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Last modified by Artur on 2025/09/10 11:19
From version 6.1
edited by Helena
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... ... @@ -78,8 +78,10 @@
78 78  * if the [[artefact>>doc:sdmx:Glossary.Artefact.WebHome]] is a [[Dimension>>doc:sdmx:Glossary.Dimension.WebHome]], TimeDimension, [[Measure>>doc:sdmx:Glossary.Measure.WebHome]] or DataAttribute (the object-id is the name of one of the [[artefacts>>doc:sdmx:Glossary.Artefact.WebHome]] above, which are data structure components)
79 79  * if the [[artefact>>doc:sdmx:Glossary.Artefact.WebHome]] is a (% style="color:#e74c3c" %)Concept(%%) (the object-id is the name of the (% style="color:#e74c3c" %)Concept(%%))
80 80  
81 -For example, by using the URN, the [[VTL>>doc:sdmx:Glossary.Validation and transformation language.WebHome]] Transformation that sums two [[SDMX>>doc:sdmx:Glossary.Statistical data and metadata exchange.WebHome]] [[Dataflows>>doc:sdmx:Glossary.Dataflow.WebHome]] DF1 and DF2 and assigns the result to a third persistent [[Dataflow>>doc:sdmx:Glossary.Dataflow.WebHome]] DFR, assuming that DF1, DF2 and DFR are the maintainedobject-id of the three [[Dataflows>>doc:sdmx:Glossary.Dataflow.WebHome]], that their (% style="color:#e74c3c" %)version(%%) is 1.0.0 and their Agency is AG, would be written as{{footnote}}Since these references to SDMX objects include non-permitted characters as per the VTL ID notation, they need to be included between single quotes, according to the VTL rules for irregular names.{{/footnote}}:
81 +For example, by using the URN, the [[VTL>>doc:sdmx:Glossary.Validation and transformation language.WebHome]] Transformation that sums two [[SDMX>>doc:sdmx:Glossary.Statistical data and metadata exchange.WebHome]] [[Dataflows>>doc:sdmx:Glossary.Dataflow.WebHome]] DF1 and DF2 and assigns the result to a third persistent [[Dataflow>>doc:sdmx:Glossary.Dataflow.WebHome]] DFR, assuming that DF1, DF2 and DFR are the maintainedobject-id of the three [[Dataflows>>doc:sdmx:Glossary.Dataflow.WebHome]], that their (% style="color:#e74c3c" %)version(%%) is 1.0.0 and their Agency is AG, would be written as
82 82  
83 +{{footnote}}Since these references to SDMX objects include non-permitted characters as per the VTL ID notation, they need to be included between single quotes, according to the VTL rules for irregular names.{{/footnote}}:
84 +
83 83  > 'urn:sdmx:org.sdmx.infomodel.datastructure.Dataflow=AG:DFR(1.0.0)' <-
84 84  > 'urn:sdmx:org.sdmx.infomodel.datastructure.Dataflow=AG:DF1(1.0.0)' +
85 85  > 'urn:sdmx:org.sdmx.infomodel.datastructure.Dataflow=AG:DF2(1.0.0)'
... ... @@ -207,7 +207,7 @@
207 207  When transforming **from [[SDMX>>doc:sdmx:Glossary.Statistical data and metadata exchange.WebHome]] to [[VTL>>doc:sdmx:Glossary.Validation and transformation language.WebHome]]**, this method consists in leaving the [[components>>doc:sdmx:Glossary.Component.WebHome]] unchanged and maintaining their names and roles, according to the following table:
208 208  
209 209  (% style="width:468.294px" %)
210 -|(% style="width:196px" %)**SDMX**|(% style="width:269px" %)**VTL**
212 +|(% style="width:196px" %)**[[SDMX>>doc:sdmx:Glossary.Statistical data and metadata exchange.WebHome]]**|(% style="width:269px" %)**[[VTL>>doc:sdmx:Glossary.Validation and transformation language.WebHome]]**
211 211  |(% style="width:196px" %)[[Dimension>>doc:sdmx:Glossary.Dimension.WebHome]]|(% style="width:269px" %)(Simple) Identifier
212 212  |(% style="width:196px" %)TimeDimension|(% style="width:269px" %)(Time) Identifier
213 213  |(% style="width:196px" %)[[Measure>>doc:sdmx:Glossary.Measure.WebHome]]|(% style="width:269px" %)[[Measure>>doc:sdmx:Glossary.Measure.WebHome]]
... ... @@ -241,7 +241,7 @@
241 241  The summary mapping table of the "pivot" mapping from [[SDMX>>doc:sdmx:Glossary.Statistical data and metadata exchange.WebHome]] to [[VTL>>doc:sdmx:Glossary.Validation and transformation language.WebHome]] for the [[SDMX>>doc:sdmx:Glossary.Statistical data and metadata exchange.WebHome]] data structures that contain a MeasureDimension is the following:
242 242  
243 243  (% style="width:739.294px" %)
244 -|(% style="width:335px" %)**SDMX**|(% style="width:400px" %)**VTL**
246 +|(% style="width:335px" %)**[[SDMX>>doc:sdmx:Glossary.Statistical data and metadata exchange.WebHome]]**|(% style="width:400px" %)**[[VTL>>doc:sdmx:Glossary.Validation and transformation language.WebHome]]**
245 245  |(% style="width:335px" %)[[Dimension>>doc:sdmx:Glossary.Dimension.WebHome]]|(% style="width:400px" %)(Simple) Identifier
246 246  |(% style="width:335px" %)TimeDimension|(% style="width:400px" %)(Time) Identifier
247 247  |(% style="width:335px" %)MeasureDimension & one [[Measure>>doc:sdmx:Glossary.Measure.WebHome]]|(% style="width:400px" %)One [[Measure>>doc:sdmx:Glossary.Measure.WebHome]] for each [[Code>>doc:sdmx:Glossary.Code.WebHome]] of the [[SDMX>>doc:sdmx:Glossary.Statistical data and metadata exchange.WebHome]] MeasureDimension
... ... @@ -281,7 +281,7 @@
281 281  Mapping table:
282 282  
283 283  (% style="width:470.294px" %)
284 -|(% style="width:262px" %)**VTL**|(% style="width:205px" %)**SDMX**
286 +|(% style="width:262px" %)**[[VTL>>doc:sdmx:Glossary.Validation and transformation language.WebHome]]**|(% style="width:205px" %)**[[SDMX>>doc:sdmx:Glossary.Statistical data and metadata exchange.WebHome]]**
285 285  |(% style="width:262px" %)(Simple) Identifier|(% style="width:205px" %)[[Dimension>>doc:sdmx:Glossary.Dimension.WebHome]]
286 286  |(% style="width:262px" %)(Time) Identifier|(% style="width:205px" %)TimeDimension
287 287  |(% style="width:262px" %)[[Measure>>doc:sdmx:Glossary.Measure.WebHome]]|(% style="width:205px" %)[[Measure>>doc:sdmx:Glossary.Measure.WebHome]]
... ... @@ -314,7 +314,7 @@
314 314  The summary mapping table of the **unpivot** mapping method is the following:
315 315  
316 316  (% style="width:638.294px" %)
317 -|(% style="width:200px" %)**VTL**|(% style="width:435px" %)**SDMX**
319 +|(% style="width:200px" %)**[[VTL>>doc:sdmx:Glossary.Validation and transformation language.WebHome]]**|(% style="width:435px" %)**[[SDMX>>doc:sdmx:Glossary.Statistical data and metadata exchange.WebHome]]**
318 318  |(% style="width:200px" %)(Simple) Identifier|(% style="width:435px" %)[[Dimension>>doc:sdmx:Glossary.Dimension.WebHome]]
319 319  |(% style="width:200px" %)(Time) Identifier|(% style="width:435px" %)TimeDimension
320 320  |(% style="width:200px" %)All [[Measure>>doc:sdmx:Glossary.Measure.WebHome]] [[Components>>doc:sdmx:Glossary.Component.WebHome]]|(% style="width:435px" %)MeasureDimension (having one [[Code>>doc:sdmx:Glossary.Code.WebHome]] for each [[VTL>>doc:sdmx:Glossary.Validation and transformation language.WebHome]] [[measure>>doc:sdmx:Glossary.Measure.WebHome]] [[component>>doc:sdmx:Glossary.Component.WebHome]]) & one [[Measure>>doc:sdmx:Glossary.Measure.WebHome]]
... ... @@ -341,7 +341,7 @@
341 341  The mapping table is the following:
342 342  
343 343  (% style="width:467.294px" %)
344 -|(% style="width:214px" %)VTL|(% style="width:250px" %)SDMX
346 +|(% style="width:214px" %)[[VTL>>doc:sdmx:Glossary.Validation and transformation language.WebHome]]|(% style="width:250px" %)[[SDMX>>doc:sdmx:Glossary.Statistical data and metadata exchange.WebHome]]
345 345  |(% style="width:214px" %)(Simple) Identifier|(% style="width:250px" %)[[Dimension>>doc:sdmx:Glossary.Dimension.WebHome]]
346 346  |(% style="width:214px" %)(Time) Identifier|(% style="width:250px" %)TimeDimension
347 347  |(% style="width:214px" %)Some [[Measures>>doc:sdmx:Glossary.Measure.WebHome]]|(% style="width:250px" %)[[Measure>>doc:sdmx:Glossary.Measure.WebHome]]
... ... @@ -444,8 +444,10 @@
444 444  
445 445  Under these hypothesis, such derived [[VTL>>doc:sdmx:Glossary.Validation and transformation language.WebHome]] [[Data Sets>>doc:sdmx:Glossary.Data set.WebHome]] can be (% style="color:#e74c3c" %)mapped(%%) to DF2(1.0.0) by declaring the DimensionComponents INDICATOR and COUNTRY as (% style="color:#e74c3c" %)mapping(%%) [[dimensions>>doc:sdmx:Glossary.Dimension.WebHome]]{{footnote}}The mapping dimensions are defined as FromVtlSpaceKeys of the FromVtlSuperSpace of the VtlDataflowMapping relevant to DF2(1.0).{{/footnote}}.
446 446  
447 -The corresponding [[VTL>>doc:sdmx:Glossary.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}}
449 +The corresponding [[VTL>>doc:sdmx:Glossary.Validation and transformation language.WebHome]] Transformations, assuming that the result needs to be persistent, would be of this kind
448 448  
451 +:{{footnote}}the symbol of the VTL persistent assignment is used (<-){{/footnote}}
452 +
449 449  > ‘DF2(1.0.0)/INDICATORvalue.COUNTRYvalue’ <- expression
450 450  
451 451  Some examples follow, for some specific values of INDICATOR and COUNTRY:
... ... @@ -485,7 +485,7 @@
485 485  With reference to the [[VTL>>doc:sdmx:Glossary.Validation and transformation language.WebHome]] “model for Variables and Value domains”, the following additional mappings have to be considered:
486 486  
487 487  (% style="width:706.294px" %)
488 -|(% style="width:257px" %)VTL|(% style="width:446px" %)SDMX
492 +|(% style="width:257px" %)[[VTL>>doc:sdmx:Glossary.Validation and transformation language.WebHome]]|(% style="width:446px" %)[[SDMX>>doc:sdmx:Glossary.Statistical data and metadata exchange.WebHome]]
489 489  |(% style="width:257px" %)**[[Data Set>>doc:sdmx:Glossary.Data set.WebHome]] [[Component>>doc:sdmx:Glossary.Component.WebHome]]**|(% style="width:446px" %)Although this abstraction exists in [[SDMX>>doc:sdmx:Glossary.Statistical data and metadata exchange.WebHome]], it does not have an explicit definition and correspond to a [[Component>>doc:sdmx:Glossary.Component.WebHome]] (either a DimensionComponent or a [[Measure>>doc:sdmx:Glossary.Measure.WebHome]] or a DataAttribute) belonging to one specific [[Dataflow>>doc:sdmx:Glossary.Dataflow.WebHome]]^^43^^
490 490  |(% style="width:257px" %)**Represented Variable**|(% style="width:446px" %)(% style="color:#e74c3c" %)**Concept**(%%) with a definite [[Representation>>doc:sdmx:Glossary.Representation.WebHome]]
491 491  |(% style="width:257px" %)**Value Domain**|(% style="width:446px" %)(((
... ... @@ -533,9 +533,9 @@
533 533  
534 534  **Figure 22 – VTL Data Types**
535 535  
536 -The [[VTL>>doc:sdmx:Glossary.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.
540 +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.
537 537  
538 -The [[VTL>>doc:sdmx:Glossary.Validation and transformation language.WebHome]] 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):
542 +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):
539 539  
540 540  [[image:1750070310572-584.png]]
541 541  
... ... @@ -543,29 +543,28 @@
543 543  
544 544  === 12.4.2 VTL basic scalar types and SDMX data types ===
545 545  
546 -The [[VTL>>doc:sdmx:Glossary.Validation and transformation language.WebHome]] assumes that a basic scalar type has a unique internal [[representation>>doc:sdmx:Glossary.Representation.WebHome]] and can have more external [[representations>>doc:sdmx:Glossary.Representation.WebHome]].
550 +The VTL assumes that a basic scalar type has a unique internal representation and can have more external representations.
547 547  
548 -The internal [[representation>>doc:sdmx:Glossary.Representation.WebHome]] is the format used within a [[VTL>>doc:sdmx:Glossary.Validation and transformation language.WebHome]] system to represent (and process) all the scalar values of a certain type. In principle, this format is hidden and not necessarily known by users. The external [[representations>>doc:sdmx:Glossary.Representation.WebHome]] are instead the external formats of the values of a certain basic scalar type, i.e. the formats known by the users. For example, the internal [[representation>>doc:sdmx:Glossary.Representation.WebHome]] of the dates can be an integer counting the days since a predefined date (e.g. from 01/01/4713 BC up to 31/12/5874897 AD like in Postgres) while two possible external [[representations>>doc:sdmx:Glossary.Representation.WebHome]] are the formats YYYY-MMGG and MM-GG-YYYY (e.g. respectively 2010-12-31 and 12-31-2010).
552 +The internal representation is the format used within a VTL system to represent (and process) all the scalar values of a certain type. In principle, this format is hidden and not necessarily known by users. The external representations are instead the external formats of the values of a certain basic scalar type, i.e. the formats known by the users. For example, the internal representation of the dates can be an integer counting the days since a predefined date (e.g. from 01/01/4713 BC up to 31/12/5874897 AD like in Postgres) while two possible external representations are the formats YYYY-MMGG and MM-GG-YYYY (e.g. respectively 2010-12-31 and 12-31-2010).
549 549  
550 -The internal [[representation>>doc:sdmx:Glossary.Representation.WebHome]] is the reference format that allows [[VTL>>doc:sdmx:Glossary.Validation and transformation language.WebHome]] to operate on more values of the same type (for example on more dates) even if such values have different external formats: these values are all converted to the unique internal [[representation>>doc:sdmx:Glossary.Representation.WebHome]] so that they can be composed together (e.g. to find the more recent date, to find the time span between these dates and so on).
554 +The internal representation is the reference format that allows VTL to operate on more values of the same type (for example on more dates) even if such values have different external formats: these values are all converted to the unique internal representation so that they can be composed together (e.g. to find the more recent date, to find the time span between these dates and so on).
551 551  
552 -The [[VTL>>doc:sdmx:Glossary.Validation and transformation language.WebHome]] assumes that a unique internal [[representation>>doc:sdmx:Glossary.Representation.WebHome]] exists for each basic scalar type but does not prescribe any particular format for it, leaving the [[VTL>>doc:sdmx:Glossary.Validation and transformation language.WebHome]] systems free to using they preferred or already existing internal format. By consequence, in [[VTL>>doc:sdmx:Glossary.Validation and transformation language.WebHome]] the basic scalar types are abstractions not associated to a specific format.
556 +The VTL assumes that a unique internal representation exists for each basic scalar type but does not prescribe any particular format for it, leaving the VTL systems free to using they preferred or already existing internal format. By consequence, in VTL the basic scalar types are abstractions not associated to a specific format.
553 553  
554 -[[SDMX>>doc:sdmx:Glossary.Statistical data and metadata exchange.WebHome]] data types are conceived instead to support the data exchange, therefore they do have a format, which is known by the users and correspond, in [[VTL>>doc:sdmx:Glossary.Validation and transformation language.WebHome]] terms, to external [[representations>>doc:sdmx:Glossary.Representation.WebHome]]. Therefore, for each [[VTL>>doc:sdmx:Glossary.Validation and transformation language.WebHome]] basic scalar type there can be more [[SDMX>>doc:sdmx:Glossary.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).
558 +SDMX data types are conceived instead to support the data exchange, therefore they do have a format, which is known by the users and correspond, in VTL terms, to external representations. Therefore, for each VTL basic scalar type there can be more SDMX 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).
555 555  
556 -The following paragraphs describe the mapping between the [[SDMX>>doc:sdmx:Glossary.Statistical data and metadata exchange.WebHome]] data types and the [[VTL>>doc:sdmx:Glossary.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.Statistical data and metadata exchange.WebHome]] to [[VTL>>doc:sdmx:Glossary.Validation and transformation language.WebHome]] and vice-versa.
560 +The following paragraphs describe the mapping between the SDMX data types and the VTL basic scalar types. This mapping shall be presented in the two directions of possible conversion, i.e. from SDMX to VTL and vice-versa.
557 557  
558 -The conversion from [[SDMX>>doc:sdmx:Glossary.Statistical data and metadata exchange.WebHome]] to [[VTL>>doc:sdmx:Glossary.Validation and transformation language.WebHome]] happens when an [[SDMX>>doc:sdmx:Glossary.Statistical data and metadata exchange.WebHome]] [[artefact>>doc:sdmx:Glossary.Artefact.WebHome]] acts as inputs of a [[VTL>>doc:sdmx:Glossary.Validation and transformation language.WebHome]] Transformation. As already said, in fact, at compile time the [[VTL>>doc:sdmx:Glossary.Validation and transformation language.WebHome]] needs to know the [[VTL>>doc:sdmx:Glossary.Validation and transformation language.WebHome]] type of the operands in order to check their compliance with the [[VTL>>doc:sdmx:Glossary.Validation and transformation language.WebHome]] operators and at runtime it must convert the values from their external ([[SDMX>>doc:sdmx:Glossary.Statistical data and metadata exchange.WebHome]]) [[representations>>doc:sdmx:Glossary.Representation.WebHome]] to the corresponding internal ([[VTL>>doc:sdmx:Glossary.Validation and transformation language.WebHome]]) ones.
562 +The conversion from SDMX to VTL happens when an SDMX artefact acts as inputs of a VTL Transformation. As already said, in fact, at compile time the VTL needs to know the VTL type of the operands in order to check their compliance with the VTL operators and at runtime it must convert the values from their external (SDMX) representations to the corresponding internal (VTL) ones.
559 559  
560 -The opposite conversion, i.e. from [[VTL>>doc:sdmx:Glossary.Validation and transformation language.WebHome]] to [[SDMX>>doc:sdmx:Glossary.Statistical data and metadata exchange.WebHome]], happens when a [[VTL>>doc:sdmx:Glossary.Validation and transformation language.WebHome]] result, i.e. a [[VTL>>doc:sdmx:Glossary.Validation and transformation language.WebHome]] [[Data Set>>doc:sdmx:Glossary.Data set.WebHome]] output of a Transformation, must become a [[SDMX>>doc:sdmx:Glossary.Statistical data and metadata exchange.WebHome]] [[artefact>>doc:sdmx:Glossary.Artefact.WebHome]] (or part of it). The values of the [[VTL>>doc:sdmx:Glossary.Validation and transformation language.WebHome]] result must be converted into the desired ([[SDMX>>doc:sdmx:Glossary.Statistical data and metadata exchange.WebHome]]) external [[representations>>doc:sdmx:Glossary.Representation.WebHome]] (data types) of the [[SDMX>>doc:sdmx:Glossary.Statistical data and metadata exchange.WebHome]] [[artefact>>doc:sdmx:Glossary.Artefact.WebHome]].
564 +The opposite conversion, i.e. from VTL to SDMX, happens when a VTL result, i.e. a VTL Data Set output of a Transformation, must become a SDMX artefact (or part of it). The values of the VTL result must be converted into the desired (SDMX) external representations (data types) of the SDMX artefact.
561 561  
562 562  === 12.4.3 Mapping SDMX data types to VTL basic scalar types ===
563 563  
564 -The following table describes the default mapping for converting from the [[SDMX>>doc:sdmx:Glossary.Statistical data and metadata exchange.WebHome]] data types to the [[VTL>>doc:sdmx:Glossary.Validation and transformation language.WebHome]] basic scalar types.
568 +The following table describes the default mapping for converting from the SDMX data types to the VTL basic scalar types.
565 565  
566 566  (% style="width:583.294px" %)
567 -|(% style="width:360px" %)SDMX data type
568 -(BasicComponentDataType)|(% style="width:221px" %)Default VTL basic scalar type
571 +|(% style="width:360px" %)SDMX data type (BasicComponentDataType)|(% style="width:221px" %)Default VTL basic scalar type
569 569  |(% style="width:360px" %)(((
570 570  String
571 571  (string allowing any character)
... ... @@ -600,8 +600,7 @@
600 600  Short
601 601  (corresponds to XML Schema xs:short datatype; between -32768 and -32767 (inclusive))
602 602  )))|(% style="width:221px" %)integer
603 -|(% style="width:360px" %)[[Decimal>>doc:sdmx:Glossary.Decimals.WebHome]]
604 -(corresponds to XML Schema xs:decimal datatype; subset of real numbers that can be represented as decimals)|(% style="width:221px" %)number
606 +|(% style="width:360px" %)Decimal (corresponds to XML Schema xs:decimal datatype; subset of real numbers that can be represented as decimals)|(% style="width:221px" %)number
605 605  |(% style="width:360px" %)(((
606 606  Float
607 607  (corresponds to XML Schema xs:float datatype; patterned after the IEEE single-precision 32-bit floating point type)
... ... @@ -612,7 +612,7 @@
612 612  )))|(% style="width:221px" %)number
613 613  |(% style="width:360px" %)(((
614 614  Boolean
615 -(corresponds to the XML Schema xs:boolean datatype; support the mathematical (% style="color:#e74c3c" %)concept(%%) of
617 +(corresponds to the XML Schema xs:boolean datatype; support the mathematical concept of
616 616  binary-valued logic: {true, false})
617 617  )))|(% style="width:221px" %)boolean
618 618  |(% style="width:360px" %)(((
... ... @@ -625,15 +625,15 @@
625 625  )))|(% style="width:221px" %)integer
626 626  |(% style="width:360px" %)(((
627 627  InclusiveValueRange
628 -([[decimal>>doc:sdmx:Glossary.Decimals.WebHome]] number within a closed interval, whose bounds are specified in the [[SDMX>>doc:sdmx:Glossary.Statistical data and metadata exchange.WebHome]] [[representation>>doc:sdmx:Glossary.Representation.WebHome]] by the [[facets>>doc:sdmx:Glossary.Facet.WebHome]] minValue and maxValue)
630 +(decimal number within a closed interval, whose bounds are specified in the SDMX representation by the facets minValue and maxValue)
629 629  )))|(% style="width:221px" %)number
630 630  |(% style="width:360px" %)(((
631 631  ExclusiveValueRange
632 -([[decimal>>doc:sdmx:Glossary.Decimals.WebHome]] number within an open interval, whose bounds are specified in the [[SDMX>>doc:sdmx:Glossary.Statistical data and metadata exchange.WebHome]] [[representation>>doc:sdmx:Glossary.Representation.WebHome]] by the [[facets>>doc:sdmx:Glossary.Facet.WebHome]] minValue and maxValue)
634 +(decimal number within an open interval, whose bounds are specified in the SDMX representation by the facets minValue and maxValue)
633 633  )))|(% style="width:221px" %)number
634 634  |(% style="width:360px" %)(((
635 635  Incremental
636 -([[decimal>>doc:sdmx:Glossary.Decimals.WebHome]] number the increased by a specific interval (defined by the interval [[facet>>doc:sdmx:Glossary.Facet.WebHome]]), which is typically enforced outside of the XML validation)
638 +(decimal number the increased by a specific interval (defined by the interval facet), which is typically enforced outside of the XML validation)
637 637  )))|(% style="width:221px" %)number
638 638  |(% style="width:360px" %)(((
639 639  ObservationalTimePeriod
... ... @@ -690,19 +690,19 @@
690 690  )))|(% style="width:221px" %)date
691 691  |(% style="width:360px" %)(((
692 692  TimeRange
693 -(YYYY-MM-DD(Thh:mm:ss)?/)
695 +(YYYY-MM-DD(Thh:mm:ss)?/<duration>)
694 694  )))|(% style="width:221px" %)time
695 695  |(% style="width:360px" %)(((
696 696  Month
697 -(MM; speicifies a month independent of a year; e.g. February is black history month in the United States)
699 +(~-~-MM; speicifies a month independent of a year; e.g. February is black history month in the United States)
698 698  )))|(% style="width:221px" %)string
699 699  |(% style="width:360px" %)(((
700 700  MonthDay
701 -(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)
703 +(~-~-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)
702 702  )))|(% style="width:221px" %)string
703 703  |(% style="width:360px" %)(((
704 704  Day
705 -(-DD; specifies a day independent of a month or year; e.g. the 15^^th^^ is payday)
707 +(~-~--DD; specifies a day independent of a month or year; e.g. the 15^^th^^ is payday)
706 706  )))|(% style="width:221px" %)string
707 707  |(% style="width:360px" %)(((
708 708  Time
... ... @@ -719,7 +719,7 @@
719 719  
720 720  **Figure 14 – Mappings from SDMX data types to VTL Basic Scalar Types**
721 721  
722 -When [[VTL>>doc:sdmx:Glossary.Validation and transformation language.WebHome]] takes in input [[SDMX>>doc:sdmx:Glossary.Statistical data and metadata exchange.WebHome]] [[artefacts>>doc:sdmx:Glossary.Artefact.WebHome]], it is assumed that a type conversion according to the table above always happens. In case a different [[VTL>>doc:sdmx:Glossary.Validation and transformation language.WebHome]] basic scalar type is desired, it can be achieved in the [[VTL>>doc:sdmx:Glossary.Validation and transformation language.WebHome]] program taking in input the default [[VTL>>doc:sdmx:Glossary.Validation and transformation language.WebHome]] basic scalar type above and applying to it the [[VTL>>doc:sdmx:Glossary.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.Validation and transformation language.WebHome]] Reference Manual).
724 +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).
723 723  
724 724  === 12.4.4 Mapping VTL basic scalar types to SDMX data types ===
725 725  
... ... @@ -749,9 +749,9 @@
749 749  
750 750  **Figure 14 – Mappings from SDMX data types to VTL Basic Scalar Types**
751 751  
752 -In case a different default conversion is desired, it can be achieved through the CustomTypeScheme and CustomType [[artefacts>>doc:sdmx:Glossary.Artefact.WebHome]] (see also the section Transformations and Expressions of the [[SDMX>>doc:sdmx:Glossary.Statistical data and metadata exchange.WebHome]] information model).
754 +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).
753 753  
754 -The custom output formats can be specified by means of the [[VTL>>doc:sdmx:Glossary.Validation and transformation language.WebHome]] formatting mask described in the section "Type Conversion and Formatting Mask" of the [[VTL>>doc:sdmx:Glossary.Validation and transformation language.WebHome]] Reference Manual. Such a section describes the masks for the [[VTL>>doc:sdmx:Glossary.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.Validation and transformation language.WebHome]] conventions are extended with some other special characters as described in the following table.
756 +The custom output formats can be specified by means of the VTL formatting mask described in the section "Type Conversion and Formatting Mask" of the VTL Reference Manual. Such a section describes the masks for the VTL basic scalar types "number", "integer", "date", "time", "time_period" and "duration" and gives examples. As for the types "string" and "boolean" the VTL conventions are extended with some other special characters as described in the following table.
755 755  
756 756  (% style="width:717.294px" %)
757 757  |(% colspan="2" style="width:714px" %)VTL special characters for the formatting masks
... ... @@ -802,27 +802,27 @@
802 802  |(% style="width:122px" %)N|(% style="width:591px" %)fixed number of digits used in the preceding textual representation of the month or the day
803 803  |(% style="width:122px" %) |(% style="width:591px" %)
804 804  
805 -The default conversion, either standard or customized, can be used to deduce automatically the [[representation>>doc:sdmx:Glossary.Representation.WebHome]] of the [[components>>doc:sdmx:Glossary.Component.WebHome]] of the result of a [[VTL>>doc:sdmx:Glossary.Validation and transformation language.WebHome]] Transformation. In alternative, the [[representation>>doc:sdmx:Glossary.Representation.WebHome]] of the resulting [[SDMX>>doc:sdmx:Glossary.Statistical data and metadata exchange.WebHome]] [[Dataflow>>doc:sdmx:Glossary.Dataflow.WebHome]] can be given explicitly by providing its DataStructureDefinition. In other words, the [[representation>>doc:sdmx:Glossary.Representation.WebHome]] specified in the [[DSD>>doc:sdmx:Glossary.Data structure definition.WebHome]], if available, overrides any default conversion{{footnote}}The representation given in the DSD should obviously be compatible with the VTL data type.{{/footnote}}.
807 +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 representation given in the DSD should obviously be compatible with the VTL data type.{{/footnote}}.
806 806  
807 807  === 12.4.3 Null Values ===
808 808  
809 -In the conversions from [[SDMX>>doc:sdmx:Glossary.Statistical data and metadata exchange.WebHome]] to [[VTL>>doc:sdmx:Glossary.Validation and transformation language.WebHome]] it is assumed by default that a missing value in [[SDMX>>doc:sdmx:Glossary.Statistical data and metadata exchange.WebHome]] becomes a NULL in [[VTL>>doc:sdmx:Glossary.Validation and transformation language.WebHome]]. After the conversion, the NULLs can be manipulated through the proper [[VTL>>doc:sdmx:Glossary.Validation and transformation language.WebHome]] operators.
811 +In the conversions from SDMX to VTL it is assumed by default that a missing value in SDMX becomes a NULL in VTL. After the conversion, the NULLs can be manipulated through the proper VTL operators.
810 810  
811 -On the other side, the [[VTL>>doc:sdmx:Glossary.Validation and transformation language.WebHome]] programs can produce in output NULL values for [[Measures>>doc:sdmx:Glossary.Measure.WebHome]] and [[Attributes>>doc:sdmx:Glossary.Attribute.WebHome]] (Null values are not allowed in the Identifiers). In the conversion from [[VTL>>doc:sdmx:Glossary.Validation and transformation language.WebHome]] to [[SDMX>>doc:sdmx:Glossary.Statistical data and metadata exchange.WebHome]], it is assumed that a NULL in [[VTL>>doc:sdmx:Glossary.Validation and transformation language.WebHome]] becomes a missing value in [[SDMX>>doc:sdmx:Glossary.Statistical data and metadata exchange.WebHome]]. In the conversion from [[VTL>>doc:sdmx:Glossary.Validation and transformation language.WebHome]] to [[SDMX>>doc:sdmx:Glossary.Statistical data and metadata exchange.WebHome]], the default assumption can be overridden, separately for each [[VTL>>doc:sdmx:Glossary.Validation and transformation language.WebHome]] basic scalar type, by specifying which the value that represents the NULL in [[SDMX>>doc:sdmx:Glossary.Statistical data and metadata exchange.WebHome]] is. This can be specified in the [[attribute>>doc:sdmx:Glossary.Attribute.WebHome]] "nullValue" of the CustomType [[artefact>>doc:sdmx:Glossary.Artefact.WebHome]] (see also the section Transformations and Expressions of the [[SDMX information model>>doc:sdmx:Glossary.SDMX Information Model.WebHome]]). A CustomType belongs to a CustomTypeScheme, which can be referenced by one or more TransformationScheme (i.e. [[VTL>>doc:sdmx:Glossary.Validation and transformation language.WebHome]] programs). The overriding assumption is applied for all the [[SDMX>>doc:sdmx:Glossary.Statistical data and metadata exchange.WebHome]] [[Dataflows>>doc:sdmx:Glossary.Dataflow.WebHome]] calculated in the TransformationScheme.
813 +On the other side, the VTL programs can produce in output NULL values for Measures and Attributes (Null values are not allowed in the Identifiers). In the conversion from VTL to SDMX, it is assumed that a NULL in VTL becomes a missing value in SDMX. In the conversion from VTL to SDMX, the default assumption can be overridden, separately for each VTL basic scalar type, by specifying which the value that represents the NULL in SDMX is. This can be specified in the attribute "nullValue" of the CustomType artefact (see also the section Transformations and Expressions of the SDMX information model). A CustomType belongs to a CustomTypeScheme, which can be referenced by one or more TransformationScheme (i.e. VTL programs). The overriding assumption is applied for all the SDMX Dataflows calculated in the TransformationScheme.
812 812  
813 813  === 12.4.5 Format of the literals used in VTL Transformations ===
814 814  
815 -The [[VTL>>doc:sdmx:Glossary.Validation and transformation language.WebHome]] programs can contain literals, i.e. specific values of certain data types written directly in the [[VTL>>doc:sdmx:Glossary.Validation and transformation language.WebHome]] definitions or expressions. The [[VTL>>doc:sdmx:Glossary.Validation and transformation language.WebHome]] does not prescribe a specific format for the literals and leave the specific [[VTL>>doc:sdmx:Glossary.Validation and transformation language.WebHome]] systems and the definers of [[VTL>>doc:sdmx:Glossary.Validation and transformation language.WebHome]] Transformations free of using their preferred formats.
817 +The VTL programs can contain literals, i.e. specific values of certain data types written directly in the VTL definitions or expressions. The VTL does not prescribe a specific format for the literals and leave the specific VTL systems and the definers of VTL Transformations free of using their preferred formats.
816 816  
817 -Given this discretion, it is essential to know which are the external [[representations>>doc:sdmx:Glossary.Representation.WebHome]] adopted for the literals in a [[VTL>>doc:sdmx:Glossary.Validation and transformation language.WebHome]] program, in order to interpret them correctly. For example, if the external format for the dates is YYYY-MM-DD the date literal 2010-0102 has the meaning of 2^^nd^^ January 2010, instead if the external format for the dates is YYYY-DD-MM the same literal has the meaning of 1^^st^^ February 2010.
819 +Given this discretion, it is essential to know which are the external representations adopted for the literals in a VTL program, in order to interpret them correctly. For example, if the external format for the dates is YYYY-MM-DD the date literal 2010-0102 has the meaning of 2^^nd^^ January 2010, instead if the external format for the dates is YYYY-DD-MM the same literal has the meaning of 1^^st^^ February 2010.
818 818  
819 -Hereinafter, i.e. in the [[SDMX>>doc:sdmx:Glossary.Statistical data and metadata exchange.WebHome]] implementation of the [[VTL>>doc:sdmx:Glossary.Validation and transformation language.WebHome]], it is assumed that the literals are expressed according to the "default output format" of the table of the previous paragraph ("Mapping [[VTL>>doc:sdmx:Glossary.Validation and transformation language.WebHome]] basic scalar types to [[SDMX>>doc:sdmx:Glossary.Statistical data and metadata exchange.WebHome]] data types") unless otherwise specified.
821 +Hereinafter, i.e. in the SDMX implementation of the VTL, it is assumed that the literals are expressed according to the "default output format" of the table of the previous paragraph ("Mapping VTL basic scalar types to SDMX data types") unless otherwise specified.
820 820  
821 -A different format can be specified in the [[attribute>>doc:sdmx:Glossary.Attribute.WebHome]] "vtlLiteralFormat" of the CustomType [[artefact>>doc:sdmx:Glossary.Artefact.WebHome]] (see also the section Transformations and Expressions of the [[SDMX information model>>doc:sdmx:Glossary.SDMX Information Model.WebHome]]).
823 +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).
822 822  
823 -Like in the case of the conversion of NULLs described in the previous paragraph, the overriding assumption is applied, for a certain [[VTL>>doc:sdmx:Glossary.Validation and transformation language.WebHome]] basic scalar type, if a value is found for the vtlLiteralFormat [[attribute>>doc:sdmx:Glossary.Attribute.WebHome]] of the CustomType of such [[VTL>>doc:sdmx:Glossary.Validation and transformation language.WebHome]] basic scalar type. The overriding assumption is applied for all the literals of a related [[VTL>>doc:sdmx:Glossary.Validation and transformation language.WebHome]] TransformationScheme.
825 +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.
824 824  
825 -In case a literal is operand of a [[VTL>>doc:sdmx:Glossary.Validation and transformation language.WebHome]] Cast operation, the format specified in the Cast overrides all the possible otherwise specified formats.
827 +In case a literal is operand of a VTL Cast operation, the format specified in the Cast overrides all the possible otherwise specified formats.
826 826  
827 827  ----
828 828