Changes for page 12 Validation and Transformation Language (VTL)
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... ... @@ -14,8 +14,10 @@ 14 14 15 15 The VTL language can be applied to SDMX artefacts by mapping the SDMX IM model artefacts to the model artefacts that VTL can manipulate{{footnote}}In this chapter, in order to distinguish VTL and SDMX model artefacts, the VTL ones are written in the Arial font while the SDMX ones in Courier New{{/footnote}}. Thus, the SDMX artefacts can be used in VTL as inputs and/or outputs of Transformations. It is important to be aware that the artefacts do not always have the same names in the SDMX and VTL IMs, nor do they always have the same meaning. The more evident example is given by the SDMX Dataset and the VTL "Data Set", which do not correspond one another: as a matter of fact, the VTL "Data Set" maps to the SDMX "Dataflow", while the SDMX "Dataset" has no explicit mapping to VTL (such an abstraction is not needed in the definition of VTL Transformations). A SDMX "Dataset", however, is an instance of a SDMX "Dataflow" and can be the artefact on which the VTL transformations are executed (i.e., the Transformations are defined on Dataflows and are applied to Dataflow instances that can be Datasets). 16 16 17 -The VTL programs (Transformation Schemes) are represented in SDMX through the TransformationScheme maintainable class which is composed of Transformation (nameable artefact). Each Transformation assigns the outcome of the evaluation of a VTL expression to a result.17 +The VTL programs (Transformation Schemes) are represented in SDMX through the TransformationScheme maintainable class which is composed of 18 18 19 +Transformation (nameable artefact). Each Transformation assigns the outcome of the evaluation of a VTL expression to a result. 20 + 19 19 This section does not explain the VTL language or any of the content published in the VTL guides. Rather, this is a description of how the VTL can be used in the SDMX context and applied to SDMX artefacts. 20 20 21 21 == 12.2 References to SDMX artefacts from VTL statements == ... ... @@ -26,8 +26,10 @@ 26 26 27 27 The alias of an SDMX artefact can be its URN (Universal Resource Name), an abbreviation of its URN or another user-defined name. 28 28 29 -In any case, the aliases used in the VTL Transformations have to be mapped to the SDMX artefacts through the VtlMappingScheme and VtlMapping classes (see the section of the SDMX IM relevant to the VTL). A VtlMapping allows specifying the aliases to be used in the VTL Transformations, Rulesets{{footnote}}See also the section "VTL-DL Rulesets" in the VTL Reference Manual.{{/footnote}} or User Defined Operators{{footnote}}The VTLMappings are used also for User Defined Operators (UDO). Although UDOs are envisaged to be defined on generic operands, so that the specific artefacts to be manipulated are passed as parameters at their invocation, it is also possible that an UDO invokes directly some specific SDMX artefacts. These SDMX artefacts have to be mapped to the corresponding aliases used in the definition of the UDO through the VtlMappingScheme and VtlMapping classes as well.{{/footnote}} to reference SDMX artefacts. A VtlMappingScheme is a container for zero or more VtlMapping.31 +In any case, the aliases used in the VTL Transformations have to be mapped to the 30 30 33 +SDMX artefacts through the VtlMappingScheme and VtlMapping classes (see the section of the SDMX IM relevant to the VTL). A VtlMapping allows specifying the aliases to be used in the VTL Transformations, Rulesets{{footnote}}See also the section "VTL-DL Rulesets" in the VTL Reference Manual.{{/footnote}} or User Defined Operators{{footnote}}The VTLMappings are used also for User Defined Operators (UDO). Although UDOs are envisaged to be defined on generic operands, so that the specific artefacts to be manipulated are passed as parameters at their invocation, it is also possible that an UDO invokes directly some specific SDMX artefacts. These SDMX artefacts have to be mapped to the corresponding aliases used in the definition of the UDO through the VtlMappingScheme and VtlMapping classes as well.{{/footnote}} to reference SDMX artefacts. A VtlMappingScheme is a container for zero or more VtlMapping. 34 + 31 31 The correspondence between an alias and a SDMX artefact must be one-to-one, meaning that a generic alias identifies one and just one SDMX artefact while a SDMX artefact is identified by one and just one alias. In other words, within a VtlMappingScheme an artefact can have just one alias and different artefacts cannot have the same alias. 32 32 33 33 The references through the URN and the abbreviated URN are described in the following paragraphs. ... ... @@ -198,7 +198,7 @@ 198 198 199 199 === 12.3.3 Mapping from SDMX to VTL data structures === 200 200 201 - ====12.3.3.1 Basic Mapping====205 +**12.3.3.1 Basic Mapping** 202 202 203 203 The main mapping method from SDMX to VTL 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 to VTL**, this method consists in leaving the components unchanged and maintaining their names and roles, according to the following table: 204 204 ... ... @@ -228,11 +228,18 @@ 228 228 The SDMX structures that contain a MeasureDimension are mapped as described below (this mapping is equivalent to a pivoting operation): 229 229 230 230 * A SDMX simple dimension becomes a VTL (simple) identifier and a SDMX TimeDimension becomes a VTL (time) identifier; 231 -* Each possible Code Cj of the SDMX MeasureDimension is mapped to a VTL Measure, having the same name as the SDMX Code (i.e. Cj); the VTL Measure Cj is a new VTL component even if the SDMX data structure has not such a Component; 235 +* Each possible Code Cj of the SDMX MeasureDimension is mapped to a VTL Measure, having the same name as the SDMX Code (i.e. Cj); the VTL Measure Cj is a new VTL component even if the SDMX data structure has not such a 236 + 237 +Component; 238 + 232 232 * The SDMX MeasureDimension is not mapped to VTL (it disappears in the VTL Data Structure); 233 233 * The SDMX Measure is not mapped to VTL as well (it disappears in the VTL Data Structure); 234 234 * An SDMX DataAttribute is mapped in different ways according to its AttributeRelationship: 235 -** If, according to the SDMX AttributeRelationship, the values of the DataAttribute do not depend on the values of the MeasureDimension, the SDMX DataAttribute becomes a VTL Attribute 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 level), or if it refers to a set (or a group) of dimensions which does not include the MeasureDimension; 242 +** If, according to the SDMX AttributeRelationship, the values of the DataAttribute do not depend on the values of the MeasureDimension, the SDMX DataAttribute becomes a VTL Attribute having the same name. This happens if the 243 + 244 +AttributeRelationship is not specified (i.e. the DataAttribute does not depend on any DimensionComponent and therefore is at data set level), or if it refers to a set (or a group) of dimensions which does not include the MeasureDimension; 245 + 246 +* 236 236 ** Otherwise, if, according to the SDMX AttributeRelationship, the values of the DataAttribute depend on the MeasureDimension, the SDMX DataAttribute is mapped to one VTL Attribute for each possible Code of the SDMX MeasureDimension. By default, the names of the VTL Attributes are obtained by concatenating the name of the SDMX DataAttribute and the names of the correspondent Code of the MeasureDimension separated by underscore. For example, if the SDMX DataAttribute is named DA and the possible Codes of the SDMX MeasureDimension are named C1, C2, …, Cn, then the corresponding VTL Attributes will be named DA_C1, DA_C2, …, DA_Cn (if different names are desired, they can be achieved afterwards by renaming the Attributes through VTL operators). 237 237 ** Like in the Basic mapping, the resulting VTL Attributes are considered as dependent on all the VTL identifiers (i.e. "at data point / observation level"), because VTL does not have the SDMX notion of Attribute Relationship. 238 238 ... ... @@ -431,7 +431,7 @@ 431 431 432 432 … … … 433 433 434 -In fact the VTL operator “sub” has exactly the same behaviour. Therefore, mapping different parts of a SDMX Dataflow to different VTL Data Sets in the direction from SDMX to VTL through the ordered concatenation notation is equivalent to a proper use of the operator “**sub**” on such a Dataflow. {{footnote}}Incase theordered concatenation notation is used,theVTL Transformationdescribedabove,e.g. ‘DF1(1.0)/POPULATION.USA’ := DF1(1.0) [ sub INDICATOR=“POPULATION”, COUNTRY=“USA”],isimplicitlyexecuted. Inorder totesttheoverallcomplianceoftheVTL programtotheVTL consistencyrules,ithasto beconsideredaspartoftheVTL programeven ifit isnot explicitlycoded.{{/footnote}}445 +In fact the VTL operator “sub” has exactly the same behaviour. Therefore, mapping different parts of a SDMX Dataflow to different VTL Data Sets in the direction from SDMX to VTL through the ordered concatenation notation is equivalent to a proper use of the operator “**sub**” on such a Dataflow. ^^[[(% class="wikiinternallink wikiinternallink wikiinternallink wikiinternallink wikiinternallink wikiinternallink wikiinternallink wikiinternallink wikiinternallink wikiinternallink wikiinternallink wikiinternallink wikiinternallink wikiinternallink wikiinternallink wikiinternallink wikiinternallink wikiinternallink wikiinternallink wikiinternallink wikiinternallink wikiinternallink wikiinternallink wikiinternallink wikiinternallink wikiinternallink wikiinternallink wikiinternallink wikiinternallink wikiinternallink wikiinternallink wikiinternallink wikiinternallink wikiinternallink wikiinternallink wikiinternallink" %)^^32^^>>path:#sdfootnote32sym||name="sdfootnote32anc"]](%%)^^ 435 435 436 436 In the direction from SDMX to VTL it is allowed to omit the value of one or more 437 437 ... ... @@ -459,12 +459,12 @@ 459 459 460 460 Dataflow DF2(1.0.0) having the Dimensions TIME_PERIOD, INDICATOR, 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 and COUNTRY: 461 461 462 -* each part is calculated as a VTL derived Data Set, result of a dedicated VTL Transformation; {{footnote}}Ifthe wholeDF2(1.0)iscalculatedby meansof justoneVTL Transformation,then themappingbetween theSDMX DataflowandthecorrespondingVTL dataset isone-to-one andthiskindof mapping(oneSDMX Dataflow tomanyVTL datasets)doesnotapply.{{/footnote}}463 -* the data structure of all these VTL Data Sets has the TIME_PERIOD identifier and does not have the INDICATOR and COUNTRY identifiers. {{footnote}}Thisispossible aseachVTLdatasetcorrespondstooneparticularcombinationofvaluesofINDICATORandCOUNTRY.{{/footnote}}473 +* each part is calculated as a VTL derived Data Set, result of a dedicated VTL Transformation; ^^[[(% class="wikiinternallink wikiinternallink wikiinternallink wikiinternallink wikiinternallink wikiinternallink wikiinternallink wikiinternallink wikiinternallink wikiinternallink wikiinternallink wikiinternallink wikiinternallink wikiinternallink wikiinternallink wikiinternallink wikiinternallink wikiinternallink wikiinternallink wikiinternallink wikiinternallink wikiinternallink wikiinternallink wikiinternallink wikiinternallink wikiinternallink wikiinternallink wikiinternallink wikiinternallink wikiinternallink wikiinternallink wikiinternallink wikiinternallink wikiinternallink wikiinternallink wikiinternallink" %)^^33^^>>path:#sdfootnote33sym||name="sdfootnote33anc"]](%%)^^ 474 +* the data structure of all these VTL Data Sets has the TIME_PERIOD identifier and does not have the INDICATOR and COUNTRY identifiers.^^[[(% class="wikiinternallink wikiinternallink wikiinternallink wikiinternallink wikiinternallink wikiinternallink wikiinternallink wikiinternallink wikiinternallink wikiinternallink wikiinternallink wikiinternallink wikiinternallink wikiinternallink wikiinternallink wikiinternallink wikiinternallink wikiinternallink wikiinternallink wikiinternallink wikiinternallink wikiinternallink wikiinternallink wikiinternallink wikiinternallink wikiinternallink wikiinternallink wikiinternallink wikiinternallink wikiinternallink wikiinternallink wikiinternallink wikiinternallink wikiinternallink wikiinternallink wikiinternallink" %)^^34^^>>path:#sdfootnote34sym||name="sdfootnote34anc"]](%%)^^ 464 464 465 -Under these hypothesis, such derived VTL Data Sets can be mapped to DF2(1.0.0) by declaring the DimensionComponents INDICATOR and COUNTRY as mapping dimensions {{footnote}}ThemappingdimensionsaredefinedasFromVtlSpaceKeysoftheFromVtlSuperSpaceoftheVtlDataflowMappingrelevant toDF2(1.0).{{/footnote}}.476 +Under these hypothesis, such derived VTL Data Sets can be mapped to DF2(1.0.0) by declaring the DimensionComponents INDICATOR and COUNTRY as mapping dimensions^^[[(% class="wikiinternallink wikiinternallink wikiinternallink wikiinternallink wikiinternallink wikiinternallink wikiinternallink wikiinternallink wikiinternallink wikiinternallink wikiinternallink wikiinternallink wikiinternallink wikiinternallink wikiinternallink wikiinternallink wikiinternallink wikiinternallink wikiinternallink wikiinternallink wikiinternallink wikiinternallink wikiinternallink wikiinternallink wikiinternallink wikiinternallink wikiinternallink wikiinternallink wikiinternallink wikiinternallink wikiinternallink wikiinternallink wikiinternallink wikiinternallink wikiinternallink wikiinternallink" %)^^35^^>>path:#sdfootnote35sym||name="sdfootnote35anc"]](%%)^^. 466 466 467 -The corresponding VTL Transformations, assuming that the result needs to be persistent, would be of this kind: {{footnote}}thesymboloftheVTLpersistent assignment isused(<-){{/footnote}}478 +The corresponding VTL Transformations, assuming that the result needs to be persistent, would be of this kind:^^ [[(% class="wikiinternallink wikiinternallink wikiinternallink wikiinternallink wikiinternallink wikiinternallink wikiinternallink wikiinternallink wikiinternallink wikiinternallink wikiinternallink wikiinternallink wikiinternallink wikiinternallink wikiinternallink wikiinternallink wikiinternallink wikiinternallink wikiinternallink wikiinternallink wikiinternallink wikiinternallink wikiinternallink wikiinternallink wikiinternallink wikiinternallink wikiinternallink wikiinternallink wikiinternallink wikiinternallink wikiinternallink wikiinternallink wikiinternallink wikiinternallink wikiinternallink wikiinternallink" %)^^36^^>>path:#sdfootnote36sym||name="sdfootnote36anc"]](%%)^^ 468 468 469 469 ‘DF2(1.0.0)/INDICATORvalue.COUNTRYvalue’ <- expression 470 470 ... ... @@ -520,9 +520,9 @@ 520 520 521 521 In other words, starting from the datasets explicitly calculated through VTL (in the example ‘DF2(1.0)/GDPPERCAPITA.USA’ and so on), the first step consists in calculating other (non-persistent) VTL datasets (in the example 522 522 523 -DF2bis_GDPPERCAPITA_USA and so on) by adding the identifiers INDICATOR and COUNTRY with the desired values (//INDICATORvalue// and //COUNTRYvalue)//. Finally, all these non-persistent Data Sets are united and give the final result DF2(1.0) {{footnote}}The result ispersistent in thisexamplebut itcanbe alsononpersistent ifneeded.{{/footnote}}, which can be mapped one-to-one to the homonymous SDMX Dataflow having the dimension components TIME_PERIOD, INDICATOR and COUNTRY.534 +DF2bis_GDPPERCAPITA_USA and so on) by adding the identifiers INDICATOR and COUNTRY with the desired values (//INDICATORvalue// and //COUNTRYvalue)//. Finally, all these non-persistent Data Sets are united and give the final result DF2(1.0)^^[[(% class="wikiinternallink wikiinternallink wikiinternallink wikiinternallink wikiinternallink wikiinternallink wikiinternallink wikiinternallink wikiinternallink wikiinternallink wikiinternallink wikiinternallink wikiinternallink wikiinternallink wikiinternallink wikiinternallink wikiinternallink wikiinternallink wikiinternallink wikiinternallink wikiinternallink wikiinternallink wikiinternallink wikiinternallink wikiinternallink wikiinternallink wikiinternallink wikiinternallink wikiinternallink wikiinternallink wikiinternallink wikiinternallink wikiinternallink wikiinternallink wikiinternallink wikiinternallink" %)^^37^^>>path:#sdfootnote37sym||name="sdfootnote37anc"]](%%)^^, which can be mapped one-to-one to the homonymous SDMX Dataflow having the dimension components TIME_PERIOD, INDICATOR and COUNTRY. 524 524 525 -Therefore, mapping different VTL datasets having the same data structure to different parts of a SDMX Dataflow, i.e. in the direction from VTL to SDMX, through the ordered concatenation notation is equivalent to a proper use of the operators “calc” and “union” on such datasets. {{footnote}}Incase theordered concatenation notationfromVTLto SDMXisused,thesetof Transformationsdescribedabove isimplicitlyperformed;therefore,inorder totest theoverallcomplianceoftheVTLprogramtotheVTLconsistencyrules,these implicitTransformationshave tobeconsideredaspartoftheVTLprogrameven iftheyare not explicitlycoded.{{/footnote}}536 +Therefore, mapping different VTL datasets having the same data structure to different parts of a SDMX Dataflow, i.e. in the direction from VTL to SDMX, through the ordered concatenation notation is equivalent to a proper use of the operators “calc” and “union” on such datasets. ^^[[(% class="wikiinternallink wikiinternallink wikiinternallink wikiinternallink wikiinternallink wikiinternallink wikiinternallink wikiinternallink wikiinternallink wikiinternallink wikiinternallink wikiinternallink wikiinternallink wikiinternallink wikiinternallink wikiinternallink wikiinternallink wikiinternallink wikiinternallink wikiinternallink wikiinternallink wikiinternallink wikiinternallink wikiinternallink wikiinternallink wikiinternallink wikiinternallink wikiinternallink wikiinternallink wikiinternallink wikiinternallink wikiinternallink wikiinternallink wikiinternallink wikiinternallink wikiinternallink" %)^^38^^>>path:#sdfootnote38sym||name="sdfootnote38anc"]](%%)[[(% class="wikiinternallink wikiinternallink wikiinternallink wikiinternallink wikiinternallink wikiinternallink wikiinternallink wikiinternallink wikiinternallink wikiinternallink wikiinternallink wikiinternallink wikiinternallink wikiinternallink wikiinternallink wikiinternallink wikiinternallink wikiinternallink wikiinternallink wikiinternallink wikiinternallink wikiinternallink wikiinternallink wikiinternallink wikiinternallink wikiinternallink wikiinternallink wikiinternallink wikiinternallink wikiinternallink wikiinternallink wikiinternallink wikiinternallink wikiinternallink wikiinternallink wikiinternallink" %)^^39^^>>path:#sdfootnote39sym||name="sdfootnote39anc"]](%%)^^ 526 526 527 527 It is worth noting that in the direction from VTL to SDMX it is mandatory to specify the value for every Dimension on which the mapping is based (in other word, in the name of the calculated VTL dataset is __not__ possible to omit the value of some of the Dimensions). 528 528 ... ... @@ -530,51 +530,52 @@ 530 530 531 531 With reference to the VTL “model for Variables and Value domains”, the following additional mappings have to be considered: 532 532 533 -(% style="width:1170.29px" %) 534 -|**VTL**|(% style="width:754px" %)**SDMX** 535 -|**Data Set Component**|(% style="width:754px" %)Although this abstraction exists in SDMX, it does not have an explicit definition and correspond to a Component (either a DimensionComponent or a Measure or a DataAttribute) belonging to one specific Dataflow{{footnote}}Through SDMX Constraints, it is possible to specify the values that a Component of a Dataflow can assume.{{/footnote}} 536 -|**Represented Variable**|(% style="width:754px" %)((( 544 +|VTL|SDMX 545 +|**Data Set Component**|Although this abstraction exists in SDMX, it does not have an explicit definition and correspond to a Component (either a DimensionComponent or a Measure or a DataAttribute) belonging to one specific Dataflow^^43^^ 546 +|**Represented Variable**|((( 537 537 **Concept** with a definite 538 538 539 539 Representation 540 540 ))) 541 -|**Value Domain**|( % style="width:754px" %)(((551 +|**Value Domain**|((( 542 542 **Representation** (see the Structure 543 543 544 544 Pattern in the Base Package) 545 545 ))) 546 -|**Enumerated Value Domain / Code List**| (% style="width:754px" %)**Codelist**547 -|**Code**|( % style="width:754px" %)(((556 +|**Enumerated Value Domain / Code List**|**Codelist** 557 +|**Code**|((( 548 548 **Code** (for enumerated 549 549 550 550 DimensionComponent, Measure, DataAttribute) 551 551 ))) 552 -|**Described Value Domain**|( % style="width:754px" %)(((553 -non-enumerated** Representation** 562 +|**Described Value Domain**|((( 563 +non-enumerated** Representation** 554 554 555 555 (having Facets / ExtendedFacets, see the Structure Pattern in the Base Package) 556 556 ))) 557 -|**Value**|(% style="width:754px" %)Although this abstraction exists in SDMX, it does not have an explicit definition and correspond to a **Code** of a Codelist (for enumerated Representations) or 558 -| |(% style="width:754px" %)((( 559 -to a valid **value **(for non-enumerated** **Representations) 567 +|**Value**|Although this abstraction exists in SDMX, it does not have an explicit definition and correspond to a **Code** of a Codelist (for enumerated Representations) or 568 +| |((( 569 +to a valid **value **(for non-enumerated** ** 570 + 571 +Representations) 560 560 ))) 561 -|**Value Domain Subset / Set**| (% style="width:754px" %)This abstraction does not exist in SDMX562 -|**Enumerated Value Domain Subset / Enumerated Set**| (% style="width:754px" %)This abstraction does not exist in SDMX563 -|**Described Value Domain Subset / Described Set**| (% style="width:754px" %)This abstraction does not exist in SDMX564 -|**Set list**| (% style="width:754px" %)This abstraction does not exist in SDMX573 +|**Value Domain Subset / Set**|This abstraction does not exist in SDMX 574 +|**Enumerated Value Domain Subset / Enumerated Set**|This abstraction does not exist in SDMX 575 +|**Described Value Domain Subset / Described Set**|This abstraction does not exist in SDMX 576 +|**Set list**|This abstraction does not exist in SDMX 565 565 566 566 The main difference between VTL and SDMX relies on the fact that the VTL artefacts for defining subsets of Value Domains do not exist in SDMX, therefore the VTL features for referring to predefined subsets are not available in SDMX. These artefacts 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 Component (aimed at defining the set of values that the Component of a Data Set can take, possibly a subset of the codes of Value Domain). 567 567 568 -Another difference consists in the fact that all Value Domains are considered as identifiable objects in VTL either if enumerated or not, while in SDMX the Codelist (corresponding to a VTL enumerated Value Domain) is identifiable, while the SDMX non-enumerated Representation (corresponding to a VTL non-enumerated Value Domain) is not identifiable. As a consequence, the definition of the VTL Rulesets, which in VTL can refer either to enumerated or non-enumerated value domains, in SDMX can refer only to enumerated Value Domains (i.e. to SDMX Codelists). As for the mapping between VTL variables and SDMX Concepts, it should be noted that these artefacts do not coincide perfectly. In fact, the VTL variables are represented variables, defined always on the same Value Domain (“Representation” in SDMX) independently of the data set / data structure in which they appear {{footnote}}By usingrepresented variables,VTL canassume thatdatastructures havingthesamevariablesasidentifierscanbecomposedone anotherbecause thecorrespondentvaluescanmatch.{{/footnote}}, while the SDMX Concepts can have different Representations in different DataStructures.{{footnote}}AConceptbecomesaComponentin aDataStructureDefinition,andComponents canhavedifferent LocalRepresentationsindifferentDataStructureDefinitions,alsooverridingthe(possible)base representationoftheConcept.{{/footnote}}This means that one SDMX Concept can correspond to many VTL Variables, one for each representation the Concept has.580 +Another difference consists in the fact that all Value Domains are considered as identifiable objects in VTL either if enumerated or not, while in SDMX the Codelist (corresponding to a VTL enumerated Value Domain) is identifiable, while the SDMX non-enumerated Representation (corresponding to a VTL non-enumerated Value Domain) is not identifiable. As a consequence, the definition of the VTL Rulesets, which in VTL can refer either to enumerated or non-enumerated value domains, in SDMX can refer only to enumerated Value Domains (i.e. to SDMX Codelists). As for the mapping between VTL variables and SDMX Concepts, it should be noted that these artefacts do not coincide perfectly. In fact, the VTL variables are represented variables, defined always on the same Value Domain (“Representation” in SDMX) independently of the data set / data structure in which they appear^^[[(% class="wikiinternallink wikiinternallink wikiinternallink wikiinternallink wikiinternallink wikiinternallink wikiinternallink wikiinternallink wikiinternallink wikiinternallink wikiinternallink wikiinternallink wikiinternallink wikiinternallink wikiinternallink wikiinternallink wikiinternallink wikiinternallink wikiinternallink wikiinternallink wikiinternallink wikiinternallink wikiinternallink wikiinternallink wikiinternallink wikiinternallink wikiinternallink wikiinternallink wikiinternallink wikiinternallink wikiinternallink wikiinternallink wikiinternallink wikiinternallink wikiinternallink wikiinternallink" %)^^40^^>>path:#sdfootnote40sym||name="sdfootnote40anc"]](%%)^^, while the SDMX Concepts can have different Representations in different DataStructures.^^[[(% class="wikiinternallink wikiinternallink wikiinternallink wikiinternallink wikiinternallink wikiinternallink wikiinternallink wikiinternallink wikiinternallink wikiinternallink wikiinternallink wikiinternallink wikiinternallink wikiinternallink wikiinternallink wikiinternallink wikiinternallink wikiinternallink wikiinternallink wikiinternallink wikiinternallink wikiinternallink wikiinternallink wikiinternallink wikiinternallink wikiinternallink wikiinternallink wikiinternallink wikiinternallink wikiinternallink wikiinternallink wikiinternallink wikiinternallink wikiinternallink wikiinternallink wikiinternallink" %)^^41^^>>path:#sdfootnote41sym||name="sdfootnote41anc"]](%%)^^ This means that one SDMX Concept can correspond to many VTL Variables, one for each representation the Concept has. 569 569 570 570 Therefore, it is important to be aware that some VTL operations (for example the binary operations at data set level) are consistent only if the components having the same names in the operated VTL Data Sets have also the same representation (i.e. the same Value Domain as for VTL). For example, it is possible to obtain correct results from the VTL expression 571 571 572 -DS_c := DS_a + DS_b (where DS_a, DS_b, DS_c are VTL Data Sets) 584 +DS_c := DS_a + DS_b (where DS_a, DS_b, DS_c are VTL Data Sets) if the matching components in DS_a and DS_b (e.g. ref_date, geo_area, sector …) refer to the same general representation. In simpler words, DS_a and DS_b must use the same values/codes (for ref_date, geo_area, sector … ), otherwise the relevant values would not match and the result of the operation would be wrong. 573 573 574 -if the matching components in DS_a and DS_b (e.g. ref_date, geo_area, sector …) refer to the same general representation. In simpler words, DS_a and DS_b must use the same values/codes (for ref_date, geo_area, sector … ), otherwise the relevant values would not match and the result of the operation would be wrong. 575 - 576 576 As mentioned, the property above is not enforced by construction in SDMX, and different representations of the same Concept can be not compatible one another (for example, it may happen that geo_area is represented by ISO-alpha-3 codes in DS_a and by ISO alpha-2 codes in DS_b). Therefore, it will be up to the definer of VTL 577 577 588 +[[image:SDMX 3-0-0 SECTION 6 FINAL-1.0_en_59eee18f.gif||alt="Shape5" height="1" width="192"]] 589 + 578 578 Transformations to ensure that the VTL expressions are consistent with the actual representations of the correspondent SDMX Concepts. 579 579 580 580 It remains up to the SDMX-VTL definer also the assurance of the consistency between a VTL Ruleset defined on Variables and the SDMX Components on which the Ruleset is applied. In fact, a VTL Ruleset is expressed by means of the values of the Variables (i.e. SDMX Concepts), i.e. assuming definite representations for them (e.g. ISOalpha-3 for country). If the Ruleset is applied to SDMX Components that have the same name of the Concept they refer to but different representations (e.g. ISO-alpha-2 for country), the Ruleset cannot work properly. ... ... @@ -589,8 +589,7 @@ 589 589 590 590 [[image:SDMX 3-0-0 SECTION 6 FINAL-1.0_en_e3df33ae.png||height="543" width="483"]] 591 591 592 -(% class="wikigeneratedid" id="HFigure222013VTLDataTypes" %) 593 -**Figure 22 – VTL Data Types** 604 +==== Figure 22 – VTL Data Types ==== 594 594 595 595 The VTL 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. 596 596 ... ... @@ -597,12 +597,131 @@ 597 597 The VTL basic scalar types are listed below and follow a hierarchical structure in terms of supersets/subsets (e.g. "scalar" is the superset of all the basic scalar types): 598 598 599 599 600 -**Figure 23 – VTL Basic Scalar Types** 601 601 602 602 ((( 603 - 613 +//n// 614 + 615 +//a// 616 + 617 +//e// 618 + 619 +//l// 620 + 621 +//o// 622 + 623 +//o// 624 + 625 +//B// 626 + 627 +//n// 628 + 629 +//o// 630 + 631 +//i// 632 + 633 +//t// 634 + 635 +//a// 636 + 637 +//r// 638 + 639 +//u// 640 + 641 +//D// 642 + 643 +//d// 644 + 645 +//o// 646 + 647 +//i// 648 + 649 +//r// 650 + 651 +//e// 652 + 653 +//p// 654 + 655 +//_// 656 + 657 +//e// 658 + 659 +//m// 660 + 661 +//i// 662 + 663 +//T// 664 + 665 +//e// 666 + 667 +//t// 668 + 669 +//a// 670 + 671 +//D// 672 + 673 +//e// 674 + 675 +//m// 676 + 677 +//i// 678 + 679 +//T// 680 + 681 +//r// 682 + 683 +//e// 684 + 685 +//g// 686 + 687 +//e// 688 + 689 +//t// 690 + 691 +//n// 692 + 693 +//I// 694 + 695 +//r// 696 + 697 +//e// 698 + 699 +//b// 700 + 701 +//m// 702 + 703 +//u// 704 + 705 +//N// 706 + 707 +//g// 708 + 709 +//n// 710 + 711 +//i// 712 + 713 +//r// 714 + 715 +//t// 716 + 717 +//S// 718 + 719 +//r// 720 + 721 +//a// 722 + 723 +//l// 724 + 725 +//a// 726 + 727 +//c// 728 + 729 +//S// 730 + 731 +[[image:SDMX 3-0-0 SECTION 6 FINAL-1.0_en_82d45833.gif||alt="Shape6" height="231" width="184"]] 604 604 ))) 605 605 734 +==== Figure 23 – VTL Basic Scalar Types ==== 735 + 606 606 === 12.4.2 VTL basic scalar types and SDMX data types === 607 607 608 608 The VTL assumes that a basic scalar type has a unique internal representation and can have more external representations. ... ... @@ -625,159 +625,204 @@ 625 625 626 626 The following table describes the default mapping for converting from the SDMX data types to the VTL basic scalar types. 627 627 628 -(% style="width:823.294px" %) 629 -|(% style="width:509px" %)**SDMX data type (BasicComponentDataType)**|(% style="width:312px" %)**Default VTL basic scalar type** 630 -|(% style="width:509px" %)((( 758 +|SDMX data type (BasicComponentDataType)|Default VTL basic scalar type 759 +|((( 631 631 String 761 + 632 632 (string allowing any character) 633 -)))| (%style="width:312px" %)string634 -|( % style="width:509px" %)(((763 +)))|string 764 +|((( 635 635 Alpha 766 + 636 636 (string which only allows A-z) 637 -)))| (%style="width:312px" %)string638 -|( % style="width:509px" %)(((768 +)))|string 769 +|((( 639 639 AlphaNumeric 771 + 640 640 (string which only allows A-z and 0-9) 641 -)))| (%style="width:312px" %)string642 -|( % style="width:509px" %)(((773 +)))|string 774 +|((( 643 643 Numeric 776 + 644 644 (string which only allows 0-9, but is not numeric so that is can having leading zeros) 645 -)))| (%style="width:312px" %)string646 -|( % style="width:509px" %)(((778 +)))|string 779 +|((( 647 647 BigInteger 781 + 648 648 (corresponds to XML Schema xs:integer datatype; infinite set of integer values) 649 -)))| (% style="width:312px" %)integer650 -|( % style="width:509px" %)(((783 +)))|integer 784 +|((( 651 651 Integer 652 -(corresponds to XML Schema xs:int datatype; between -2147483648 and +2147483647 (inclusive)) 653 -)))|(% style="width:312px" %)integer 654 -|(% style="width:509px" %)((( 786 + 787 +(corresponds to XML Schema xs:int datatype; between -2147483648 and +2147483647 788 + 789 +(inclusive)) 790 +)))|integer 791 +|((( 655 655 Long 656 -(corresponds to XML Schema xs:long datatype; between -9223372036854775808 and +9223372036854775807 (inclusive)) 657 -)))|(% style="width:312px" %)integer 658 -|(% style="width:509px" %)((( 793 + 794 +(corresponds to XML Schema xs:long datatype; between -9223372036854775808 and 795 + 796 ++9223372036854775807 (inclusive)) 797 +)))|integer 798 +|((( 659 659 Short 800 + 660 660 (corresponds to XML Schema xs:short datatype; between -32768 and -32767 (inclusive)) 661 -)))| (% style="width:312px" %)integer662 -| (% style="width:509px" %)Decimal (corresponds to XML Schema xs:decimal datatype; subset of real numbers that can be represented as decimals)|(% style="width:312px" %)number663 -|( % style="width:509px" %)(((802 +)))|integer 803 +|Decimal (corresponds to XML Schema xs:decimal datatype; subset of real numbers that can be represented as decimals)|number 804 +|((( 664 664 Float 806 + 665 665 (corresponds to XML Schema xs:float datatype; patterned after the IEEE single-precision 32-bit floating point type) 666 -)))| (% style="width:312px" %)number667 -|( % style="width:509px" %)(((808 +)))|number 809 +|((( 668 668 Double 811 + 669 669 (corresponds to XML Schema xs:double datatype; patterned after the IEEE double-precision 64-bit floating point type) 670 -)))| (% style="width:312px" %)number671 -|( % style="width:509px" %)(((813 +)))|number 814 +|((( 672 672 Boolean 673 -(corresponds to the XML Schema xs:boolean datatype; support the mathematical concept of binary-valued logic: {true, false}) 674 -)))|(% style="width:312px" %)boolean 675 675 676 -(% style="width:822.294px" %) 677 -|(% colspan="2" style="width:507px" %)((( 817 +(corresponds to the XML Schema xs:boolean datatype; support the mathematical concept of 818 + 819 +binary-valued logic: {true, false}) 820 +)))|boolean 821 + 822 +| |(% colspan="2" %)((( 678 678 URI 824 + 679 679 (corresponds to the XML Schema xs:anyURI; absolute or relative Uniform Resource Identifier Reference) 680 -)))|(% colspan=" 1"style="width:311px"%)string681 -|(% colspan="2" style="width:507px"%)(((826 +)))|(% colspan="2" %)string 827 +| |(% colspan="2" %)((( 682 682 Count 829 + 683 683 (an integer following a sequential pattern, increasing by 1 for each occurrence) 684 -)))|(% colspan=" 1"style="width:311px"%)integer685 -|(% colspan="2" style="width:507px"%)(((831 +)))|(% colspan="2" %)integer 832 +| |(% colspan="2" %)((( 686 686 InclusiveValueRange 834 + 687 687 (decimal number within a closed interval, whose bounds are specified in the SDMX representation by the facets minValue and maxValue) 688 -)))|(% colspan=" 1"style="width:311px"%)number689 -|(% colspan="2" style="width:507px"%)(((836 +)))|(% colspan="2" %)number 837 +| |(% colspan="2" %)((( 690 690 ExclusiveValueRange 839 + 691 691 (decimal number within an open interval, whose bounds are specified in the SDMX representation by the facets minValue and maxValue) 692 -)))|(% colspan=" 1"style="width:311px"%)number693 -|(% colspan="2" style="width:507px"%)(((841 +)))|(% colspan="2" %)number 842 +| |(% colspan="2" %)((( 694 694 Incremental 844 + 695 695 (decimal number the increased by a specific interval (defined by the interval facet), which is typically enforced outside of the XML validation) 696 -)))|(% colspan=" 1"style="width:311px"%)number697 -|(% colspan="2" style="width:507px"%)(((846 +)))|(% colspan="2" %)number 847 +| |(% colspan="2" %)((( 698 698 ObservationalTimePeriod 849 + 699 699 (superset of StandardTimePeriod and TimeRange) 700 -)))|(% colspan=" 1"style="width:311px"%)time701 -|(% colspan="2" style="width:507px"%)(((851 +)))|(% colspan="2" %)time 852 +| |(% colspan="2" %)((( 702 702 StandardTimePeriod 703 -(superset of BasicTimePeriod and ReportingTimePeriod) 704 -)))|(% colspan="1" style="width:311px" %)time 705 -|(% colspan="2" style="width:507px" %)((( 854 + 855 +(superset of BasicTimePeriod and 856 + 857 +ReportingTimePeriod) 858 +)))|(% colspan="2" %)time 859 +| |(% colspan="2" %)((( 706 706 BasicTimePeriod 861 + 707 707 (superset of GregorianTimePeriod and DateTime) 708 -)))|(% colspan=" 1"style="width:311px"%)date709 -|(% colspan="2" style="width:507px"%)(((863 +)))|(% colspan="2" %)date 864 +| |(% colspan="2" %)((( 710 710 GregorianTimePeriod 866 + 711 711 (superset of GregorianYear, GregorianYearMonth, and GregorianDay) 712 -)))|(% colspan=" 1"style="width:311px"%)date713 -|(% colspan="2" style="width:507px"%)GregorianYear (YYYY)|(% colspan="1"style="width:311px"%)date714 -|(% colspan="2" style="width:507px"%)GregorianYearMonth / GregorianMonth (YYYY-MM)|(% colspan="1"style="width:311px"%)date715 -|(% colspan="2" style="width:507px"%)GregorianDay (YYYY-MM-DD)|(% colspan="1"style="width:311px"%)date716 -|(% colspan="2" style="width:507px"%)(((868 +)))|(% colspan="2" %)date 869 +| |(% colspan="2" %)GregorianYear (YYYY)|(% colspan="2" %)date 870 +| |(% colspan="2" %)GregorianYearMonth / GregorianMonth (YYYY-MM)|(% colspan="2" %)date 871 +| |(% colspan="2" %)GregorianDay (YYYY-MM-DD)|(% colspan="2" %)date 872 +| |(% colspan="2" %)((( 717 717 ReportingTimePeriod 718 -(superset of RepostingYear, ReportingSemester, ReportingTrimester, ReportingQuarter, ReportingMonth, ReportingWeek, ReportingDay) 719 -)))|(% colspan="1" style="width:311px" %)time_period 720 -|(% colspan="2" style="width:507px" %)((( 874 + 875 +(superset of RepostingYear, ReportingSemester, 876 + 877 +ReportingTrimester, ReportingQuarter, 878 + 879 +ReportingMonth, ReportingWeek, ReportingDay) 880 +)))|(% colspan="2" %)time_period 881 +| |(% colspan="2" %)((( 721 721 ReportingYear 883 + 722 722 (YYYY-A1 – 1 year period) 723 -)))|(% colspan=" 1"style="width:311px"%)time_period724 -|(% colspan="2" style="width:507px"%)(((885 +)))|(% colspan="2" %)time_period 886 +| |(% colspan="2" %)((( 725 725 ReportingSemester 888 + 726 726 (YYYY-Ss – 6 month period) 727 -)))|(% colspan=" 1"style="width:311px"%)time_period728 -|(% colspan="2" style="width:507px"%)(((890 +)))|(% colspan="2" %)time_period 891 +| |(% colspan="2" %)((( 729 729 ReportingTrimester 893 + 730 730 (YYYY-Tt – 4 month period) 731 -)))|(% colspan=" 1"style="width:311px"%)time_period732 -|(% colspan="2" style="width:507px"%)(((895 +)))|(% colspan="2" %)time_period 896 +| |(% colspan="2" %)((( 733 733 ReportingQuarter 898 + 734 734 (YYYY-Qq – 3 month period) 735 -)))|(% colspan=" 1"style="width:311px"%)time_period736 -|(% colspan="2" style="width:507px"%)(((900 +)))|(% colspan="2" %)time_period 901 +| |(% colspan="2" %)((( 737 737 ReportingMonth 903 + 738 738 (YYYY-Mmm – 1 month period) 739 -)))|(% colspan="1" style="width:311px" %)time_period 740 -|(% colspan="2" style="width:507px" %)ReportingWeek|(% colspan="1" style="width:311px" %)time_period 741 -|(% colspan="1" style="width:507px" %)(YYYY-Www – 7 day period; following ISO 8601 definition of a week in a year)|(% colspan="2" style="width:312px" %) 742 -|(% colspan="1" style="width:507px" %)((( 905 +)))|(% colspan="2" %)time_period 906 +| |(% colspan="2" %)ReportingWeek|(% colspan="2" %)time_period 907 +| |(% colspan="2" %) |(% colspan="2" %) 908 +| |(% colspan="2" %) |(% colspan="2" %) 909 +|(% colspan="2" %)(YYYY-Www – 7 day period; following ISO 8601 definition of a week in a year)|(% colspan="2" %) | 910 +|(% colspan="2" %)((( 743 743 ReportingDay 912 + 744 744 (YYYY-Dddd – 1 day period) 745 -)))|(% colspan="2" style="width:312px"%)time_period746 -|(% colspan=" 1"style="width:507px"%)(((914 +)))|(% colspan="2" %)time_period| 915 +|(% colspan="2" %)((( 747 747 DateTime 917 + 748 748 (YYYY-MM-DDThh:mm:ss) 749 -)))|(% colspan="2" style="width:312px"%)date750 -|(% colspan=" 1"style="width:507px"%)(((919 +)))|(% colspan="2" %)date| 920 +|(% colspan="2" %)((( 751 751 TimeRange 922 + 752 752 (YYYY-MM-DD(Thh:mm:ss)?/<duration>) 753 -)))|(% colspan="2" style="width:312px"%)time754 -|(% colspan=" 1"style="width:507px"%)(((924 +)))|(% colspan="2" %)time| 925 +|(% colspan="2" %)((( 755 755 Month 927 + 756 756 (~-~-MM; speicifies a month independent of a year; e.g. February is black history month in the United States) 757 -)))|(% colspan="2" style="width:312px"%)string758 -|(% colspan=" 1"style="width:507px"%)(((929 +)))|(% colspan="2" %)string| 930 +|(% colspan="2" %)((( 759 759 MonthDay 932 + 760 760 (~-~-MM-DD; specifies a day within a month independent of a year; e.g. Christmas is December 25^^th^^; used to specify reporting year start day) 761 -)))|(% colspan="2" style="width:312px"%)string762 -|(% colspan=" 1"style="width:507px"%)(((934 +)))|(% colspan="2" %)string| 935 +|(% colspan="2" %)((( 763 763 Day 937 + 764 764 (~-~--DD; specifies a day independent of a month or year; e.g. the 15^^th^^ is payday) 765 -)))|(% colspan="2" style="width:312px"%)string766 -|(% colspan=" 1"style="width:507px"%)(((939 +)))|(% colspan="2" %)string| 940 +|(% colspan="2" %)((( 767 767 Time 942 + 768 768 (hh:mm:ss; time independent of a date; e.g. coffee break is at 10:00 AM) 769 -)))|(% colspan="2" style="width:312px"%)string770 -|(% colspan=" 1"style="width:507px"%)(((944 +)))|(% colspan="2" %)string| 945 +|(% colspan="2" %)((( 771 771 Duration 947 + 772 772 (corresponds to XML Schema xs:duration datatype) 773 -)))|(% colspan="2" style="width:312px"%)duration774 -|(% colspan=" 1"style="width:507px"%)XHTML|(% colspan="2"style="width:312px"%)Metadata type – not applicable775 -|(% colspan=" 1"style="width:507px"%)KeyValues|(% colspan="2"style="width:312px"%)Metadata type – not applicable776 -|(% colspan=" 1"style="width:507px"%)IdentifiableReference|(% colspan="2"style="width:312px"%)Metadata type – not applicable777 -|(% colspan=" 1"style="width:507px"%)DataSetReference|(% colspan="2"style="width:312px"%)Metadata type – not applicable949 +)))|(% colspan="2" %)duration| 950 +|(% colspan="2" %)XHTML|(% colspan="2" %)Metadata type – not applicable| 951 +|(% colspan="2" %)KeyValues|(% colspan="2" %)Metadata type – not applicable| 952 +|(% colspan="2" %)IdentifiableReference|(% colspan="2" %)Metadata type – not applicable| 953 +|(% colspan="2" %)DataSetReference|(% colspan="2" %)Metadata type – not applicable| 778 778 779 -(% class="wikigeneratedid" id="HFigure142013MappingsfromSDMXdatatypestoVTLBasicScalarTypes" %) 780 -**Figure 14 – Mappings from SDMX data types to VTL Basic Scalar Types** 955 +==== Figure 14 – Mappings from SDMX data types to VTL Basic Scalar Types ==== 781 781 782 782 When VTL takes in input SDMX artefacts, it is assumed that a type conversion according to the table above always happens. In case a different VTL basic scalar type is desired, it can be achieved in the VTL program taking in input the default VTL basic scalar type above and applying to it the VTL type conversion features (see the implicit and explicit type conversion and the "cast" operator in the VTL Reference Manual). 783 783 ... ... @@ -785,32 +785,39 @@ 785 785 786 786 The following table describes the default conversion from the VTL basic scalar types to the SDMX data types . 787 787 788 -(% style="width:1073.29px" %) 789 -|(% style="width:207px" %)((( 790 -**VTL basic scalar type** 791 -)))|(% style="width:462px" %)((( 792 -**Default SDMX data type (BasicComponentDataType)** 793 -)))|(% style="width:402px" %)**Default output format** 794 -|(% style="width:207px" %)String|(% style="width:462px" %)String|(% style="width:402px" %)Like XML (xs:string) 795 -|(% style="width:207px" %)Number|(% style="width:462px" %)Float|(% style="width:402px" %)Like XML (xs:float) 796 -|(% style="width:207px" %)Integer|(% style="width:462px" %)Integer|(% style="width:402px" %)Like XML (xs:int) 797 -|(% style="width:207px" %)Date|(% style="width:462px" %)DateTime|(% style="width:402px" %)YYYY-MM-DDT00:00:00Z 798 -|(% style="width:207px" %)Time|(% style="width:462px" %)StandardTimePeriod|(% style="width:402px" %)<date>/<date> (as defined above) 799 -|(% style="width:207px" %)time_period|(% style="width:462px" %)((( 963 +|((( 964 +VTL basic 965 + 966 +scalar type 967 +)))|((( 968 +Default SDMX data type 969 + 970 +(BasicComponentDataType 971 + 972 +) 973 +)))|Default output format 974 +|String|String|Like XML (xs:string) 975 +|Number|Float|Like XML (xs:float) 976 +|Integer|Integer|Like XML (xs:int) 977 +|Date|DateTime|YYYY-MM-DDT00:00:00Z 978 +|Time|StandardTimePeriod|<date>/<date> (as defined above) 979 +|time_period|((( 800 800 ReportingTimePeriod 981 + 801 801 (StandardReportingPeriod) 802 -)))|( % style="width:402px" %)(((983 +)))|((( 803 803 YYYY-Pppp 985 + 804 804 (according to SDMX ) 805 805 ))) 806 -| (% style="width:207px" %)Duration|(% style="width:462px" %)Duration|(% style="width:402px" %)(((988 +|Duration|Duration|((( 807 807 Like XML (xs:duration) 990 + 808 808 PnYnMnDTnHnMnS 809 809 ))) 810 -| (% style="width:207px" %)Boolean|(% style="width:462px" %)Boolean|(% style="width:402px" %)Like XML (xs:boolean) with the values "true" or "false"993 +|Boolean|Boolean|Like XML (xs:boolean) with the values "true" or "false" 811 811 812 -(% class="wikigeneratedid" id="HFigure142013MappingsfromSDMXdatatypestoVTLBasicScalarTypes-1" %) 813 -**Figure 14 – Mappings from SDMX data types to VTL Basic Scalar Types** 995 +==== Figure 14 – Mappings from SDMX data types to VTL Basic Scalar Types ==== 814 814 815 815 In case a different default conversion is desired, it can be achieved through the CustomTypeScheme and CustomType artefacts (see also the section Transformations and Expressions of the SDMX information model). 816 816 ... ... @@ -864,7 +864,7 @@ 864 864 |N|fixed number of digits used in the preceding textual representation of the month or the day 865 865 | | 866 866 867 -The default conversion, either standard or customized, can be used to deduce automatically the representation of the components of the result of a VTL Transformation. In alternative, the representation of the resulting SDMX Dataflow can be given explicitly by providing its DataStructureDefinition. In other words, the representation specified in the DSD, if available, overrides any default conversion {{footnote}}The representationgiven in theDSDshouldobviouslybecompatible withtheVTLdata type.{{/footnote}}.1049 +The default conversion, either standard or customized, can be used to deduce automatically the representation of the components of the result of a VTL Transformation. In alternative, the representation of the resulting SDMX Dataflow can be given explicitly by providing its DataStructureDefinition. In other words, the representation specified in the DSD, if available, overrides any default conversion^^[[(% class="wikiinternallink wikiinternallink wikiinternallink wikiinternallink wikiinternallink wikiinternallink wikiinternallink wikiinternallink wikiinternallink wikiinternallink wikiinternallink wikiinternallink wikiinternallink wikiinternallink wikiinternallink wikiinternallink wikiinternallink wikiinternallink wikiinternallink wikiinternallink wikiinternallink wikiinternallink wikiinternallink wikiinternallink wikiinternallink wikiinternallink wikiinternallink wikiinternallink wikiinternallink wikiinternallink wikiinternallink wikiinternallink wikiinternallink wikiinternallink wikiinternallink wikiinternallink" %)^^42^^>>path:#sdfootnote42sym||name="sdfootnote42anc"]](%%)^^. 868 868 869 869 === 12.4.5 Null Values === 870 870 ... ... @@ -882,8 +882,10 @@ 882 882 883 883 A different format can be specified in the attribute "vtlLiteralFormat" of the CustomType artefact (see also the section Transformations and Expressions of the SDMX information model). 884 884 885 -Like in the case of the conversion of NULLs described in the previous paragraph, the overriding assumption is applied, for a certain VTL basic scalar type, if a value is found for the vtlLiteralFormat attribute of the CustomType of such VTL basic scalar type. The overriding assumption is applied for all the literals of a related VTL TransformationScheme.1067 +Like in the case of the conversion of NULLs described in the previous paragraph, the overriding assumption is applied, for a certain VTL basic scalar type, if a value is found for the vtlLiteralFormat attribute of the CustomType of such VTL basic scalar type. The overriding assumption is applied for all the literals of a related VTL 886 886 1069 +TransformationScheme. 1070 + 887 887 In case a literal is operand of a VTL Cast operation, the format specified in the Cast overrides all the possible otherwise specified formats. 888 888 889 889 {{putFootnotes/}}