population ratio between USA and CANADA).{{/footnote}}. After that, the 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]] specified for the [[Dataflow>>doc:sdmx:Glossary 2\.1.Dataflow.WebHome]] DF1(1.0.0) is applied (i.e. basic, pivot …). 411 +In order to obtain the data structure of these [[VTL>>doc:sdmx:Glossary 2\.1.Validation and transformation language.WebHome]] [[Data Sets>>doc:sdmx:Glossary 2\.1.Data set.WebHome]] from the [[SDMX>>doc:sdmx:Glossary 2\.1.Statistical data and metadata exchange.WebHome]] one, it is assumed that the [[SDMX>>doc:sdmx:Glossary 2\.1.Statistical data and metadata exchange.WebHome]] DimensionComponents on which the (% style="color:#e74c3c" %)mapping(%%) is based are dropped, i.e. not maintained in the [[VTL>>doc:sdmx:Glossary 2\.1.Validation and transformation language.WebHome]] data structure; this is possible because their values are fixed for each one of the invoked [[VTL>>doc:sdmx:Glossary 2\.1.Validation and transformation language.WebHome]] [[Data Sets>>doc:sdmx:Glossary 2\.1.Data set.WebHome]]{{footnote}}If these DimensionComponents would not be dropped, the various VTL Data Sets resulting from this kind of mapping would have non-matching values for the Identifiers corresponding to the mapping Dimensions (e.g. POPULATION and COUNTRY). As a consequence, taking into account that the typical binary VTL operations at dataset level (+, -, *, / and so on) are executed on the observations having matching values for the identifiers, it would not be possible to compose the resulting VTL datasets one another (e.g. it would not be possible to calculate the population ratio between USA and CANADA).{{/footnote}}. After that, the (% 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]] specified for the [[Dataflow>>doc:sdmx:Glossary 2\.1.Dataflow.WebHome]] DF1(1.0.0) is applied (i.e. basic, pivot …). 412 412 413 413 In the example above, for all the [[datasets>>doc:sdmx:Glossary 2\.1.Data set.WebHome]] of the kind 414 414 ... ... @@ -424,9 +424,9 @@ 424 424 > 425 425 > … … … 426 426 427 -In fact the [[VTL>>doc:sdmx:Glossary 2\.1.Validation and transformation language.WebHome]] operator “sub” has exactly the same behaviour. Therefore, mapping different parts of a [[SDMX>>doc:sdmx:Glossary 2\.1.Statistical data and metadata exchange.WebHome]] [[Dataflow>>doc:sdmx:Glossary 2\.1.Dataflow.WebHome]] to different [[VTL>>doc:sdmx:Glossary 2\.1.Validation and transformation language.WebHome]] [[Data Sets>>doc:sdmx:Glossary 2\.1.Data set.WebHome]] 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]] through the ordered concatenation notation is equivalent to a proper use of the operator “**sub**” on such a [[Dataflow>>doc:sdmx:Glossary 2\.1.Dataflow.WebHome]].{{footnote}}In case the ordered concatenation notation is used, the VTL Transformation described above, e.g. ‘DF1(1.0)/POPULATION.USA’ := DF1(1.0) [ sub INDICATOR=“POPULATION”, COUNTRY=“USA”], is implicitly executed. In order to test the overall compliance of the VTL program to the VTL consistency rules, it has to be considered as part of the VTL program even if it is not explicitly coded.{{/footnote}} 427 +In fact the [[VTL>>doc:sdmx:Glossary 2\.1.Validation and transformation language.WebHome]] operator “sub” has exactly the same behaviour. Therefore, (% style="color:#e74c3c" %)mapping(%%) different parts of a [[SDMX>>doc:sdmx:Glossary 2\.1.Statistical data and metadata exchange.WebHome]] [[Dataflow>>doc:sdmx:Glossary 2\.1.Dataflow.WebHome]] to different [[VTL>>doc:sdmx:Glossary 2\.1.Validation and transformation language.WebHome]] [[Data Sets>>doc:sdmx:Glossary 2\.1.Data set.WebHome]] 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]] through the ordered concatenation notation is equivalent to a proper use of the operator “**sub**” on such a [[Dataflow>>doc:sdmx:Glossary 2\.1.Dataflow.WebHome]].{{footnote}}In case the ordered concatenation notation is used, the VTL Transformation described above, e.g. ‘DF1(1.0)/POPULATION.USA’ := DF1(1.0) [ sub INDICATOR=“POPULATION”, COUNTRY=“USA”], is implicitly executed. In order to test the overall compliance of the VTL program to the VTL consistency rules, it has to be considered as part of the VTL program even if it is not explicitly coded.{{/footnote}} 428 428 429 -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]] it is allowed to omit the value of one or more DimensionComponents on which the mapping is based, but maintaining all the separating dots (therefore it may happen to find two or more consecutive dots and dots in the beginning or in the end). The absence of value means that for the corresponding [[Dimension>>doc:sdmx:Glossary 2\.1.Dimension.WebHome]] all the values are kept and the [[Dimension>>doc:sdmx:Glossary 2\.1.Dimension.WebHome]] is not dropped. 429 +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]] it is allowed to omit the value of one or more DimensionComponents on which the (% style="color:#e74c3c" %)mapping(%%) is based, but maintaining all the separating dots (therefore it may happen to find two or more consecutive dots and dots in the beginning or in the end). The absence of value means that for the corresponding [[Dimension>>doc:sdmx:Glossary 2\.1.Dimension.WebHome]] all the values are kept and the [[Dimension>>doc:sdmx:Glossary 2\.1.Dimension.WebHome]] is not dropped. 430 430 431 431 For example, ‘DF(1.0.0)/POPULATION.’ (note the dot in the end of the name) is the [[VTL>>doc:sdmx:Glossary 2\.1.Validation and transformation language.WebHome]] [[dataset>>doc:sdmx:Glossary 2\.1.Data set.WebHome]] that contains all the observations of the [[Dataflow>>doc:sdmx:Glossary 2\.1.Dataflow.WebHome]] DF(1.0.0) for which //[[INDICATOR>>doc:sdmx:Glossary 2\.1.Statistical indicator.WebHome]]// = POPULATION and COUNTRY = any value. 432 432 ... ... @@ -439,9 +439,9 @@ 439 439 440 440 Heterogeneous invocations of the same [[Dataflow>>doc:sdmx:Glossary 2\.1.Dataflow.WebHome]] are allowed, i.e. omitting different [[Dimensions>>doc:sdmx:Glossary 2\.1.Dimension.WebHome]] in different invocations. 441 441 442 -Let us now analyse the mapping direction 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]]. 442 +Let us now analyse the (% style="color:#e74c3c" %)mapping(%%) direction 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]]. 443 443 444 -In this situation, distinct parts of a [[SDMX>>doc:sdmx:Glossary 2\.1.Statistical data and metadata exchange.WebHome]] [[Dataflow>>doc:sdmx:Glossary 2\.1.Dataflow.WebHome]] are calculated as distinct [[VTL>>doc:sdmx:Glossary 2\.1.Validation and transformation language.WebHome]] [[datasets>>doc:sdmx:Glossary 2\.1.Data set.WebHome]], under the [[constraint>>doc:sdmx:Glossary2\.1.Constraint.WebHome]]that they must have the same [[VTL>>doc:sdmx:Glossary 2\.1.Validation and transformation language.WebHome]] data structure.444 +In this situation, distinct parts of a [[SDMX>>doc:sdmx:Glossary 2\.1.Statistical data and metadata exchange.WebHome]] [[Dataflow>>doc:sdmx:Glossary 2\.1.Dataflow.WebHome]] are calculated as distinct [[VTL>>doc:sdmx:Glossary 2\.1.Validation and transformation language.WebHome]] [[datasets>>doc:sdmx:Glossary 2\.1.Data set.WebHome]], under the (% style="color:#e74c3c" %)constraint(%%) that they must have the same [[VTL>>doc:sdmx:Glossary 2\.1.Validation and transformation language.WebHome]] data structure. 445 445 446 446 For example, let us assume that the [[VTL>>doc:sdmx:Glossary 2\.1.Validation and transformation language.WebHome]] programmer wants to calculate the [[SDMX>>doc:sdmx:Glossary 2\.1.Statistical data and metadata exchange.WebHome]] [[Dataflow>>doc:sdmx:Glossary 2\.1.Dataflow.WebHome]] DF2(1.0.0) having the [[Dimensions>>doc:sdmx:Glossary 2\.1.Dimension.WebHome]] TIME_PERIOD, [[INDICATOR>>doc:sdmx:Glossary 2\.1.Statistical indicator.WebHome]], and COUNTRY and that such a programmer finds it convenient to calculate separately the parts of DF2(1.0.0) that have different combinations of values for [[INDICATOR>>doc:sdmx:Glossary 2\.1.Statistical indicator.WebHome]] and COUNTRY: 447 447 ... ... @@ -448,7 +448,7 @@ 448 448 * each part is calculated as a [[VTL>>doc:sdmx:Glossary 2\.1.Validation and transformation language.WebHome]] derived [[Data Set>>doc:sdmx:Glossary 2\.1.Data set.WebHome]], result of a dedicated [[VTL>>doc:sdmx:Glossary 2\.1.Validation and transformation language.WebHome]] Transformation;{{footnote}}If the whole DF2(1.0) is calculated by means of just one VTL Transformation, then the mapping between the SDMX Dataflow and the corresponding VTL dataset is one-to-one and this kind of mapping (one SDMX Dataflow to many VTL datasets) does not apply.{{/footnote}} 449 449 * the data structure of all these [[VTL>>doc:sdmx:Glossary 2\.1.Validation and transformation language.WebHome]] [[Data Sets>>doc:sdmx:Glossary 2\.1.Data set.WebHome]] has the TIME_PERIOD identifier and does not have the [[INDICATOR>>doc:sdmx:Glossary 2\.1.Statistical indicator.WebHome]] and COUNTRY identifiers.{{footnote}}This is possible as each VTL dataset corresponds to one particular combination of values of INDICATOR and COUNTRY.{{/footnote}} 450 450 451 -Under these hypothesis, such derived [[VTL>>doc:sdmx:Glossary 2\.1.Validation and transformation language.WebHome]] [[Data Sets>>doc:sdmx:Glossary 2\.1.Data set.WebHome]] can be mapped to DF2(1.0.0) by declaring the DimensionComponents [[INDICATOR>>doc:sdmx:Glossary 2\.1.Statistical indicator.WebHome]] and COUNTRY as (% style="color:#e74c3c" %)mapping(%%) [[dimensions>>doc:sdmx:Glossary 2\.1.Dimension.WebHome]]{{footnote}}The mapping dimensions are defined as FromVtlSpaceKeys of the FromVtlSuperSpace of the VtlDataflowMapping relevant to DF2(1.0).{{/footnote}}. 451 +Under these hypothesis, such derived [[VTL>>doc:sdmx:Glossary 2\.1.Validation and transformation language.WebHome]] [[Data Sets>>doc:sdmx:Glossary 2\.1.Data set.WebHome]] can be (% style="color:#e74c3c" %)mapped(%%) to DF2(1.0.0) by declaring the DimensionComponents [[INDICATOR>>doc:sdmx:Glossary 2\.1.Statistical indicator.WebHome]] and COUNTRY as (% style="color:#e74c3c" %)mapping(%%) [[dimensions>>doc:sdmx:Glossary 2\.1.Dimension.WebHome]]{{footnote}}The mapping dimensions are defined as FromVtlSpaceKeys of the FromVtlSuperSpace of the VtlDataflowMapping relevant to DF2(1.0).{{/footnote}}. 452 452 453 453 The corresponding [[VTL>>doc:sdmx:Glossary 2\.1.Validation and transformation language.WebHome]] Transformations, assuming that the result needs to be persistent, would be of this kind:{{footnote}}the symbol of the VTL persistent assignment is used (<-){{/footnote}} 454 454 ... ... @@ -462,7 +462,7 @@ 462 462 > ‘DF2(1.0.0)/POPGROWTH.CANADA’ <- expression22; 463 463 > … … … 464 464 465 -As said, it is assumed that these [[VTL>>doc:sdmx:Glossary 2\.1.Validation and transformation language.WebHome]] derived [[Data Sets>>doc:sdmx:Glossary 2\.1.Data set.WebHome]] have the TIME_PERIOD as the only identifier. In the mapping from [[VTL>>doc:sdmx:Glossary 2\.1.Validation and transformation language.WebHome]] to SMDX, the [[Dimensions>>doc:sdmx:Glossary 2\.1.Dimension.WebHome]] [[INDICATOR>>doc:sdmx:Glossary 2\.1.Statistical indicator.WebHome]] and COUNTRY are added to the [[VTL>>doc:sdmx:Glossary 2\.1.Validation and transformation language.WebHome]] data structure on order to obtain the [[SDMX>>doc:sdmx:Glossary 2\.1.Statistical data and metadata exchange.WebHome]] one, with the following values respectively: 465 +As said, it is assumed that these [[VTL>>doc:sdmx:Glossary 2\.1.Validation and transformation language.WebHome]] derived [[Data Sets>>doc:sdmx:Glossary 2\.1.Data set.WebHome]] have the TIME_PERIOD as the only identifier. In the (% style="color:#e74c3c" %)mapping(%%) from [[VTL>>doc:sdmx:Glossary 2\.1.Validation and transformation language.WebHome]] to SMDX, the [[Dimensions>>doc:sdmx:Glossary 2\.1.Dimension.WebHome]] [[INDICATOR>>doc:sdmx:Glossary 2\.1.Statistical indicator.WebHome]] and COUNTRY are added to the [[VTL>>doc:sdmx:Glossary 2\.1.Validation and transformation language.WebHome]] data structure on order to obtain the [[SDMX>>doc:sdmx:Glossary 2\.1.Statistical data and metadata exchange.WebHome]] one, with the following values respectively: 466 466 467 467 > VTL dataset INDICATOR value COUNTRY value 468 468 > ... ... @@ -473,7 +473,7 @@ 473 473 > ‘DF2(1.0.0)/POPGROWTH.CANADA’ POPGROWTH CANADA 474 474 > … … … 475 475 476 -It should be noted that the application of this many-to-one mapping 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 equivalent to an appropriate sequence of [[VTL>>doc:sdmx:Glossary 2\.1.Validation and transformation language.WebHome]] Transformations. These use the [[VTL>>doc:sdmx:Glossary 2\.1.Validation and transformation language.WebHome]] operator “calc” to add the proper [[VTL>>doc:sdmx:Glossary 2\.1.Validation and transformation language.WebHome]] identifiers (in the example, [[INDICATOR>>doc:sdmx:Glossary 2\.1.Statistical indicator.WebHome]] and COUNTRY) and to assign to them the proper values and the operator “union” in order to obtain the final [[VTL>>doc:sdmx:Glossary 2\.1.Validation and transformation language.WebHome]] [[dataset>>doc:sdmx:Glossary 2\.1.Data set.WebHome]] (in the example DF2(1.0.0)), that can be mapped oneto-one to the homonymous [[SDMX>>doc:sdmx:Glossary 2\.1.Statistical data and metadata exchange.WebHome]] [[Dataflow>>doc:sdmx:Glossary 2\.1.Dataflow.WebHome]]. Following the same example, these [[VTL>>doc:sdmx:Glossary 2\.1.Validation and transformation language.WebHome]] Transformations would be: 476 +It should be noted that the application of this many-to-one (% style="color:#e74c3c" %)mapping(%%) 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 equivalent to an appropriate sequence of [[VTL>>doc:sdmx:Glossary 2\.1.Validation and transformation language.WebHome]] Transformations. These use the [[VTL>>doc:sdmx:Glossary 2\.1.Validation and transformation language.WebHome]] operator “calc” to add the proper [[VTL>>doc:sdmx:Glossary 2\.1.Validation and transformation language.WebHome]] identifiers (in the example, [[INDICATOR>>doc:sdmx:Glossary 2\.1.Statistical indicator.WebHome]] and COUNTRY) and to assign to them the proper values and the operator “union” in order to obtain the final [[VTL>>doc:sdmx:Glossary 2\.1.Validation and transformation language.WebHome]] [[dataset>>doc:sdmx:Glossary 2\.1.Data set.WebHome]] (in the example DF2(1.0.0)), that can be (% style="color:#e74c3c" %)mapped(%%) oneto-one to the homonymous [[SDMX>>doc:sdmx:Glossary 2\.1.Statistical data and metadata exchange.WebHome]] [[Dataflow>>doc:sdmx:Glossary 2\.1.Dataflow.WebHome]]. Following the same example, these [[VTL>>doc:sdmx:Glossary 2\.1.Validation and transformation language.WebHome]] Transformations would be: 477 477 478 478 > DF2bis_GDPPERCAPITA_USA := ‘DF2(1.0.0)/GDPPERCAPITA.USA’ [calc identifier INDICATOR := ”GDPPERCAPITA”, identifier COUNTRY := ”USA”]; DF2bis_GDPPERCAPITA_CANADA := ‘DF2(1.0.0)/GDPPERCAPITA.CANADA’ [calc identifier INDICATOR:=”GDPPERCAPITA”, identifier COUNTRY:=”CANADA”];… … … DF2bis_POPGROWTH_USA := ‘DF2(1.0.0)/POPGROWTH.USA’ [calc identifier INDICATOR := ”POPGROWTH”, identifier COUNTRY := ”USA”]; DF2bis_POPGROWTH_CANADA’ := ‘DF2(1.0.0)/POPGROWTH.CANADA’ [calc identifier INDICATOR := ”POPGROWTH”, identifier COUNTRY := ”CANADA”];… … … DF2(1.0) <- UNION (DF2bis_GDPPERCAPITA_USA’, DF2bis_GDPPERCAPITA_CANADA’, 479 479 > … , ... ... @@ -480,11 +480,11 @@ 480 480 > DF2bis_POPGROWTH_USA’, DF2bis_POPGROWTH_CANADA’ 481 481 > …); 482 482 483 -In other words, starting from the [[datasets>>doc:sdmx:Glossary 2\.1.Data set.WebHome]] explicitly calculated through [[VTL>>doc:sdmx:Glossary 2\.1.Validation and transformation language.WebHome]] (in the example ‘DF2(1.0)/GDPPERCAPITA.USA’ and so on), the first step consists in calculating other (non-persistent) [[VTL>>doc:sdmx:Glossary 2\.1.Validation and transformation language.WebHome]] [[datasets>>doc:sdmx:Glossary 2\.1.Data set.WebHome]] (in the example DF2bis_GDPPERCAPITA_USA and so on) by adding the identifiers [[INDICATOR>>doc:sdmx:Glossary 2\.1.Statistical indicator.WebHome]] and COUNTRY with the desired values (//INDICATORvalue// and //COUNTRYvalue)//. Finally, all these non-persistent [[Data Sets>>doc:sdmx:Glossary 2\.1.Data set.WebHome]] are united and give the final result DF2(1.0){{footnote}}The result is persistent in this example but it can be also non persistent if needed.{{/footnote}}, which can be mapped one-to-one to the homonymous [[SDMX>>doc:sdmx:Glossary 2\.1.Statistical data and metadata exchange.WebHome]] [[Dataflow>>doc:sdmx:Glossary 2\.1.Dataflow.WebHome]] having the [[dimension>>doc:sdmx:Glossary 2\.1.Dimension.WebHome]] [[components>>doc:sdmx:Glossary 2\.1.Component.WebHome]] TIME_PERIOD, [[INDICATOR>>doc:sdmx:Glossary 2\.1.Statistical indicator.WebHome]] and COUNTRY. 483 +In other words, starting from the [[datasets>>doc:sdmx:Glossary 2\.1.Data set.WebHome]] explicitly calculated through [[VTL>>doc:sdmx:Glossary 2\.1.Validation and transformation language.WebHome]] (in the example ‘DF2(1.0)/GDPPERCAPITA.USA’ and so on), the first step consists in calculating other (non-persistent) [[VTL>>doc:sdmx:Glossary 2\.1.Validation and transformation language.WebHome]] [[datasets>>doc:sdmx:Glossary 2\.1.Data set.WebHome]] (in the example DF2bis_GDPPERCAPITA_USA and so on) by adding the identifiers [[INDICATOR>>doc:sdmx:Glossary 2\.1.Statistical indicator.WebHome]] and COUNTRY with the desired values (//INDICATORvalue// and //COUNTRYvalue)//. Finally, all these non-persistent [[Data Sets>>doc:sdmx:Glossary 2\.1.Data set.WebHome]] are united and give the final result DF2(1.0){{footnote}}The result is persistent in this example but it can be also non persistent if needed.{{/footnote}}, which can be (% style="color:#e74c3c" %)mapped(%%) one-to-one to the homonymous [[SDMX>>doc:sdmx:Glossary 2\.1.Statistical data and metadata exchange.WebHome]] [[Dataflow>>doc:sdmx:Glossary 2\.1.Dataflow.WebHome]] having the [[dimension>>doc:sdmx:Glossary 2\.1.Dimension.WebHome]] [[components>>doc:sdmx:Glossary 2\.1.Component.WebHome]] TIME_PERIOD, [[INDICATOR>>doc:sdmx:Glossary 2\.1.Statistical indicator.WebHome]] and COUNTRY. 484 484 485 -Therefore, mapping different [[VTL>>doc:sdmx:Glossary 2\.1.Validation and transformation language.WebHome]] [[datasets>>doc:sdmx:Glossary 2\.1.Data set.WebHome]] having the same data structure to different parts of a [[SDMX>>doc:sdmx:Glossary 2\.1.Statistical data and metadata exchange.WebHome]] [[Dataflow>>doc:sdmx:Glossary 2\.1.Dataflow.WebHome]], i.e. in the direction 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]], through the ordered concatenation notation is equivalent to a proper use of the operators “calc” and “union” on such [[datasets>>doc:sdmx:Glossary 2\.1.Data set.WebHome]].{{footnote}}In case the ordered concatenation notation from VTL to SDMX is used, the set of Transformations described above is implicitly performed; therefore, in order to test the overall compliance of the VTL program to the VTL consistency rules, these implicit Transformations have to be considered as part of the VTL program even if they are not explicitly coded.{{/footnote}}{{footnote}}Through SDMX Constraints, it is possible to specify the values that a Component of a Dataflow can assume.{{/footnote}} 485 +Therefore, (% style="color:#e74c3c" %)mapping(%%) different [[VTL>>doc:sdmx:Glossary 2\.1.Validation and transformation language.WebHome]] [[datasets>>doc:sdmx:Glossary 2\.1.Data set.WebHome]] having the same data structure to different parts of a [[SDMX>>doc:sdmx:Glossary 2\.1.Statistical data and metadata exchange.WebHome]] [[Dataflow>>doc:sdmx:Glossary 2\.1.Dataflow.WebHome]], i.e. in the direction 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]], through the ordered concatenation notation is equivalent to a proper use of the operators “calc” and “union” on such [[datasets>>doc:sdmx:Glossary 2\.1.Data set.WebHome]].{{footnote}}In case the ordered concatenation notation from VTL to SDMX is used, the set of Transformations described above is implicitly performed; therefore, in order to test the overall compliance of the VTL program to the VTL consistency rules, these implicit Transformations have to be considered as part of the VTL program even if they are not explicitly coded.{{/footnote}}{{footnote}}Through SDMX Constraints, it is possible to specify the values that a Component of a Dataflow can assume.{{/footnote}} 486 486 487 -It is worth noting that in the direction 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]] it is mandatory to specify the value for every [[Dimension>>doc:sdmx:Glossary 2\.1.Dimension.WebHome]] on which the mapping is based (in other word, in the name of the calculated [[VTL>>doc:sdmx:Glossary 2\.1.Validation and transformation language.WebHome]] [[dataset>>doc:sdmx:Glossary 2\.1.Data set.WebHome]] is not possible to omit the value of some of the [[Dimensions>>doc:sdmx:Glossary 2\.1.Dimension.WebHome]]). 487 +It is worth noting that in the direction 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]] it is mandatory to specify the value for every [[Dimension>>doc:sdmx:Glossary 2\.1.Dimension.WebHome]] on which the (% style="color:#e74c3c" %)mapping(%%) is based (in other word, in the name of the calculated [[VTL>>doc:sdmx:Glossary 2\.1.Validation and transformation language.WebHome]] [[dataset>>doc:sdmx:Glossary 2\.1.Data set.WebHome]] is not possible to omit the value of some of the [[Dimensions>>doc:sdmx:Glossary 2\.1.Dimension.WebHome]]). 488 488 489 489 === 12.3.7 Mapping variables and value domains between VTL and SDMX === 490 490 ... ... @@ -491,9 +491,9 @@ 491 491 With reference to the [[VTL>>doc:sdmx:Glossary 2\.1.Validation and transformation language.WebHome]] “model for [[Variables>>doc:sdmx:Glossary 2\.1.Statistical variable.WebHome]] and Value domains”, the following additional mappings have to be considered: 492 492 493 493 (% style="width:706.294px" %) 494 -|(% style="width:257px" %)VTL|(% style="width:446px" %)SDMX 494 +|(% style="width:257px" %)[[VTL>>doc:sdmx:Glossary 2\.1.Validation and transformation language.WebHome]]|(% style="width:446px" %)[[SDMX>>doc:sdmx:Glossary 2\.1.Statistical data and metadata exchange.WebHome]] 495 495 |(% style="width:257px" %)**[[Data Set>>doc:sdmx:Glossary 2\.1.Data set.WebHome]] [[Component>>doc:sdmx:Glossary 2\.1.Component.WebHome]]**|(% style="width:446px" %)Although this abstraction exists in [[SDMX>>doc:sdmx:Glossary 2\.1.Statistical data and metadata exchange.WebHome]], it does not have an explicit definition and correspond to a [[Component>>doc:sdmx:Glossary 2\.1.Component.WebHome]] (either a DimensionComponent or a [[Measure>>doc:sdmx:Glossary 2\.1.Measure.WebHome]] or a DataAttribute) belonging to one specific [[Dataflow>>doc:sdmx:Glossary 2\.1.Dataflow.WebHome]]^^43^^ 496 -|(% style="width:257px" %)**Represented [[Variable>>doc:sdmx:Glossary 2\.1.Statistical variable.WebHome]]**|(% style="width:446px" %) **[[Concept>>doc:sdmx:Glossary2\.1.Concept.WebHome]]** with a definite [[Representation>>doc:sdmx:Glossary 2\.1.Representation.WebHome]]496 +|(% style="width:257px" %)**Represented [[Variable>>doc:sdmx:Glossary 2\.1.Statistical variable.WebHome]]**|(% style="width:446px" %)(% style="color:#e74c3c" %)**Concept**(%%) with a definite [[Representation>>doc:sdmx:Glossary 2\.1.Representation.WebHome]] 497 497 |(% style="width:257px" %)**Value Domain**|(% style="width:446px" %)((( 498 498 **[[Representation>>doc:sdmx:Glossary 2\.1.Representation.WebHome]]** (see the Structure 499 499 Pattern in the Base Package) ... ... @@ -513,19 +513,19 @@ 513 513 514 514 The main difference 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]] relies on the fact that the [[VTL>>doc:sdmx:Glossary 2\.1.Validation and transformation language.WebHome]] [[artefacts>>doc:sdmx:Glossary 2\.1.Artefact.WebHome]] for defining subsets of Value Domains do not exist in [[SDMX>>doc:sdmx:Glossary 2\.1.Statistical data and metadata exchange.WebHome]], therefore the [[VTL>>doc:sdmx:Glossary 2\.1.Validation and transformation language.WebHome]] features for referring to predefined subsets are not available in [[SDMX>>doc:sdmx:Glossary 2\.1.Statistical data and metadata exchange.WebHome]]. These [[artefacts>>doc:sdmx:Glossary 2\.1.Artefact.WebHome]] are the Value Domain Subset (or Set), either enumerated or described, the Set List (list of values belonging to enumerated subsets) and the [[Data Set>>doc:sdmx:Glossary 2\.1.Data set.WebHome]] [[Component>>doc:sdmx:Glossary 2\.1.Component.WebHome]] (aimed at defining the set of values that the [[Component>>doc:sdmx:Glossary 2\.1.Component.WebHome]] of a [[Data Set>>doc:sdmx:Glossary 2\.1.Data set.WebHome]] can take, possibly a subset of the [[codes>>doc:sdmx:Glossary 2\.1.Code.WebHome]] of Value Domain). 515 515 516 -Another difference consists in the fact that all Value Domains are considered as identifiable objects in [[VTL>>doc:sdmx:Glossary 2\.1.Validation and transformation language.WebHome]] either if enumerated or not, while in [[SDMX>>doc:sdmx:Glossary 2\.1.Statistical data and metadata exchange.WebHome]] the [[Codelist>>doc:sdmx:Glossary 2\.1.Code list.WebHome]] (corresponding to a [[VTL>>doc:sdmx:Glossary 2\.1.Validation and transformation language.WebHome]] enumerated Value Domain) is identifiable, while the [[SDMX>>doc:sdmx:Glossary 2\.1.Statistical data and metadata exchange.WebHome]] non-enumerated [[Representation>>doc:sdmx:Glossary 2\.1.Representation.WebHome]] (corresponding to a [[VTL>>doc:sdmx:Glossary 2\.1.Validation and transformation language.WebHome]] non-enumerated Value Domain) is not identifiable. As a consequence, the definition of the [[VTL>>doc:sdmx:Glossary 2\.1.Validation and transformation language.WebHome]] Rulesets, which in [[VTL>>doc:sdmx:Glossary 2\.1.Validation and transformation language.WebHome]] can refer either to enumerated or non-enumerated value domains, in [[SDMX>>doc:sdmx:Glossary 2\.1.Statistical data and metadata exchange.WebHome]] can refer only to enumerated Value Domains (i.e. to [[SDMX>>doc:sdmx:Glossary 2\.1.Statistical data and metadata exchange.WebHome]] [[Codelists>>doc:sdmx:Glossary 2\.1.Code list.WebHome]]). As for the mapping between [[VTL>>doc:sdmx:Glossary 2\.1.Validation and transformation language.WebHome]] [[variables>>doc:sdmx:Glossary 2\.1.Statistical variable.WebHome]] and [[SDMX>>doc:sdmx:Glossary 2\.1.Statistical data and metadata exchange.WebHome]] [[Concepts>>doc:sdmx:Glossary2\.1.Concept.WebHome]], it should be noted that these [[artefacts>>doc:sdmx:Glossary 2\.1.Artefact.WebHome]] do not coincide perfectly. In fact, the [[VTL>>doc:sdmx:Glossary 2\.1.Validation and transformation language.WebHome]] [[variables>>doc:sdmx:Glossary 2\.1.Statistical variable.WebHome]] are represented [[variables>>doc:sdmx:Glossary 2\.1.Statistical variable.WebHome]], defined always on the same Value Domain (“[[Representation>>doc:sdmx:Glossary 2\.1.Representation.WebHome]]” in [[SDMX>>doc:sdmx:Glossary 2\.1.Statistical data and metadata exchange.WebHome]]) independently of the [[data set>>doc:sdmx:Glossary 2\.1.Data set.WebHome]] / data structure in which they appear{{footnote}}By using represented variables, VTL can assume that data structures having the same variables as identifiers can be composed one another because the correspondent values can match.{{/footnote}}, while the [[SDMX>>doc:sdmx:Glossary 2\.1.Statistical data and metadata exchange.WebHome]][[Concepts>>doc:sdmx:Glossary2\.1.Concept.WebHome]]can have different [[Representations>>doc:sdmx:Glossary 2\.1.Representation.WebHome]] in different DataStructures.{{footnote}}A Concept becomes a Component in a DataStructureDefinition, and Components can have different LocalRepresentations in different DataStructureDefinitions, also overriding the (possible) base representation of the Concept.{{/footnote}} This means that one [[SDMX>>doc:sdmx:Glossary 2\.1.Statistical data and metadata exchange.WebHome]][[Concept>>doc:sdmx:Glossary2\.1.Concept.WebHome]]can correspond to many [[VTL>>doc:sdmx:Glossary 2\.1.Validation and transformation language.WebHome]] [[Variables>>doc:sdmx:Glossary 2\.1.Statistical variable.WebHome]], one for each [[representation>>doc:sdmx:Glossary 2\.1.Representation.WebHome]] the[[Concept>>doc:sdmx:Glossary2\.1.Concept.WebHome]]has.516 +Another difference consists in the fact that all Value Domains are considered as identifiable objects in [[VTL>>doc:sdmx:Glossary 2\.1.Validation and transformation language.WebHome]] either if enumerated or not, while in [[SDMX>>doc:sdmx:Glossary 2\.1.Statistical data and metadata exchange.WebHome]] the [[Codelist>>doc:sdmx:Glossary 2\.1.Code list.WebHome]] (corresponding to a [[VTL>>doc:sdmx:Glossary 2\.1.Validation and transformation language.WebHome]] enumerated Value Domain) is identifiable, while the [[SDMX>>doc:sdmx:Glossary 2\.1.Statistical data and metadata exchange.WebHome]] non-enumerated [[Representation>>doc:sdmx:Glossary 2\.1.Representation.WebHome]] (corresponding to a [[VTL>>doc:sdmx:Glossary 2\.1.Validation and transformation language.WebHome]] non-enumerated Value Domain) is not identifiable. As a consequence, the definition of the [[VTL>>doc:sdmx:Glossary 2\.1.Validation and transformation language.WebHome]] Rulesets, which in [[VTL>>doc:sdmx:Glossary 2\.1.Validation and transformation language.WebHome]] can refer either to enumerated or non-enumerated value domains, in [[SDMX>>doc:sdmx:Glossary 2\.1.Statistical data and metadata exchange.WebHome]] can refer only to enumerated Value Domains (i.e. to [[SDMX>>doc:sdmx:Glossary 2\.1.Statistical data and metadata exchange.WebHome]] [[Codelists>>doc:sdmx:Glossary 2\.1.Code list.WebHome]]). As for the (% style="color:#e74c3c" %)mapping(%%) between [[VTL>>doc:sdmx:Glossary 2\.1.Validation and transformation language.WebHome]] [[variables>>doc:sdmx:Glossary 2\.1.Statistical variable.WebHome]] and [[SDMX>>doc:sdmx:Glossary 2\.1.Statistical data and metadata exchange.WebHome]] (% style="color:#e74c3c" %)Concepts(%%), it should be noted that these [[artefacts>>doc:sdmx:Glossary 2\.1.Artefact.WebHome]] do not coincide perfectly. In fact, the [[VTL>>doc:sdmx:Glossary 2\.1.Validation and transformation language.WebHome]] [[variables>>doc:sdmx:Glossary 2\.1.Statistical variable.WebHome]] are represented [[variables>>doc:sdmx:Glossary 2\.1.Statistical variable.WebHome]], defined always on the same Value Domain (“[[Representation>>doc:sdmx:Glossary 2\.1.Representation.WebHome]]” in [[SDMX>>doc:sdmx:Glossary 2\.1.Statistical data and metadata exchange.WebHome]]) independently of the [[data set>>doc:sdmx:Glossary 2\.1.Data set.WebHome]] / data structure in which they appear{{footnote}}By using represented variables, VTL can assume that data structures having the same variables as identifiers can be composed one another because the correspondent values can match.{{/footnote}}, while the [[SDMX>>doc:sdmx:Glossary 2\.1.Statistical data and metadata exchange.WebHome]] (% style="color:#e74c3c" %)Concepts(%%) can have different [[Representations>>doc:sdmx:Glossary 2\.1.Representation.WebHome]] in different DataStructures.{{footnote}}A Concept becomes a Component in a DataStructureDefinition, and Components can have different LocalRepresentations in different DataStructureDefinitions, also overriding the (possible) base representation of the Concept.{{/footnote}} This means that one [[SDMX>>doc:sdmx:Glossary 2\.1.Statistical data and metadata exchange.WebHome]] (% style="color:#e74c3c" %)Concept(%%) can correspond to many [[VTL>>doc:sdmx:Glossary 2\.1.Validation and transformation language.WebHome]] [[Variables>>doc:sdmx:Glossary 2\.1.Statistical variable.WebHome]], one for each [[representation>>doc:sdmx:Glossary 2\.1.Representation.WebHome]] the (% style="color:#e74c3c" %)Concept(%%) has. 517 517 518 -Therefore, it is important to be aware that some [[VTL>>doc:sdmx:Glossary 2\.1.Validation and transformation language.WebHome]] operations (for example the binary operations at [[data set>>doc:sdmx:Glossary 2\.1.Data set.WebHome]] level) are consistent only if the [[components>>doc:sdmx:Glossary 2\.1.Component.WebHome]] having the same names in the operated [[VTL>>doc:sdmx:Glossary 2\.1.Validation and transformation language.WebHome]] [[Data Sets>>doc:sdmx:Glossary 2\.1.Data set.WebHome]] have also the same [[representation>>doc:sdmx:Glossary 2\.1.Representation.WebHome]] (i.e. the same Value Domain as for [[VTL>>doc:sdmx:Glossary 2\.1.Validation and transformation language.WebHome]]). For example, it is possible to obtain correct results from the [[VTL>>doc:sdmx:Glossary 2\.1.Validation and transformation language.WebHome]] expression 518 +Therefore, it is important to be aware that some [[VTL>>doc:sdmx:Glossary 2\.1.Validation and transformation language.WebHome]] operations (for example the binary operations at [[data set>>doc:sdmx:Glossary 2\.1.Data set.WebHome]] (% style="color:#e74c3c" %)level(%%)) are consistent only if the [[components>>doc:sdmx:Glossary 2\.1.Component.WebHome]] having the same names in the operated [[VTL>>doc:sdmx:Glossary 2\.1.Validation and transformation language.WebHome]] [[Data Sets>>doc:sdmx:Glossary 2\.1.Data set.WebHome]] have also the same [[representation>>doc:sdmx:Glossary 2\.1.Representation.WebHome]] (i.e. the same Value Domain as for [[VTL>>doc:sdmx:Glossary 2\.1.Validation and transformation language.WebHome]]). For example, it is possible to obtain correct results from the [[VTL>>doc:sdmx:Glossary 2\.1.Validation and transformation language.WebHome]] expression 519 519 520 520 > DS_c := DS_a + DS_b (where DS_a, DS_b, DS_c are VTL Data Sets) 521 521 522 522 if the matching [[components>>doc:sdmx:Glossary 2\.1.Component.WebHome]] in DS_a and DS_b (e.g. ref_date, geo_area, [[sector>>doc:sdmx:Glossary 2\.1.Sector.WebHome]] …) refer to the same general [[representation>>doc:sdmx:Glossary 2\.1.Representation.WebHome]]. In simpler words, DS_a and DS_b must use the same values/[[codes>>doc:sdmx:Glossary 2\.1.Code.WebHome]] (for ref_date, geo_area, [[sector>>doc:sdmx:Glossary 2\.1.Sector.WebHome]] … ), otherwise the relevant values would not match and the result of the operation would be wrong. 523 523 524 -As mentioned, the property above is not enforced by construction in [[SDMX>>doc:sdmx:Glossary 2\.1.Statistical data and metadata exchange.WebHome]], and different [[representations>>doc:sdmx:Glossary 2\.1.Representation.WebHome]] of the same [[Concept>>doc:sdmx:Glossary2\.1.Concept.WebHome]]can be not compatible one another (for example, it may happen that geo_area is represented by ISO-alpha-3 [[codes>>doc:sdmx:Glossary 2\.1.Code.WebHome]] in DS_a and by ISO alpha-2 [[codes>>doc:sdmx:Glossary 2\.1.Code.WebHome]] in DS_b). Therefore, it will be up to the definer of [[VTL>>doc:sdmx:Glossary 2\.1.Validation and transformation language.WebHome]]524 +As mentioned, the property above is not enforced by construction in [[SDMX>>doc:sdmx:Glossary 2\.1.Statistical data and metadata exchange.WebHome]], and different [[representations>>doc:sdmx:Glossary 2\.1.Representation.WebHome]] of the same (% style="color:#e74c3c" %)Concept(%%) can be not compatible one another (for example, it may happen that geo_area is represented by ISO-alpha-3 [[codes>>doc:sdmx:Glossary 2\.1.Code.WebHome]] in DS_a and by ISO alpha-2 [[codes>>doc:sdmx:Glossary 2\.1.Code.WebHome]] in DS_b). Therefore, it will be up to the definer of [[VTL>>doc:sdmx:Glossary 2\.1.Validation and transformation language.WebHome]] 525 525 526 -Transformations to ensure that the [[VTL>>doc:sdmx:Glossary 2\.1.Validation and transformation language.WebHome]] expressions are consistent with the actual [[representations>>doc:sdmx:Glossary 2\.1.Representation.WebHome]] of the correspondent [[SDMX>>doc:sdmx:Glossary 2\.1.Statistical data and metadata exchange.WebHome]] [[Concepts>>doc:sdmx:Glossary2\.1.Concept.WebHome]].526 +Transformations to ensure that the [[VTL>>doc:sdmx:Glossary 2\.1.Validation and transformation language.WebHome]] expressions are consistent with the actual [[representations>>doc:sdmx:Glossary 2\.1.Representation.WebHome]] of the correspondent [[SDMX>>doc:sdmx:Glossary 2\.1.Statistical data and metadata exchange.WebHome]] (% style="color:#e74c3c" %)Concepts(%%). 527 527 528 -It remains up to the [[SDMX>>doc:sdmx:Glossary 2\.1.Statistical data and metadata exchange.WebHome]]-[[VTL>>doc:sdmx:Glossary 2\.1.Validation and transformation language.WebHome]] definer also the assurance of the consistency between a [[VTL>>doc:sdmx:Glossary 2\.1.Validation and transformation language.WebHome]] Ruleset defined on [[Variables>>doc:sdmx:Glossary 2\.1.Statistical variable.WebHome]] and the [[SDMX>>doc:sdmx:Glossary 2\.1.Statistical data and metadata exchange.WebHome]] [[Components>>doc:sdmx:Glossary 2\.1.Component.WebHome]] on which the Ruleset is applied. In fact, a [[VTL>>doc:sdmx:Glossary 2\.1.Validation and transformation language.WebHome]] Ruleset is expressed by means of the values of the [[Variables>>doc:sdmx:Glossary 2\.1.Statistical variable.WebHome]] (i.e. [[SDMX>>doc:sdmx:Glossary 2\.1.Statistical data and metadata exchange.WebHome]] [[Concepts>>doc:sdmx:Glossary2\.1.Concept.WebHome]]), i.e. assuming definite [[representations>>doc:sdmx:Glossary 2\.1.Representation.WebHome]] for them (e.g. ISOalpha-3 for country). If the Ruleset is applied to [[SDMX>>doc:sdmx:Glossary 2\.1.Statistical data and metadata exchange.WebHome]] [[Components>>doc:sdmx:Glossary 2\.1.Component.WebHome]] that have the same name of the[[Concept>>doc:sdmx:Glossary2\.1.Concept.WebHome]]they refer to but different [[representations>>doc:sdmx:Glossary 2\.1.Representation.WebHome]] (e.g. ISO-alpha-2 for country), the Ruleset cannot work properly.528 +It remains up to the [[SDMX>>doc:sdmx:Glossary 2\.1.Statistical data and metadata exchange.WebHome]]-[[VTL>>doc:sdmx:Glossary 2\.1.Validation and transformation language.WebHome]] definer also the assurance of the consistency between a [[VTL>>doc:sdmx:Glossary 2\.1.Validation and transformation language.WebHome]] Ruleset defined on [[Variables>>doc:sdmx:Glossary 2\.1.Statistical variable.WebHome]] and the [[SDMX>>doc:sdmx:Glossary 2\.1.Statistical data and metadata exchange.WebHome]] [[Components>>doc:sdmx:Glossary 2\.1.Component.WebHome]] on which the Ruleset is applied. In fact, a [[VTL>>doc:sdmx:Glossary 2\.1.Validation and transformation language.WebHome]] Ruleset is expressed by means of the values of the [[Variables>>doc:sdmx:Glossary 2\.1.Statistical variable.WebHome]] (i.e. [[SDMX>>doc:sdmx:Glossary 2\.1.Statistical data and metadata exchange.WebHome]] (% style="color:#e74c3c" %)Concepts(%%)), i.e. assuming definite [[representations>>doc:sdmx:Glossary 2\.1.Representation.WebHome]] for them (e.g. ISOalpha-3 for country). If the Ruleset is applied to [[SDMX>>doc:sdmx:Glossary 2\.1.Statistical data and metadata exchange.WebHome]] [[Components>>doc:sdmx:Glossary 2\.1.Component.WebHome]] that have the same name of the (% style="color:#e74c3c" %)Concept(%%) they refer to but different [[representations>>doc:sdmx:Glossary 2\.1.Representation.WebHome]] (e.g. ISO-alpha-2 for country), the Ruleset cannot work properly. 529 529 530 530 == 12.4 Mapping between SDMX and VTL Data Types == 531 531 ... ... @@ -537,7 +537,7 @@ 537 537 538 538 [[image:1750070288958-132.png]] 539 539 540 -**Figure 22 – VTL Data Types** 540 +**Figure 22 – [[VTL>>doc:sdmx:Glossary 2\.1.Validation and transformation language.WebHome]] Data Types** 541 541 542 542 The [[VTL>>doc:sdmx:Glossary 2\.1.Validation and transformation language.WebHome]] scalar types are in turn subdivided in basic scalar types, which are elementary (not defined in term of other data types) and Value Domain and Set scalar types, which are defined in terms of the basic scalar types. 543 543 ... ... @@ -545,7 +545,7 @@ 545 545 546 546 [[image:1750070310572-584.png]] 547 547 548 -**Figure 23 – VTL Basic Scalar Types** 548 +**Figure 23 – [[VTL>>doc:sdmx:Glossary 2\.1.Validation and transformation language.WebHome]] Basic Scalar Types** 549 549 550 550 === 12.4.2 VTL basic scalar types and SDMX data types === 551 551 ... ... @@ -559,7 +559,7 @@ 559 559 560 560 [[SDMX>>doc:sdmx:Glossary 2\.1.Statistical data and metadata exchange.WebHome]] data types are conceived instead to support the [[data exchange>>doc:sdmx:Glossary 2\.1.Data exchange.WebHome]], therefore they do have a format, which is known by the users and correspond, in [[VTL>>doc:sdmx:Glossary 2\.1.Validation and transformation language.WebHome]] terms, to external [[representations>>doc:sdmx:Glossary 2\.1.Representation.WebHome]]. Therefore, for each [[VTL>>doc:sdmx:Glossary 2\.1.Validation and transformation language.WebHome]] basic scalar type there can be more [[SDMX>>doc:sdmx:Glossary 2\.1.Statistical data and metadata exchange.WebHome]] data types (the latter are explained in the section "General Notes for Implementers" of this document and are actually much more numerous than the former). 561 561 562 -The following paragraphs describe the mapping between the [[SDMX>>doc:sdmx:Glossary 2\.1.Statistical data and metadata exchange.WebHome]] data types and the [[VTL>>doc:sdmx:Glossary 2\.1.Validation and transformation language.WebHome]] basic scalar types. This mapping shall be presented in the two directions of possible conversion, i.e. 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. 562 +The following paragraphs describe the (% style="color:#e74c3c" %)mapping(%%) between the [[SDMX>>doc:sdmx:Glossary 2\.1.Statistical data and metadata exchange.WebHome]] data types and the [[VTL>>doc:sdmx:Glossary 2\.1.Validation and transformation language.WebHome]] basic scalar types. This (% style="color:#e74c3c" %)mapping(%%) shall be presented in the two directions of possible conversion, i.e. 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. 563 563 564 564 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]] happens when an [[SDMX>>doc:sdmx:Glossary 2\.1.Statistical data and metadata exchange.WebHome]] [[artefact>>doc:sdmx:Glossary 2\.1.Artefact.WebHome]] acts as inputs of a [[VTL>>doc:sdmx:Glossary 2\.1.Validation and transformation language.WebHome]] Transformation. As already said, in fact, at compile time the [[VTL>>doc:sdmx:Glossary 2\.1.Validation and transformation language.WebHome]] needs to know the [[VTL>>doc:sdmx:Glossary 2\.1.Validation and transformation language.WebHome]] type of the operands in order to check their compliance with the [[VTL>>doc:sdmx:Glossary 2\.1.Validation and transformation language.WebHome]] operators and at runtime it must convert the values from their external ([[SDMX>>doc:sdmx:Glossary 2\.1.Statistical data and metadata exchange.WebHome]]) [[representations>>doc:sdmx:Glossary 2\.1.Representation.WebHome]] to the corresponding internal ([[VTL>>doc:sdmx:Glossary 2\.1.Validation and transformation language.WebHome]]) ones. 565 565 ... ... @@ -567,11 +567,11 @@ 567 567 568 568 === 12.4.3 Mapping SDMX data types to VTL basic scalar types === 569 569 570 -The following table describes the default mapping for converting from the [[SDMX>>doc:sdmx:Glossary 2\.1.Statistical data and metadata exchange.WebHome]] data types to the [[VTL>>doc:sdmx:Glossary 2\.1.Validation and transformation language.WebHome]] basic scalar types. 570 +The following table describes the default (% style="color:#e74c3c" %)mapping(%%) for converting from the [[SDMX>>doc:sdmx:Glossary 2\.1.Statistical data and metadata exchange.WebHome]] data types to the [[VTL>>doc:sdmx:Glossary 2\.1.Validation and transformation language.WebHome]] basic scalar types. 571 571 572 572 (% style="width:583.294px" %) 573 -|(% style="width:360px" %)SDMX data type 574 -(BasicComponentDataType)|(% style="width:221px" %)Default VTL basic scalar type 573 +|(% style="width:360px" %)[[SDMX>>doc:sdmx:Glossary 2\.1.Statistical data and metadata exchange.WebHome]] data type 574 +(BasicComponentDataType)|(% style="width:221px" %)Default [[VTL>>doc:sdmx:Glossary 2\.1.Validation and transformation language.WebHome]] basic scalar type 575 575 |(% style="width:360px" %)((( 576 576 String 577 577 (string allowing any character) ... ... @@ -618,7 +618,7 @@ 618 618 )))|(% style="width:221px" %)number 619 619 |(% style="width:360px" %)((( 620 620 Boolean 621 -(corresponds to the XML Schema xs:boolean datatype; support the mathematical concept of 621 +(corresponds to the XML Schema xs:boolean datatype; support the mathematical (% style="color:#e74c3c" %)concept(%%) of 622 622 binary-valued logic: {true, false}) 623 623 )))|(% style="width:221px" %)boolean 624 624 |(% style="width:360px" %)((( ... ... @@ -723,7 +723,7 @@ 723 723 |(% style="width:360px" %)IdentifiableReference|(% style="width:221px" %)Metadata type – not applicable 724 724 |(% style="width:360px" %)DataSetReference|(% style="width:221px" %)Metadata type – not applicable 725 725 726 -**Figure 14 – Mappings from SDMX data types to VTL Basic Scalar Types** 726 +**Figure 14 – Mappings from [[SDMX>>doc:sdmx:Glossary 2\.1.Statistical data and metadata exchange.WebHome]] data types to [[VTL>>doc:sdmx:Glossary 2\.1.Validation and transformation language.WebHome]] Basic Scalar Types** 727 727 728 728 When [[VTL>>doc:sdmx:Glossary 2\.1.Validation and transformation language.WebHome]] takes in input [[SDMX>>doc:sdmx:Glossary 2\.1.Statistical data and metadata exchange.WebHome]] [[artefacts>>doc:sdmx:Glossary 2\.1.Artefact.WebHome]], it is assumed that a type conversion according to the table above always happens. In case a different [[VTL>>doc:sdmx:Glossary 2\.1.Validation and transformation language.WebHome]] basic scalar type is desired, it can be achieved in the [[VTL>>doc:sdmx:Glossary 2\.1.Validation and transformation language.WebHome]] program taking in input the default [[VTL>>doc:sdmx:Glossary 2\.1.Validation and transformation language.WebHome]] basic scalar type above and applying to it the [[VTL>>doc:sdmx:Glossary 2\.1.Validation and transformation language.WebHome]] type conversion features (see the implicit and explicit type conversion and the "cast" operator in the [[VTL>>doc:sdmx:Glossary 2\.1.Validation and transformation language.WebHome]] Reference Manual). 729 729 ... ... @@ -733,9 +733,9 @@ 733 733 734 734 (% style="width:748.294px" %) 735 735 |(% style="width:164px" %)((( 736 -VTL basic scalar type 736 +[[VTL>>doc:sdmx:Glossary 2\.1.Validation and transformation language.WebHome]] basic scalar type 737 737 )))|(% style="width:304px" %)((( 738 -Default SDMX data type 738 +Default [[SDMX>>doc:sdmx:Glossary 2\.1.Statistical data and metadata exchange.WebHome]] data type 739 739 (BasicComponentDataType) 740 740 )))|(% style="width:277px" %)Default output format 741 741 |(% style="width:164px" %)String|(% style="width:304px" %)String|(% style="width:277px" %)Like XML (xs:string) ... ... @@ -753,7 +753,7 @@ 753 753 |(% style="width:164px" %)Duration|(% style="width:304px" %)Duration|(% style="width:277px" %)Like XML (xs:duration) PnYnMnDTnHnMnS 754 754 |(% style="width:164px" %)Boolean|(% style="width:304px" %)Boolean|(% style="width:277px" %)Like XML (xs:boolean) with the values "true" or "false" 755 755 756 -**Figure 14 – Mappings from SDMX data types to VTL Basic Scalar Types** 756 +**Figure 14 – Mappings from [[SDMX>>doc:sdmx:Glossary 2\.1.Statistical data and metadata exchange.WebHome]] data types to [[VTL>>doc:sdmx:Glossary 2\.1.Validation and transformation language.WebHome]] Basic Scalar Types** 757 757 758 758 In case a different default conversion is desired, it can be achieved through the CustomTypeScheme and CustomType [[artefacts>>doc:sdmx:Glossary 2\.1.Artefact.WebHome]] (see also the section Transformations and Expressions of the [[SDMX information model>>doc:sdmx:Glossary 2\.1.SDMX Information Model.WebHome]]). 759 759 ... ... @@ -760,7 +760,7 @@ 760 760 The custom output formats can be specified by means of the [[VTL>>doc:sdmx:Glossary 2\.1.Validation and transformation language.WebHome]] formatting mask described in the section "Type Conversion and Formatting Mask" of the [[VTL>>doc:sdmx:Glossary 2\.1.Validation and transformation language.WebHome]] Reference Manual. Such a section describes the masks for the [[VTL>>doc:sdmx:Glossary 2\.1.Validation and transformation language.WebHome]] basic scalar types "number", "integer", "date", "time", "time_period" and "duration" and gives examples. As for the types "string" and "boolean" the [[VTL>>doc:sdmx:Glossary 2\.1.Validation and transformation language.WebHome]] conventions are extended with some other special characters as described in the following table. 761 761 762 762 (% style="width:717.294px" %) 763 -|(% colspan="2" style="width:714px" %)VTL special characters for the formatting masks 763 +|(% colspan="2" style="width:714px" %)[[VTL>>doc:sdmx:Glossary 2\.1.Validation and transformation language.WebHome]] special characters for the formatting masks 764 764 |(% colspan="2" style="width:714px" %) 765 765 |(% colspan="2" style="width:714px" %)Number 766 766 |(% style="width:122px" %)D|(% style="width:591px" %)one numeric digit (if the scientific notation is adopted, D is only for the mantissa)