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 ... ... @@ -459,47 +459,18 @@ 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”];466 +[[image:1747388179021-814.png]] 482 482 483 -DF2bis_GDPPERCAPITA_CANADA := ‘DF2(1.0.0)/GDPPERCAPITA.CANADA’ [calc identifier INDICATOR:=”GDPPERCAPITA”, identifier COUNTRY:=”CANADA”]; … … … 484 - 485 -DF2bis_POPGROWTH_USA := ‘DF2(1.0.0)/POPGROWTH.USA’ 486 - 487 -[calc identifier INDICATOR := ”POPGROWTH”, identifier COUNTRY := ”USA”]; 488 - 489 -DF2bis_POPGROWTH_CANADA’ := ‘DF2(1.0.0)/POPGROWTH.CANADA’ [calc identifier INDICATOR := ”POPGROWTH”, identifier COUNTRY := ”CANADA”]; … … … 490 - 491 -DF2(1.0) <- UNION (DF2bis_GDPPERCAPITA_USA’, 492 - 493 -DF2bis_GDPPERCAPITA_CANADA’, 494 - 495 -… , 496 - 497 -DF2bis_POPGROWTH_USA’, 498 - 499 -DF2bis_POPGROWTH_CANADA’ 500 - 501 -…); 502 - 503 503 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 504 504 505 505 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 is persistent in this example but it can be also non persistent if needed.{{/footnote}}, which can be mapped one-to-one to the homonymous SDMX Dataflow having the dimension components TIME_PERIOD, INDICATOR and COUNTRY.
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