Changes for page 12 Validation and Transformation Language (VTL)
Last modified by Helena on 2025/09/10 11:19
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... ... @@ -414,13 +414,8 @@ 414 414 415 415 It should be noted that the desired VTL Data Sets (i.e. of the kind ‘DF1(1.0.0)/// INDICATORvalue//.//COUNTRYvalue//’) can be obtained also by applying the VTL operator “**sub**” (subspace) to the Dataflow DF1(1.0.0), like in the following VTL expression: 416 416 417 -‘DF1(1.0.0)/POPULATION.USA’ := 418 -DF1(1.0.0) [ sub INDICATOR=“POPULATION”, COUNTRY=“USA” ]; 417 +[[image:1747388275998-621.png]] 419 419 420 -‘DF1(1.0.0)/POPULATION.CANADA’ := 421 -DF1(1.0.0) [ sub INDICATOR=“POPULATION”, COUNTRY=“CANADA” ]; 422 -… … … 423 - 424 424 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}}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}} 425 425 426 426 In the direction from SDMX to VTL it is allowed to omit the value of one or more ... ... @@ -431,8 +431,7 @@ 431 431 432 432 This is equivalent to the application of the VTL “sub” operator only to the identifier //INDICATOR//: 433 433 434 -‘DF1(1.0.0)/POPULATION.’ := 435 -DF1(1.0.0) [ sub INDICATOR=“POPULATION” ]; 429 +[[image:1747388244829-693.png]] 436 436 437 437 Therefore the VTL Data Set ‘DF1(1.0.0)/POPULATION.’ would have the identifiers COUNTRY and TIME_PERIOD. 438 438 ... ... @@ -459,36 +459,17 @@ 459 459 460 460 Some examples follow, for some specific values of INDICATOR and COUNTRY: 461 461 462 - ‘DF2(1.0.0)/GDPPERCAPITA.USA’ <- expression11; ‘DF2(1.0.0)/GDPPERCAPITA.CANADA’ <- expression12;456 +[[image:1747388222879-916.png]] 463 463 464 -… … … 465 -‘DF2(1.0.0)/POPGROWTH.USA’ <- expression21; 466 -‘DF2(1.0.0)/POPGROWTH.CANADA’ <- expression22; 467 -… … … 458 +[[image:1747388206717-256.png]] 468 468 469 469 As said, it is assumed that these VTL derived Data Sets have the TIME_PERIOD as the only identifier. In the mapping from VTL to SMDX, the Dimensions INDICATOR and COUNTRY are added to the VTL data structure on order to obtain the SDMX one, with the following values respectively: 470 470 471 - VTL dataset INDICATOR value COUNTRY value462 +[[image:1747388148322-387.png]] 472 472 473 -‘DF2(1.0.0)/GDPPERCAPITA.USA’ GDPPERCAPITA USA 474 -‘DF2(1.0.0)/GDPPERCAPITA.CANADA’ GDPPERCAPITA CANADA … … … 475 -‘DF2(1.0.0)/POPGROWTH.USA’ POPGROWTH USA 476 -‘DF2(1.0.0)/POPGROWTH.CANADA’ POPGROWTH CANADA 477 -… … … 478 - 479 479 It should be noted that the application of this many-to-one mapping from VTL to SDMX is equivalent to an appropriate sequence of VTL Transformations. These use the VTL operator “calc” to add the proper VTL identifiers (in the example, INDICATOR and COUNTRY) and to assign to them the proper values and the operator “union” in order to obtain the final VTL dataset (in the example DF2(1.0.0)), that can be mapped oneto-one to the homonymous SDMX Dataflow. Following the same example, these VTL Transformations would be: 480 480 481 -DF2bis_GDPPERCAPITA_USA := ‘DF2(1.0.0)/GDPPERCAPITA.USA’ [calc identifier INDICATOR := ”GDPPERCAPITA”, identifier COUNTRY := ”USA”]; 482 -DF2bis_GDPPERCAPITA_CANADA := ‘DF2(1.0.0)/GDPPERCAPITA.CANADA’ [calc identifier INDICATOR:=”GDPPERCAPITA”, identifier COUNTRY:=”CANADA”]; … … … 483 -DF2bis_POPGROWTH_USA := ‘DF2(1.0.0)/POPGROWTH.USA’ 484 -[calc identifier INDICATOR := ”POPGROWTH”, identifier COUNTRY := ”USA”]; 485 -DF2bis_POPGROWTH_CANADA’ := ‘DF2(1.0.0)/POPGROWTH.CANADA’ [calc identifier INDICATOR := ”POPGROWTH”, identifier COUNTRY := ”CANADA”]; … … … 486 -DF2(1.0) <- UNION (DF2bis_GDPPERCAPITA_USA’, 487 -DF2bis_GDPPERCAPITA_CANADA’, 488 -… , 489 -DF2bis_POPGROWTH_USA’, 490 -DF2bis_POPGROWTH_CANADA’ 491 -…); 466 +[[image:1747388179021-814.png]] 492 492 493 493 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 494 494 ... ... @@ -503,37 +503,30 @@ 503 503 With reference to the VTL “model for Variables and Value domains”, the following additional mappings have to be considered: 504 504 505 505 (% style="width:1170.29px" %) 506 -|**VTL**|(% style="width:7 54px" %)**SDMX**507 -|**Data Set Component**|(% style="width:7 54px" %)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}}508 -|**Represented Variable**|(% style="width:7 54px" %)(((481 +|(% style="width:392px" %)**VTL**|(% style="width:776px" %)**SDMX** 482 +|(% style="width:392px" %)**Data Set Component**|(% style="width:776px" %)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}} 483 +|(% style="width:392px" %)**Represented Variable**|(% style="width:776px" %)((( 509 509 **Concept** with a definite 510 510 511 511 Representation 512 512 ))) 513 -|**Value Domain**|(% style="width:754px" %)((( 514 -**Representation** (see the Structure 515 - 516 -Pattern in the Base Package) 488 +|(% style="width:392px" %)**Value Domain**|(% style="width:776px" %)((( 489 +**Representation** (see the Structure Pattern in the Base Package) 517 517 ))) 518 -|**Enumerated Value Domain / Code List**|(% style="width:7 54px" %)**Codelist**519 -|**Code**|(% style="width:7 54px" %)(((491 +|(% style="width:392px" %)**Enumerated Value Domain / Code List**|(% style="width:776px" %)**Codelist** 492 +|(% style="width:392px" %)**Code**|(% style="width:776px" %)((( 520 520 **Code** (for enumerated 521 521 522 522 DimensionComponent, Measure, DataAttribute) 523 523 ))) 524 -|**Described Value Domain**|(% style="width:754px" %)((( 525 -non-enumerated** Representation** 526 - 527 -(having Facets / ExtendedFacets, see the Structure Pattern in the Base Package) 497 +|(% style="width:392px" %)**Described Value Domain**|(% style="width:776px" %)((( 498 +non-enumerated** Representation **(having Facets / ExtendedFacets, see the Structure Pattern in the Base Package) 528 528 ))) 529 -|**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 530 -| |(% style="width:754px" %)((( 531 -to a valid **value **(for non-enumerated** **Representations) 532 -))) 533 -|**Value Domain Subset / Set**|(% style="width:754px" %)This abstraction does not exist in SDMX 534 -|**Enumerated Value Domain Subset / Enumerated Set**|(% style="width:754px" %)This abstraction does not exist in SDMX 535 -|**Described Value Domain Subset / Described Set**|(% style="width:754px" %)This abstraction does not exist in SDMX 536 -|**Set list**|(% style="width:754px" %)This abstraction does not exist in SDMX 500 +|(% style="width:392px" %)**Value**|(% style="width:776px" %)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 to a valid **value **(for non-enumerated** **Representations) 501 +|(% style="width:392px" %)**Value Domain Subset / Set**|(% style="width:776px" %)This abstraction does not exist in SDMX 502 +|(% style="width:392px" %)**Enumerated Value Domain Subset / Enumerated Set**|(% style="width:776px" %)This abstraction does not exist in SDMX 503 +|(% style="width:392px" %)**Described Value Domain Subset / Described Set**|(% style="width:776px" %)This abstraction does not exist in SDMX 504 +|(% style="width:392px" %)**Set list**|(% style="width:776px" %)This abstraction does not exist in SDMX 537 537 538 538 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). 539 539
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