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
...	...	@@ -211,43 +211,55 @@
211	211
212	212	The SDMX DataAttributes, in VTL they are all considered "at data point / observation level" (i.e. dependent on all the VTL Identifiers), because VTL does not have the SDMX AttributeRelationships, which defines the construct to which the DataAttribute is related (e.g. observation, dimension or set or group of dimensions, whole data set).
213	213
214		-With the Basic mapping, one SDMX observation{{footnote}}Here an SDMX observation is meant to correspond to one combination of values of the DimensionComponents.{{/footnote}} generates one VTL data point.
	218	+With the Basic mapping, one SDMX observation^^27^^ generates one VTL data point.
215	215
216	216	==== 12.3.3.2 Pivot Mapping ====
217	217
218	218	An alternative mapping method from SDMX to VTL is the **Pivot **mapping, which makes sense and is different from the Basic method only for the SDMX data structures that contain a Dimension that plays the role of measure dimension (like in SDMX 2.1) and just one Measure. Through this method, these structures can be mapped to multimeasure VTL data structures. Besides that, a user may choose to use any Dimension acting as a list of Measures (e.g., a Dimension with indicators), either by considering the “Measure” role of a Dimension, or at will using any coded Dimension. Of course, in SDMX 3.0, this can only work when only one Measure is defined in the DSD.
219	219
220		-In SDMX 2.1 the MeasureDimension was a subclass of DimensionComponent like Dimension and TimeDimension. In the current SDMX version, this subclass does not exist anymore, however a Dimension can have the role of measure dimension (i.e. a Dimension that contributes to the identification of the measures). In SDMX 2.1 a DataStructure could have zero or one MeasureDimensions, in the current version of the standard, from zero to many Dimension may have the role of measure dimension. Hereinafter a Dimension that plays the role of measure dimension is referenced for simplicity as “MeasureDimension“, i.e. maintaining the capital letters and the courier font even if the MeasureDimension is not anymore a class in the SDMX Information Model of the current SDMX version. For the sake of simplicity, the description below considers just one Dimension having the role of MeasureDimension (i.e., the more simple and common case). Nevertheless, it maintains its validity also if in the DataStructure there are more dimension with the role of MeasureDimensions: in this case what is said about the MeasureDimension must be applied to the combination of all the MeasureDimensions considered as a joint variable{{footnote}}E.g., if in the data structure there exist 3 Dimensions C,D,E having the role of MeasureDimension, they should be considered as a joint MeasureDimension Z=(C,D,E); therefore when the description says “each possible value Cj of the MeasureDimension …” it means “each possible combination of values (Cj, Dk, Ew) of the joint MeasureDimension Z=(C,D,E)”.{{/footnote}}.
	224	+In SDMX 2.1 the MeasureDimension was a subclass of DimensionComponent like Dimension and TimeDimension. In the current SDMX version, this subclass does not exist anymore, however a Dimension can have the role of measure dimension (i.e. a Dimension that contributes to the identification of the measures). In SDMX 2.1 a DataStructure could have zero or one MeasureDimensions, in the current version of the standard, from zero to many Dimension may have the role of measure dimension. Hereinafter a Dimension that plays the role of measure dimension is referenced for simplicity as “MeasureDimension“, i.e. maintaining the capital letters and the courier font even if the MeasureDimension is not anymore a class in the SDMX Information Model of the current SDMX version. For the sake of simplicity, the description below considers just one Dimension having the role of MeasureDimension (i.e., the more simple and common case). Nevertheless, it maintains its validity also if in the DataStructure there are more dimension with the role of MeasureDimensions: in this case what is said about the MeasureDimension must be applied to the combination of all the
221	221
	226	+MeasureDimensions considered as a joint variable^^[[(% 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" %)^^24^^>>path:#sdfootnote24sym||name="sdfootnote24anc"]](%%)^^.
	227	+
222	222	Among other things, the Pivot method provides also backward compatibility with the SDMX 2.1 data structures that contained a MeasureDimension.
223	223
224	224	If applied to SDMX structures that do not contain any MeasureDimension, this method behaves like the Basic mapping (see the previous paragraph).
225	225
226		-Here an SDMX observation is meant to correspond to one combination of values of the DimensionComponents.
	232	+^^27^^ Here an SDMX observation is meant to correspond to one combination of values of the DimensionComponents.
227	227
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;
	237	+* 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
	238	+
	239	+Component;
	240	+
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;
	244	+** 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
	245	+
	246	+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;
	247	+
	248	+*
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
239	239	The summary mapping table of the "pivot" mapping from SDMX to VTL for the SDMX data structures that contain a MeasureDimension is the following:
240	240
241		-(% style="width:769.294px" %)
242		-|(% style="width:401px" %)**SDMX**|(% style="width:366px" %)**VTL**
243		-|(% style="width:401px" %)Dimension|(% style="width:366px" %)(Simple) Identifier
244		-|(% style="width:401px" %)TimeDimension|(% style="width:366px" %)(Time) Identifier
245		-|(% style="width:401px" %)MeasureDimension & one Measure|(% style="width:366px" %)(((
246		-One Measure for each Code of the SDMX MeasureDimension
	254	+|**SDMX**|**VTL**
	255	+|Dimension|(Simple) Identifier
	256	+|TimeDimension|(Time) Identifier
	257	+|MeasureDimension & one Measure|(((
	258	+One Measure for each Code of the
	259	+
	260	+SDMX MeasureDimension
247	247	)))
248		-|(% style="width:401px" %)DataAttribute not depending on the MeasureDimension|(% style="width:366px" %)Attribute
249		-|(% style="width:401px" %)DataAttribute depending on the MeasureDimension|(% style="width:366px" %)(((
250		-One Attribute for each Code of the SDMX MeasureDimension
	262	+|DataAttribute not depending on the MeasureDimension|Attribute
	263	+|DataAttribute depending on the MeasureDimension|(((
	264	+One Attribute for each Code of the
	265	+
	266	+SDMX MeasureDimension
251	251	)))
252	252
253	253	Using this mapping method, the components of the data structure can change in the conversion from SDMX to VTL and it must be taken into account that the VTL statements can reference only the components of the resulting VTL data structure.
...	...	@@ -255,11 +255,14 @@
255	255	At observation / data point level, calling Cj (j=1, … n) the j^^th^^ Code of the MeasureDimension:
256	256
257	257	* The set of SDMX observations having the same values for all the Dimensions except than the MeasureDimension become one multi-measure VTL Data Point, having one Measure for each Code Cj of the SDMX MeasureDimension;
258		-* The values of the SDMX simple Dimensions, TimeDimension and DataAttributes not depending on the MeasureDimension (these components by definition have always the same values for all the observations of the set above) become the values of the corresponding VTL (simple) Identifiers, (time) Identifier and Attributes.
	274	+* The values of the SDMX simple Dimensions, TimeDimension and DataAttributes not depending on the MeasureDimension (these components by definition have always the same values for all the observations of the set above) become the values of the corresponding VTL (simple)
	275	+
	276	+Identifiers, (time) Identifier and Attributes.
	277	+
259	259	* The value of the Measure of the SDMX observation belonging to the set above and having MeasureDimension=Cj becomes the value of the VTL Measure Cj
260	260	* For the SDMX DataAttributes depending on the MeasureDimension, the value of the DataAttribute DA of the SDMX observation belonging to the set above and having MeasureDimension=Cj becomes the value of the VTL Attribute DA_Cj
261	261
262		-==== 12.3.3.3 From SDMX DataAttributes to VTL Measures ====
	281	+**12.3.3.3 From SDMX DataAttributes to VTL Measures**
263	263
264	264	* In some cases, it may happen that the DataAttributes of the SDMX DataStructure need to be managed as Measures in VTL. Therefore, a variant of both the methods above consists in transforming all the SDMX DataAttributes in VTL Measures. When DataAttributes are converted to Measures, the two methods above are called Basic_A2M and Pivot_A2M (the suffix "A2M" stands for Attributes to Measures). Obviously, the resulting VTL data structure is, in general, multi-measure and does not contain
265	265
...	...	@@ -271,7 +271,7 @@
271	271
272	272	=== 12.3.4 Mapping from VTL to SDMX data structures ===
273	273
274		-==== 12.3.4.1 Basic Mapping ====
	293	+**12.3.4.1 Basic Mapping**
275	275
276	276	The main mapping method **from VTL to SDMX** is called **Basic **mapping as well.
277	277
...	...	@@ -281,12 +281,11 @@
281	281
282	282	Mapping table:
283	283
284		-(% style="width:667.294px" %)
285		-|(% style="width:272px" %)**VTL**|(% style="width:392px" %)**SDMX**
286		-|(% style="width:272px" %)(Simple) Identifier|(% style="width:392px" %)Dimension
287		-|(% style="width:272px" %)(Time) Identifier|(% style="width:392px" %)TimeDimension
288		-|(% style="width:272px" %)Measure|(% style="width:392px" %)Measure
289		-|(% style="width:272px" %)Attribute|(% style="width:392px" %)DataAttribute
	303	+|**VTL**|**SDMX**
	304	+|(Simple) Identifier|Dimension
	305	+|(Time) Identifier|TimeDimension
	306	+|Measure|Measure
	307	+|Attribute|DataAttribute
290	290
291	291	If the distinction between simple identifier and time identifier is not maintained in the VTL environment, the classification between Dimension and TimeDimension exists only in SDMX, as declared in the relevant DataStructureDefinition.
292	292
...	...	@@ -296,7 +296,7 @@
296	296
297	297	As said, the resulting SDMX definitions must be compliant with the SDMX consistency rules. For example, the SDMX DSD must have the AttributeRelationship for the DataAttributes, which does not exist in VTL.
298	298
299		-==== 12.3.4.2 Unpivot Mapping ====
	317	+**12.3.4.2 Unpivot Mapping**
300	300
301	301	An alternative mapping method from VTL to SDMX is the **Unpivot **mapping.
302	302
...	...	@@ -320,12 +320,11 @@
320	320
321	321	The summary mapping table of the **unpivot** mapping method is the following:
322	322
323		-(% style="width:994.294px" %)
324		-|(% style="width:306px" %)**VTL**|(% style="width:684px" %)**SDMX**
325		-|(% style="width:306px" %)(Simple) Identifier|(% style="width:684px" %)Dimension
326		-|(% style="width:306px" %)(Time) Identifier|(% style="width:684px" %)TimeDimension
327		-|(% style="width:306px" %)All Measure Components|(% style="width:684px" %)MeasureDimension (having one Code for each VTL measure component) & one Measure
328		-|(% style="width:306px" %)Attribute|(% style="width:684px" %)DataAttribute depending on all SDMX Dimensions including the TimeDimension and except the MeasureDimension
	341	+|**VTL**|**SDMX**
	342	+|(Simple) Identifier|Dimension
	343	+|(Time) Identifier|TimeDimension
	344	+|All Measure Components|MeasureDimension (having one Code for each VTL measure component) & one Measure
	345	+|Attribute|DataAttribute depending on all SDMX Dimensions including the TimeDimension and except the MeasureDimension
329	329
330	330	At observation / data point level:
331	331
...	...	@@ -339,7 +339,7 @@
339	339
340	340	In any case, the resulting SDMX definitions must be compliant with the SDMX consistency rules. For example, the possible Codes of the SDMX MeasureDimension need to be listed in a SDMX Codelist, with proper id, agency and version; moreover, the SDMX DSD must have the AttributeRelationship for the DataAttributes, which does not exist in VTL.
341	341
342		-==== 12.3.4.3 From VTL Measures to SDMX Data Attributes ====
	359	+**12.3.4.3 From VTL Measures to SDMX Data Attributes**
343	343
344	344	More than all for the multi-measure VTL structures (having more than one Measure Component), it may happen that the Measures of the VTL Data Structure need to be managed as DataAttributes in SDMX. Therefore, a third mapping method consists in transforming some VTL measures in a corresponding SDMX Measures and all the other VTL Measures in SDMX DataAttributes. This method is called M2A (“M2A” stands for “Measures to DataAttributes”).
345	345
...	...	@@ -347,13 +347,12 @@
347	347
348	348	The mapping table is the following:
349	349
350		-(% style="width:689.294px" %)
351		-|(% style="width:344px" %)**VTL**|(% style="width:341px" %)**SDMX**
352		-|(% style="width:344px" %)(Simple) Identifier|(% style="width:341px" %)Dimension
353		-|(% style="width:344px" %)(Time) Identifier|(% style="width:341px" %)TimeDimension
354		-|(% style="width:344px" %)Some Measures|(% style="width:341px" %)Measure
355		-|(% style="width:344px" %)Other Measures|(% style="width:341px" %)DataAttribute
356		-|(% style="width:344px" %)Attribute|(% style="width:341px" %)DataAttribute
	367	+|VTL|SDMX
	368	+|(Simple) Identifier|Dimension
	369	+|(Time) Identifier|TimeDimension
	370	+|Some Measures|Measure
	371	+|Other Measures|DataAttribute
	372	+|Attribute|DataAttribute
357	357
358	358	Even in this case, the resulting SDMX definitions must be compliant with the SDMX consistency rules. For example, the SDMX DSD must have the attributeRelationship for the DataAttributes, which does not exist in VTL.
359	359
...	...	@@ -371,20 +371,20 @@
371	371
372	372	Until now it has been assumed to map one SMDX Dataflow to one VTL Data Set and vice-versa. This mapping one-to-one is not mandatory according to VTL because a VTL Data Set is meant to be a set of observations (data points) on a logical plane, having the same logical data structure and the same general meaning, independently of the possible physical representation or storage (see VTL 2.0 User Manual page 24), therefore a SDMX Dataflow can be seen either as a unique set of data observations (corresponding to one VTL Data Set) or as the union of many sets of data observations (each one corresponding to a distinct VTL Data Set).
373	373
374		-As a matter of fact, in some cases it can be useful to define VTL operations involving definite parts of a SDMX Dataflow instead than the whole.{{footnote}}A typical example of this kind is the validation, and more in general the manipulation, of individual time series belonging to the same Dataflow, identifiable through the DimensionComponents of the Dataflow except the TimeDimension. The coding of these kind of operations might be simplified by mapping distinct time series (i.e. different parts of a SDMX Dataflow) to distinct VTL Data Sets.{{/footnote}}
	390	+As a matter of fact, in some cases it can be useful to define VTL operations involving definite parts of a SDMX Dataflow instead than the whole.^^[[(% 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" %)^^25^^>>path:#sdfootnote25sym||name="sdfootnote25anc"]](%%)^^
375	375
376		-Therefore, in order to make the coding of VTL operations simpler when applied on parts of SDMX Dataflows, it is allowed to map distinct parts of a SDMX Dataflow to distinct VTL Data Sets according to the following rules and conventions. This kind of mapping is possible both from SDMX to VTL and from VTL to SDMX, as better explained below.{{footnote}}Please note that this kind of mapping is only an option at disposal of the definer of VTL Transformations; in fact it remains always possible to manipulate the needed parts of SDMX Dataflows by means of VTL operators (e.g. “sub”, “filter”, “calc”, “union” …), maintaining a mapping one-to-one between SDMX Dataflows and VTL Data Sets.{{/footnote}}
	392	+Therefore, in order to make the coding of VTL operations simpler when applied on parts of SDMX Dataflows, it is allowed to map distinct parts of a SDMX Dataflow to distinct VTL Data Sets according to the following rules and conventions. This kind of mapping is possible both from SDMX to VTL and from VTL to SDMX, as better explained below.^^[[(% 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" %)^^26^^>>path:#sdfootnote26sym||name="sdfootnote26anc"]](%%)^^
377	377
378	378	Given a SDMX Dataflow and some predefined Dimensions of its DataStructure, it is allowed to map the subsets of observations that have the same combination of values for such Dimensions to correspondent VTL datasets.
379	379
380	380	For example, assuming that the SDMX Dataflow DF1(1.0.0) has the Dimensions INDICATOR, TIME_PERIOD and COUNTRY, and that the user declares the Dimensions INDICATOR and COUNTRY as basis for the mapping (i.e. the mapping dimensions): the observations that have the same values for INDICATOR and COUNTRY would be mapped to the same VTL dataset (and vice-versa). In practice, this kind mapping is obtained like follows:
381	381
382		-* For a given SDMX Dataflow, the user (VTL definer) declares the DimensionComponents on which the mapping will be based, in a given order.{{footnote}}This definition is made through the ToVtlSubspace and ToVtlSpaceKey classes and/or the FromVtlSuperspace and FromVtlSpaceKey classes, depending on the direction of the mapping (“key” means “dimension”). The mapping of Dataflow subsets can be applied independently in the two directions, also according to different Dimensions. When no Dimension is declared for a given direction, it is assumed that the option of mapping different parts of a SDMX Dataflow to different VTL Data Sets is not used.{{/footnote}} Following the example above, imagine that the user declares the Dimensions INDICATOR and COUNTRY.
	398	+* For a given SDMX Dataflow, the user (VTL definer) declares the DimensionComponents on which the mapping will be based, in a given order.^^[[(% 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" %)^^27^^>>path:#sdfootnote27sym||name="sdfootnote27anc"]](%%)^^ Following the example above, imagine that the user declares the Dimensions INDICATOR and COUNTRY.
383	383	* The VTL Data Set is given a name using a special notation also called “ordered concatenation” and composed of the following parts:
384	384	** The reference to the SDMX Dataflow (expressed according to the rules described in the previous paragraphs, i.e. URN, abbreviated URN or another alias); for example DF(1.0.0);
385		-** a slash (“/”) as a separator;{{footnote}}As a consequence of this formalism, a slash in the name of the VTL Data Set assumes the specific meaning of separator between the name of the Dataflow and the values of some of its Dimensions.{{/footnote}}
	401	+** a slash (“/”) as a separator; ^^[[(% 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" %)^^28^^>>path:#sdfootnote28sym||name="sdfootnote28anc"]](%%)^^
386	386
387		-The reference to a specific part of the SDMX Dataflow above, expressed as the concatenation of the values that the SDMX DimensionComponents declared above must have, separated by dots (“.”) and written in the order in which these DimensionComponents are defined{{footnote}}This is the order in which the dimensions are defined in the ToVtlSpaceKey class or in the FromVtlSpaceKey class, depending on the direction of the mapping.{{/footnote}}. For example POPULATION.USA would mean that such a VTL Data Set is mapped to the SDMX observations for which the dimension //INDICATOR// is equal to POPULATION and the dimension //COUNTRY// is equal to USA.
	403	+The reference to a specific part of the SDMX Dataflow above, expressed as the concatenation of the values that the SDMX DimensionComponents declared above must have, separated by dots (“.”) and written in the order in which these DimensionComponents are defined^^[[(% 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" %)^^29^^>>path:#sdfootnote29sym||name="sdfootnote29anc"]](%%)^^. For example POPULATION.USA would mean that such a VTL Data Set is mapped to the SDMX observations for which the dimension //INDICATOR// is equal to POPULATION and the dimension //COUNTRY// is equal to USA.
388	388
389	389	In the VTL Transformations, this kind of dataset name must be referenced between single quotes because the slash (“/”) is not a regular character according to the VTL rules.
390	390
...	...	@@ -400,7 +400,7 @@
400	400
401	401	Let us now analyse the different meaning of this kind of mapping in the two mapping directions, i.e. from SDMX to VTL and from VTL to SDMX.
402	402
403		-As already said, the mapping from SDMX to VTL happens when the SDMX dataflows are operand of VTL Transformations, instead the mapping from VTL to SDMX happens when the VTL Data Sets that is result of Transformations{{footnote}}It should be remembered that, according to the VTL consistency rules, a given VTL dataset cannot be the result of more than one VTL Transformation.{{/footnote}} need to be treated as SDMX objects. This kind of mapping can be applied independently in the two directions and the Dimensions on which the mapping is based can be different in the two directions: these Dimensions are defined in the ToVtlSpaceKey and in the FromVtlSpaceKey classes respectively.
	419	+As already said, the mapping from SDMX to VTL happens when the SDMX dataflows are operand of VTL Transformations, instead the mapping from VTL to SDMX happens when the VTL Data Sets that is result of Transformations^^[[(% 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" %)^^30^^>>path:#sdfootnote30sym||name="sdfootnote30anc"]](%%)^^ need to be treated as SDMX objects. This kind of mapping can be applied independently in the two directions and the Dimensions on which the mapping is based can be different in the two directions: these Dimensions are defined in the ToVtlSpaceKey and in the FromVtlSpaceKey classes respectively.
404	404
405	405	First, let us see what happens in the __mapping direction from SDMX to VTL__, i.e. when parts of a SDMX Dataflow (e.g. DF1(1.0.0)) need to be mapped to distinct VTL Data Sets that are operand of some VTL Transformations.
406	406
...	...	@@ -408,16 +408,28 @@
408	408
409	409	SDMX Dataflow having INDICATOR=//INDICATORvalue //and COUNTRY=// COUNTRYvalue//. For example, the VTL dataset ‘DF1(1.0.0)/POPULATION.USA’ would contain all the observations of DF1(1.0.0) having INDICATOR = POPULATION and COUNTRY = USA.
410	410
411		-In order to obtain the data structure of these VTL Data Sets from the SDMX one, it is assumed that the SDMX DimensionComponents on which the mapping is based are dropped, i.e. not maintained in the VTL data structure; this is possible because their values are fixed for each one of the invoked VTL Data Sets{{footnote}}If these DimensionComponents would not be dropped, the various VTL Data Sets resulting from this kind of mapping would have non-matching values for the Identifiers corresponding to the mapping Dimensions (e.g. POPULATION and COUNTRY). As a consequence, taking into account that the typical binary VTL operations at dataset level (+, -, *, / and so on) are executed on the observations having matching values for the identifiers, it would not be possible to compose the resulting VTL datasets one another (e.g. it would not be possible to calculate the population ratio between USA and CANADA).{{/footnote}}. After that, the mapping method from SDMX to VTL specified for the Dataflow DF1(1.0.0) is applied (i.e. basic, pivot …).
	427	+In order to obtain the data structure of these VTL Data Sets from the SDMX one, it is assumed that the SDMX DimensionComponents on which the mapping is based are dropped, i.e. not maintained in the VTL data structure; this is possible because their values are fixed for each one of the invoked VTL Data Sets^^[[(% 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" %)^^31^^>>path:#sdfootnote31sym||name="sdfootnote31anc"]](%%)^^. After that, the mapping method from SDMX to VTL specified for the Dataflow DF1(1.0.0) is applied (i.e.
412	412
413		-In the example above, for all the datasets of the kind ‘DF1(1.0.0)///INDICATORvalue//.//COUNTRYvalue//’, the dimensions INDICATOR and COUNTRY would be dropped so that the data structure of all the resulting VTL Data Sets would have the identifier TIME_PERIOD only.
	429	+basic, pivot …).
414	414
	431	+In the example above, for all the datasets of the kind
	432	+
	433	+‘DF1(1.0.0)///INDICATORvalue//.//COUNTRYvalue//’, the dimensions INDICATOR and COUNTRY would be dropped so that the data structure of all the resulting VTL Data Sets would have the identifier TIME_PERIOD only.
	434	+
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		-[[image:1747388275998-621.png]]
	437	+‘DF1(1.0.0)/POPULATION.USA’ :=
418	418
419		-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}}
	439	+DF1(1.0.0) [ sub INDICATOR=“POPULATION”, COUNTRY=“USA” ];
420	420
	441	+‘DF1(1.0.0)/POPULATION.CANADA’ :=
	442	+
	443	+DF1(1.0.0) [ sub INDICATOR=“POPULATION”, COUNTRY=“CANADA” ];
	444	+
	445	+… … …
	446	+
	447	+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" %)^^32^^>>path:#sdfootnote32sym||name="sdfootnote32anc"]](%%)^^
	448	+
421	421	In the direction from SDMX to VTL it is allowed to omit the value of one or more
422	422
423	423	DimensionComponents on which the mapping is based, but maintaining all the separating dots (therefore it may happen to find two or more consecutive dots and dots in the beginning or in the end). The absence of value means that for the corresponding Dimension all the values are kept and the Dimension is not dropped.
...	...	@@ -426,8 +426,10 @@
426	426
427	427	This is equivalent to the application of the VTL “sub” operator only to the identifier //INDICATOR//:
428	428
429		-[[image:1747388244829-693.png]]
	457	+‘DF1(1.0.0)/POPULATION.’ :=
430	430
	459	+DF1(1.0.0) [ sub INDICATOR=“POPULATION” ];
	460	+
431	431	Therefore the VTL Data Set ‘DF1(1.0.0)/POPULATION.’ would have the identifiers COUNTRY and TIME_PERIOD.
432	432
433	433	Heterogeneous invocations of the same Dataflow are allowed, i.e. omitting different
...	...	@@ -442,34 +442,70 @@
442	442
443	443	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:
444	444
445		-* each part is calculated as a VTL derived Data Set, result of a dedicated VTL Transformation;{{footnote}}If the whole DF2(1.0) is calculated by means of just one VTL Transformation, then the mapping between the SDMX Dataflow and the corresponding VTL dataset is one-to-one and this kind of mapping (one SDMX Dataflow to many VTL datasets) does not apply.{{/footnote}}
446		-* the data structure of all these VTL Data Sets has the TIME_PERIOD identifier and does not have the INDICATOR and COUNTRY identifiers.{{footnote}}This is possible as each VTL dataset corresponds to one particular combination of values of INDICATOR and COUNTRY.{{/footnote}}
	475	+* 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" %)^^33^^>>path:#sdfootnote33sym||name="sdfootnote33anc"]](%%)^^
	476	+* 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" %)^^34^^>>path:#sdfootnote34sym||name="sdfootnote34anc"]](%%)^^
447	447
448		-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}}The mapping dimensions are defined as FromVtlSpaceKeys of the FromVtlSuperSpace of the VtlDataflowMapping relevant to DF2(1.0).{{/footnote}}.
	478	+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" %)^^35^^>>path:#sdfootnote35sym||name="sdfootnote35anc"]](%%)^^.
449	449
450		-The corresponding VTL 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}}
	480	+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" %)^^36^^>>path:#sdfootnote36sym||name="sdfootnote36anc"]](%%)^^
451	451
452	452	‘DF2(1.0.0)/INDICATORvalue.COUNTRYvalue’ <- expression
453	453
454	454	Some examples follow, for some specific values of INDICATOR and COUNTRY:
455	455
456		-[[image:1747388222879-916.png]]
	486	+‘DF2(1.0.0)/GDPPERCAPITA.USA’ <- expression11; ‘DF2(1.0.0)/GDPPERCAPITA.CANADA’ <- expression12;
457	457
458		-[[image:1747388206717-256.png]]
	488	+… … …
459	459
	490	+‘DF2(1.0.0)/POPGROWTH.USA’ <- expression21;
	491	+
	492	+‘DF2(1.0.0)/POPGROWTH.CANADA’ <- expression22;
	493	+
	494	+… … …
	495	+
460	460	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:
461	461
462		-[[image:1747388148322-387.png]]
	498	+VTL dataset INDICATOR value COUNTRY value
463	463
	500	+‘DF2(1.0.0)/GDPPERCAPITA.USA’ GDPPERCAPITA USA
	501	+
	502	+‘DF2(1.0.0)/GDPPERCAPITA.CANADA’ GDPPERCAPITA CANADA … … …
	503	+
	504	+‘DF2(1.0.0)/POPGROWTH.USA’ POPGROWTH USA
	505	+
	506	+‘DF2(1.0.0)/POPGROWTH.CANADA’ POPGROWTH CANADA
	507	+
	508	+… … …
	509	+
464	464	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:
465	465
466		-[[image:1747388179021-814.png]]
	512	+DF2bis_GDPPERCAPITA_USA := ‘DF2(1.0.0)/GDPPERCAPITA.USA’ [calc identifier INDICATOR := ”GDPPERCAPITA”, identifier COUNTRY := ”USA”];
467	467
	514	+DF2bis_GDPPERCAPITA_CANADA := ‘DF2(1.0.0)/GDPPERCAPITA.CANADA’ [calc identifier INDICATOR:=”GDPPERCAPITA”, identifier COUNTRY:=”CANADA”]; … … …
	515	+
	516	+DF2bis_POPGROWTH_USA := ‘DF2(1.0.0)/POPGROWTH.USA’
	517	+
	518	+[calc identifier INDICATOR := ”POPGROWTH”, identifier COUNTRY := ”USA”];
	519	+
	520	+DF2bis_POPGROWTH_CANADA’ := ‘DF2(1.0.0)/POPGROWTH.CANADA’ [calc identifier INDICATOR := ”POPGROWTH”, identifier COUNTRY := ”CANADA”]; … … …
	521	+
	522	+DF2(1.0) <- UNION (DF2bis_GDPPERCAPITA_USA’,
	523	+
	524	+DF2bis_GDPPERCAPITA_CANADA’,
	525	+
	526	+… ,
	527	+
	528	+DF2bis_POPGROWTH_USA’,
	529	+
	530	+DF2bis_POPGROWTH_CANADA’
	531	+
	532	+…);
	533	+
468	468	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
469	469
470		-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.
	536	+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" %)^^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.
471	471
472		-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}}In case the ordered concatenation notation from VTL to SDMX is used, the set of Transformations described above is implicitly performed; therefore, in order to test the overall compliance of the VTL program to the VTL consistency rules, these implicit Transformations have to be considered as part of the VTL program even if they are not explicitly coded.{{/footnote}}
	538	+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" %)^^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" %)^^39^^>>path:#sdfootnote39sym||name="sdfootnote39anc"]](%%)^^
473	473
474	474	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).
475	475
...	...	@@ -477,43 +477,52 @@
477	477
478	478	With reference to the VTL “model for Variables and Value domains”, the following additional mappings have to be considered:
479	479
480		-(% style="width:895.294px" %)
481		-|(% style="width:278px" %)**VTL**|(% style="width:613px" %)**SDMX**
482		-|(% style="width:278px" %)**Data Set Component**|(% style="width:613px" %)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:278px" %)**Represented Variable**|(% style="width:613px" %)(((
	546	+|VTL|SDMX
	547	+|**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^^
	548	+|**Represented Variable**|(((
484	484	**Concept** with a definite
485	485
486	486	Representation
487	487	)))
488		-|(% style="width:278px" %)**Value Domain**|(% style="width:613px" %)(((
489		-**Representation** (see the Structure Pattern in the Base Package)
	553	+|**Value Domain**|(((
	554	+**Representation** (see the Structure
	555	+
	556	+Pattern in the Base Package)
490	490	)))
491		-|(% style="width:278px" %)**Enumerated Value Domain /
492		-Code List**|(% style="width:613px" %)**Codelist**
493		-|(% style="width:278px" %)**Code**|(% style="width:613px" %)(((
494		-**Code** (for enumerated DimensionComponent, Measure, DataAttribute)
	558	+|**Enumerated Value Domain / Code List**|**Codelist**
	559	+|**Code**|(((
	560	+**Code** (for enumerated
	561	+
	562	+DimensionComponent, Measure, DataAttribute)
495	495	)))
496		-|(% style="width:278px" %)**Described Value Domain**|(% style="width:613px" %)(((
497		-non-enumerated** Representation **(having Facets / ExtendedFacets, see the Structure Pattern in the Base Package)
	564	+|**Described Value Domain**|(((
	565	+non-enumerated** &nbsp;&nbsp;&nbsp;Representation**
	566	+
	567	+(having Facets / ExtendedFacets, see the Structure Pattern in the Base Package)
498	498	)))
499		-|(% style="width:278px" %)**Value**|(% style="width:613px" %)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)
500		-|(% style="width:278px" %)**Value Domain Subset / Set**|(% style="width:613px" %)This abstraction does not exist in SDMX
501		-|(% style="width:278px" %)**Enumerated Value Domain Subset / Enumerated Set**|(% style="width:613px" %)This abstraction does not exist in SDMX
502		-|(% style="width:278px" %)**Described Value Domain Subset / Described Set**|(% style="width:613px" %)This abstraction does not exist in SDMX
503		-|(% style="width:278px" %)**Set list**|(% style="width:613px" %)This abstraction does not exist in SDMX
	569	+|**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
	570	+| |(((
	571	+to a valid **value &nbsp;&nbsp;&nbsp;**(for non-enumerated** &nbsp;&nbsp;&nbsp;**
504	504
	573	+Representations)
	574	+)))
	575	+|**Value Domain Subset / Set**|This abstraction does not exist in SDMX
	576	+|**Enumerated Value Domain Subset / Enumerated Set**|This abstraction does not exist in SDMX
	577	+|**Described Value Domain Subset / Described Set**|This abstraction does not exist in SDMX
	578	+|**Set list**|This abstraction does not exist in SDMX
	579	+
505	505	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).
506	506
507		-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 using represented variables, VTL can assume that data structures having the same variables as identifiers can be composed one another because the correspondent values can match.{{/footnote}}, while the SDMX Concepts can have different Representations in different DataStructures.{{footnote}}A Concept becomes a Component in a DataStructureDefinition, and Components can have different LocalRepresentations in different DataStructureDefinitions, also overriding the (possible) base representation of the Concept.{{/footnote}} This means that one SDMX Concept can correspond to many VTL Variables, one for each representation the Concept has.
	582	+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" %)^^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" %)^^41^^>>path:#sdfootnote41sym||name="sdfootnote41anc"]](%%)^^ This means that one SDMX Concept can correspond to many VTL Variables, one for each representation the Concept has.
508	508
509	509	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
510	510
511		-DS_c := DS_a + DS_b (where DS_a, DS_b, DS_c are VTL Data Sets)
	586	+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.
512	512
513		-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.
514		-
515	515	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
516	516
	590	+[[image:SDMX 3-0-0 SECTION 6 FINAL-1.0_en_59eee18f.gif||alt="Shape5" height="1" width="192"]]
	591	+
517	517	Transformations to ensure that the VTL expressions are consistent with the actual representations of the correspondent SDMX Concepts.
518	518
519	519	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.
...	...	@@ -526,19 +526,140 @@
526	526
527	527	The VTL data types are sub-divided in scalar types (like integers, strings, etc.), which are the types of the scalar values, and compound types (like Data Sets, Components, Rulesets, etc.), which are the types of the compound structures. See below the diagram of the VTL data types, taken from the VTL User Manual:
528	528
529		-[[image:1747388434672-948.png]]
	604	+[[image:SDMX 3-0-0 SECTION 6 FINAL-1.0_en_e3df33ae.png||height="543" width="483"]]
530	530
531		-(% class="wikigeneratedid" id="HFigure222013VTLDataTypes" %)
532		-**Figure 22 – VTL Data Types**
	606	+==== Figure 22 – VTL Data Types ====
533	533
534	534	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.
535	535
536	536	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):
537	537
538		-[[image:1747388465321-274.png]]
539	539
540		-**Figure 23 – VTL Basic Scalar Types**
541	541
	614	+(((
	615	+//n//
	616	+
	617	+//a//
	618	+
	619	+//e//
	620	+
	621	+//l//
	622	+
	623	+//o//
	624	+
	625	+//o//
	626	+
	627	+//B//
	628	+
	629	+//n//
	630	+
	631	+//o//
	632	+
	633	+//i//
	634	+
	635	+//t//
	636	+
	637	+//a//
	638	+
	639	+//r//
	640	+
	641	+//u//
	642	+
	643	+//D//
	644	+
	645	+//d//
	646	+
	647	+//o//
	648	+
	649	+//i//
	650	+
	651	+//r//
	652	+
	653	+//e//
	654	+
	655	+//p//
	656	+
	657	+//_//
	658	+
	659	+//e//
	660	+
	661	+//m//
	662	+
	663	+//i//
	664	+
	665	+//T//
	666	+
	667	+//e//
	668	+
	669	+//t//
	670	+
	671	+//a//
	672	+
	673	+//D//
	674	+
	675	+//e//
	676	+
	677	+//m//
	678	+
	679	+//i//
	680	+
	681	+//T//
	682	+
	683	+//r//
	684	+
	685	+//e//
	686	+
	687	+//g//
	688	+
	689	+//e//
	690	+
	691	+//t//
	692	+
	693	+//n//
	694	+
	695	+//I//
	696	+
	697	+//r//
	698	+
	699	+//e//
	700	+
	701	+//b//
	702	+
	703	+//m//
	704	+
	705	+//u//
	706	+
	707	+//N//
	708	+
	709	+//g//
	710	+
	711	+//n//
	712	+
	713	+//i//
	714	+
	715	+//r//
	716	+
	717	+//t//
	718	+
	719	+//S//
	720	+
	721	+//r//
	722	+
	723	+//a//
	724	+
	725	+//l//
	726	+
	727	+//a//
	728	+
	729	+//c//
	730	+
	731	+//S//
	732	+
	733	+[[image:SDMX 3-0-0 SECTION 6 FINAL-1.0_en_82d45833.gif||alt="Shape6" height="231" width="184"]]
	734	+)))
	735	+
	736	+==== Figure 23 – VTL Basic Scalar Types ====
	737	+
542	542	=== 12.4.2 VTL basic scalar types and SDMX data types ===
543	543
544	544	The VTL assumes that a basic scalar type has a unique internal representation and can have more external representations.
...	...	@@ -561,159 +561,204 @@
561	561
562	562	The following table describes the default mapping for converting from the SDMX data types to the VTL basic scalar types.
563	563
564		-(% style="width:823.294px" %)
565		-|(% style="width:509px" %)**SDMX data type (BasicComponentDataType)**|(% style="width:312px" %)**Default VTL basic scalar type**
566		-|(% style="width:509px" %)(((
	760	+|SDMX data type (BasicComponentDataType)|Default VTL basic scalar type
	761	+|(((
567	567	String
	763	+
568	568	(string allowing any character)
569		-)))|(% style="width:312px" %)string
570		-|(% style="width:509px" %)(((
	765	+)))|string
	766	+|(((
571	571	Alpha
	768	+
572	572	(string which only allows A-z)
573		-)))|(% style="width:312px" %)string
574		-|(% style="width:509px" %)(((
	770	+)))|string
	771	+|(((
575	575	AlphaNumeric
	773	+
576	576	(string which only allows A-z and 0-9)
577		-)))|(% style="width:312px" %)string
578		-|(% style="width:509px" %)(((
	775	+)))|string
	776	+|(((
579	579	Numeric
	778	+
580	580	(string which only allows 0-9, but is not numeric so that is can having leading zeros)
581		-)))|(% style="width:312px" %)string
582		-|(% style="width:509px" %)(((
	780	+)))|string
	781	+|(((
583	583	BigInteger
	783	+
584	584	(corresponds to XML Schema xs:integer datatype; infinite set of integer values)
585		-)))|(% style="width:312px" %)integer
586		-|(% style="width:509px" %)(((
	785	+)))|integer
	786	+|(((
587	587	Integer
588		-(corresponds to XML Schema xs:int datatype; between -2147483648 and +2147483647 (inclusive))
589		-)))|(% style="width:312px" %)integer
590		-|(% style="width:509px" %)(((
	788	+
	789	+(corresponds to XML Schema xs:int datatype; between -2147483648 and +2147483647
	790	+
	791	+(inclusive))
	792	+)))|integer
	793	+|(((
591	591	Long
592		-(corresponds to XML Schema xs:long datatype; between -9223372036854775808 and +9223372036854775807 (inclusive))
593		-)))|(% style="width:312px" %)integer
594		-|(% style="width:509px" %)(((
	795	+
	796	+(corresponds to XML Schema xs:long datatype; between -9223372036854775808 and
	797	+
	798	++9223372036854775807 (inclusive))
	799	+)))|integer
	800	+|(((
595	595	Short
	802	+
596	596	(corresponds to XML Schema xs:short datatype; between -32768 and -32767 (inclusive))
597		-)))|(% style="width:312px" %)integer
598		-|(% style="width:509px" %)Decimal (corresponds to XML Schema xs:decimal datatype; subset of real numbers that can be represented as decimals)|(% style="width:312px" %)number
599		-|(% style="width:509px" %)(((
	804	+)))|integer
	805	+|Decimal (corresponds to XML Schema xs:decimal datatype; subset of real numbers that can be represented as decimals)|number
	806	+|(((
600	600	Float
	808	+
601	601	(corresponds to XML Schema xs:float datatype; patterned after the IEEE single-precision 32-bit floating point type)
602		-)))|(% style="width:312px" %)number
603		-|(% style="width:509px" %)(((
	810	+)))|number
	811	+|(((
604	604	Double
	813	+
605	605	(corresponds to XML Schema xs:double datatype; patterned after the IEEE double-precision 64-bit floating point type)
606		-)))|(% style="width:312px" %)number
607		-|(% style="width:509px" %)(((
	815	+)))|number
	816	+|(((
608	608	Boolean
609		-(corresponds to the XML Schema xs:boolean datatype; support the mathematical concept of binary-valued logic: {true, false})
610		-)))|(% style="width:312px" %)boolean
611	611
612		-(% style="width:822.294px" %)
613		-|(% colspan="2" style="width:507px" %)(((
	819	+(corresponds to the XML Schema xs:boolean datatype; support the mathematical concept of
	820	+
	821	+binary-valued logic: {true, false})
	822	+)))|boolean
	823	+
	824	+| |(% colspan="2" %)(((
614	614	URI
	826	+
615	615	(corresponds to the XML Schema xs:anyURI; absolute or relative Uniform Resource Identifier Reference)
616		-)))|(% colspan="1" style="width:311px" %)string
617		-|(% colspan="2" style="width:507px" %)(((
	828	+)))|(% colspan="2" %)string
	829	+| |(% colspan="2" %)(((
618	618	Count
	831	+
619	619	(an integer following a sequential pattern, increasing by 1 for each occurrence)
620		-)))|(% colspan="1" style="width:311px" %)integer
621		-|(% colspan="2" style="width:507px" %)(((
	833	+)))|(% colspan="2" %)integer
	834	+| |(% colspan="2" %)(((
622	622	InclusiveValueRange
	836	+
623	623	(decimal number within a closed interval, whose bounds are specified in the SDMX representation by the facets minValue and maxValue)
624		-)))|(% colspan="1" style="width:311px" %)number
625		-|(% colspan="2" style="width:507px" %)(((
	838	+)))|(% colspan="2" %)number
	839	+| |(% colspan="2" %)(((
626	626	ExclusiveValueRange
	841	+
627	627	(decimal number within an open interval, whose bounds are specified in the SDMX representation by the facets minValue and maxValue)
628		-)))|(% colspan="1" style="width:311px" %)number
629		-|(% colspan="2" style="width:507px" %)(((
	843	+)))|(% colspan="2" %)number
	844	+| |(% colspan="2" %)(((
630	630	Incremental
	846	+
631	631	(decimal number the increased by a specific interval (defined by the interval facet), which is typically enforced outside of the XML validation)
632		-)))|(% colspan="1" style="width:311px" %)number
633		-|(% colspan="2" style="width:507px" %)(((
	848	+)))|(% colspan="2" %)number
	849	+| |(% colspan="2" %)(((
634	634	ObservationalTimePeriod
	851	+
635	635	(superset of StandardTimePeriod and TimeRange)
636		-)))|(% colspan="1" style="width:311px" %)time
637		-|(% colspan="2" style="width:507px" %)(((
	853	+)))|(% colspan="2" %)time
	854	+| |(% colspan="2" %)(((
638	638	StandardTimePeriod
639		-(superset of BasicTimePeriod and ReportingTimePeriod)
640		-)))|(% colspan="1" style="width:311px" %)time
641		-|(% colspan="2" style="width:507px" %)(((
	856	+
	857	+(superset of BasicTimePeriod and
	858	+
	859	+ReportingTimePeriod)
	860	+)))|(% colspan="2" %)time
	861	+| |(% colspan="2" %)(((
642	642	BasicTimePeriod
	863	+
643	643	(superset of GregorianTimePeriod and DateTime)
644		-)))|(% colspan="1" style="width:311px" %)date
645		-|(% colspan="2" style="width:507px" %)(((
	865	+)))|(% colspan="2" %)date
	866	+| |(% colspan="2" %)(((
646	646	GregorianTimePeriod
	868	+
647	647	(superset of GregorianYear, GregorianYearMonth, and GregorianDay)
648		-)))|(% colspan="1" style="width:311px" %)date
649		-|(% colspan="2" style="width:507px" %)GregorianYear (YYYY)|(% colspan="1" style="width:311px" %)date
650		-|(% colspan="2" style="width:507px" %)GregorianYearMonth / GregorianMonth (YYYY-MM)|(% colspan="1" style="width:311px" %)date
651		-|(% colspan="2" style="width:507px" %)GregorianDay (YYYY-MM-DD)|(% colspan="1" style="width:311px" %)date
652		-|(% colspan="2" style="width:507px" %)(((
	870	+)))|(% colspan="2" %)date
	871	+| |(% colspan="2" %)GregorianYear (YYYY)|(% colspan="2" %)date
	872	+| |(% colspan="2" %)GregorianYearMonth / GregorianMonth (YYYY-MM)|(% colspan="2" %)date
	873	+| |(% colspan="2" %)GregorianDay (YYYY-MM-DD)|(% colspan="2" %)date
	874	+| |(% colspan="2" %)(((
653	653	ReportingTimePeriod
654		-(superset of RepostingYear, ReportingSemester, ReportingTrimester, ReportingQuarter, ReportingMonth, ReportingWeek, ReportingDay)
655		-)))|(% colspan="1" style="width:311px" %)time_period
656		-|(% colspan="2" style="width:507px" %)(((
	876	+
	877	+(superset of RepostingYear, ReportingSemester,
	878	+
	879	+ReportingTrimester, ReportingQuarter,
	880	+
	881	+ReportingMonth, ReportingWeek, ReportingDay)
	882	+)))|(% colspan="2" %)time_period
	883	+| |(% colspan="2" %)(((
657	657	ReportingYear
	885	+
658	658	(YYYY-A1 – 1 year period)
659		-)))|(% colspan="1" style="width:311px" %)time_period
660		-|(% colspan="2" style="width:507px" %)(((
	887	+)))|(% colspan="2" %)time_period
	888	+| |(% colspan="2" %)(((
661	661	ReportingSemester
	890	+
662	662	(YYYY-Ss – 6 month period)
663		-)))|(% colspan="1" style="width:311px" %)time_period
664		-|(% colspan="2" style="width:507px" %)(((
	892	+)))|(% colspan="2" %)time_period
	893	+| |(% colspan="2" %)(((
665	665	ReportingTrimester
	895	+
666	666	(YYYY-Tt – 4 month period)
667		-)))|(% colspan="1" style="width:311px" %)time_period
668		-|(% colspan="2" style="width:507px" %)(((
	897	+)))|(% colspan="2" %)time_period
	898	+| |(% colspan="2" %)(((
669	669	ReportingQuarter
	900	+
670	670	(YYYY-Qq – 3 month period)
671		-)))|(% colspan="1" style="width:311px" %)time_period
672		-|(% colspan="2" style="width:507px" %)(((
	902	+)))|(% colspan="2" %)time_period
	903	+| |(% colspan="2" %)(((
673	673	ReportingMonth
	905	+
674	674	(YYYY-Mmm – 1 month period)
675		-)))|(% colspan="1" style="width:311px" %)time_period
676		-|(% colspan="2" style="width:507px" %)ReportingWeek|(% colspan="1" style="width:311px" %)time_period
677		-|(% 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" %)
678		-|(% colspan="1" style="width:507px" %)(((
	907	+)))|(% colspan="2" %)time_period
	908	+| |(% colspan="2" %)ReportingWeek|(% colspan="2" %)time_period
	909	+| |(% colspan="2" %) |(% colspan="2" %)
	910	+| |(% colspan="2" %) |(% colspan="2" %)
	911	+|(% colspan="2" %)(YYYY-Www – 7 day period; following ISO 8601 definition of a week in a year)|(% colspan="2" %) |
	912	+|(% colspan="2" %)(((
679	679	ReportingDay
	914	+
680	680	(YYYY-Dddd – 1 day period)
681		-)))|(% colspan="2" style="width:312px" %)time_period
682		-|(% colspan="1" style="width:507px" %)(((
	916	+)))|(% colspan="2" %)time_period|
	917	+|(% colspan="2" %)(((
683	683	DateTime
	919	+
684	684	(YYYY-MM-DDThh:mm:ss)
685		-)))|(% colspan="2" style="width:312px" %)date
686		-|(% colspan="1" style="width:507px" %)(((
	921	+)))|(% colspan="2" %)date|
	922	+|(% colspan="2" %)(((
687	687	TimeRange
	924	+
688	688	(YYYY-MM-DD(Thh:mm:ss)?/<duration>)
689		-)))|(% colspan="2" style="width:312px" %)time
690		-|(% colspan="1" style="width:507px" %)(((
	926	+)))|(% colspan="2" %)time|
	927	+|(% colspan="2" %)(((
691	691	Month
	929	+
692	692	(~-~-MM; speicifies a month independent of a year; e.g. February is black history month in the United States)
693		-)))|(% colspan="2" style="width:312px" %)string
694		-|(% colspan="1" style="width:507px" %)(((
	931	+)))|(% colspan="2" %)string|
	932	+|(% colspan="2" %)(((
695	695	MonthDay
	934	+
696	696	(~-~-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)
697		-)))|(% colspan="2" style="width:312px" %)string
698		-|(% colspan="1" style="width:507px" %)(((
	936	+)))|(% colspan="2" %)string|
	937	+|(% colspan="2" %)(((
699	699	Day
	939	+
700	700	(~-~--DD; specifies a day independent of a month or year; e.g. the 15^^th^^ is payday)
701		-)))|(% colspan="2" style="width:312px" %)string
702		-|(% colspan="1" style="width:507px" %)(((
	941	+)))|(% colspan="2" %)string|
	942	+|(% colspan="2" %)(((
703	703	Time
	944	+
704	704	(hh:mm:ss; time independent of a date; e.g. coffee break is at 10:00 AM)
705		-)))|(% colspan="2" style="width:312px" %)string
706		-|(% colspan="1" style="width:507px" %)(((
	946	+)))|(% colspan="2" %)string|
	947	+|(% colspan="2" %)(((
707	707	Duration
	949	+
708	708	(corresponds to XML Schema xs:duration datatype)
709		-)))|(% colspan="2" style="width:312px" %)duration
710		-|(% colspan="1" style="width:507px" %)XHTML|(% colspan="2" style="width:312px" %)Metadata type – not applicable
711		-|(% colspan="1" style="width:507px" %)KeyValues|(% colspan="2" style="width:312px" %)Metadata type – not applicable
712		-|(% colspan="1" style="width:507px" %)IdentifiableReference|(% colspan="2" style="width:312px" %)Metadata type – not applicable
713		-|(% colspan="1" style="width:507px" %)DataSetReference|(% colspan="2" style="width:312px" %)Metadata type – not applicable
	951	+)))|(% colspan="2" %)duration|
	952	+|(% colspan="2" %)XHTML|(% colspan="2" %)Metadata type – not applicable|
	953	+|(% colspan="2" %)KeyValues|(% colspan="2" %)Metadata type – not applicable|
	954	+|(% colspan="2" %)IdentifiableReference|(% colspan="2" %)Metadata type – not applicable|
	955	+|(% colspan="2" %)DataSetReference|(% colspan="2" %)Metadata type – not applicable|
714	714
715		-(% class="wikigeneratedid" id="HFigure142013MappingsfromSDMXdatatypestoVTLBasicScalarTypes" %)
716		-**Figure 14 – Mappings from SDMX data types to VTL Basic Scalar Types**
	957	+==== Figure 14 – Mappings from SDMX data types to VTL Basic Scalar Types ====
717	717
718	718	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).
719	719
...	...	@@ -721,86 +721,93 @@
721	721
722	722	The following table describes the default conversion from the VTL basic scalar types to the SDMX data types .
723	723
724		-(% style="width:1073.29px" %)
725		-|(% style="width:207px" %)(((
726		-**VTL basic scalar type**
727		-)))|(% style="width:462px" %)(((
728		-**Default SDMX data type (BasicComponentDataType)**
729		-)))|(% style="width:402px" %)**Default output format**
730		-|(% style="width:207px" %)String|(% style="width:462px" %)String|(% style="width:402px" %)Like XML (xs:string)
731		-|(% style="width:207px" %)Number|(% style="width:462px" %)Float|(% style="width:402px" %)Like XML (xs:float)
732		-|(% style="width:207px" %)Integer|(% style="width:462px" %)Integer|(% style="width:402px" %)Like XML (xs:int)
733		-|(% style="width:207px" %)Date|(% style="width:462px" %)DateTime|(% style="width:402px" %)YYYY-MM-DDT00:00:00Z
734		-|(% style="width:207px" %)Time|(% style="width:462px" %)StandardTimePeriod|(% style="width:402px" %)<date>/<date> (as defined above)
735		-|(% style="width:207px" %)time_period|(% style="width:462px" %)(((
	965	+|(((
	966	+VTL basic
	967	+
	968	+scalar type
	969	+)))|(((
	970	+Default SDMX data type
	971	+
	972	+(BasicComponentDataType
	973	+
	974	+)
	975	+)))|Default output format
	976	+|String|String|Like XML (xs:string)
	977	+|Number|Float|Like XML (xs:float)
	978	+|Integer|Integer|Like XML (xs:int)
	979	+|Date|DateTime|YYYY-MM-DDT00:00:00Z
	980	+|Time|StandardTimePeriod|<date>/<date> (as defined above)
	981	+|time_period|(((
736	736	ReportingTimePeriod
	983	+
737	737	(StandardReportingPeriod)
738		-)))|(% style="width:402px" %)(((
	985	+)))|(((
739	739	YYYY-Pppp
	987	+
740	740	(according to SDMX )
741	741	)))
742		-|(% style="width:207px" %)Duration|(% style="width:462px" %)Duration|(% style="width:402px" %)(((
	990	+|Duration|Duration|(((
743	743	Like XML (xs:duration)
	992	+
744	744	PnYnMnDTnHnMnS
745	745	)))
746		-|(% style="width:207px" %)Boolean|(% style="width:462px" %)Boolean|(% style="width:402px" %)Like XML (xs:boolean) with the values "true" or "false"
	995	+|Boolean|Boolean|Like XML (xs:boolean) with the values "true" or "false"
747	747
748		-(% class="wikigeneratedid" id="HFigure142013MappingsfromSDMXdatatypestoVTLBasicScalarTypes-1" %)
749		-**Figure 14 – Mappings from SDMX data types to VTL Basic Scalar Types**
	997	+==== Figure 14 – Mappings from SDMX data types to VTL Basic Scalar Types ====
750	750
751	751	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).
752	752
753	753	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.
754	754
755		-(% style="width:713.294px" %)
756		-|(% colspan="2" style="width:710px" %)VTL special characters for the formatting masks
757		-|(% colspan="2" style="width:710px" %)
758		-|(% colspan="2" style="width:710px" %)Number
759		-|D|(% style="width:486px" %)one numeric digit (if the scientific notation is adopted, D is only for the mantissa)
760		-|E|(% style="width:486px" %)one numeric digit (for the exponent of the scientific notation)
761		-|. (dot)|(% style="width:486px" %)possible separator between the integer and the decimal parts.
762		-|, (comma)|(% style="width:486px" %)possible separator between the integer and the decimal parts.
763		-| |(% style="width:486px" %)
764		-|(% colspan="2" style="width:710px" %)Time and duration
765		-|C|(% style="width:486px" %)century
766		-|Y|(% style="width:486px" %)year
767		-|S|(% style="width:486px" %)semester
768		-|Q|(% style="width:486px" %)quarter
769		-|M|(% style="width:486px" %)month
770		-|W|(% style="width:486px" %)week
771		-|D|(% style="width:486px" %)day
772		-|h|(% style="width:486px" %)hour digit (by default on 24 hours)
773		-|M|(% style="width:486px" %)minute
774		-|S|(% style="width:486px" %)second
775		-|D|(% style="width:486px" %)decimal of second
776		-|P|(% style="width:486px" %)period indicator (representation in one digit for the duration)
777		-|P|(% style="width:486px" %)number of the periods specified in the period indicator
778		-|AM/PM|(% style="width:486px" %)indicator of AM / PM (e.g. am/pm for "am" or "pm")
779		-|MONTH|(% style="width:486px" %)uppercase textual representation of the month (e.g., JANUARY for January)
780		-|DAY|(% style="width:486px" %)uppercase textual representation of the day (e.g., MONDAY for Monday)
781		-|Month|(% style="width:486px" %)lowercase textual representation of the month (e.g., january)
782		-|Day|(% style="width:486px" %)lowercase textual representation of the month (e.g., monday)
783		-|Month|(% style="width:486px" %)First character uppercase, then lowercase textual representation of the month (e.g., January)
784		-|Day|(% style="width:486px" %)First character uppercase, then lowercase textual representation of the day using (e.g. Monday)
785		-| |(% style="width:486px" %)
786		-|(% colspan="2" style="width:710px" %)String
787		-|X|(% style="width:486px" %)any string character
788		-|Z|(% style="width:486px" %)any string character from "A" to "z"
789		-|9|(% style="width:486px" %)any string character from "0" to "9"
790		-| |(% style="width:486px" %)
791		-|(% colspan="2" style="width:710px" %)Boolean
792		-|B|(% style="width:486px" %)Boolean using "true" for True and "false" for False
793		-|1|(% style="width:486px" %)Boolean using "1" for True and "0" for False
794		-|0|(% style="width:486px" %)Boolean using "0" for True and "1" for False
795		-| |(% style="width:486px" %)
796		-|(% colspan="2" style="width:710px" %)Other qualifiers
797		-|*|(% style="width:486px" %)an arbitrary number of digits (of the preceding type)
798		-|+|(% style="width:486px" %)at least one digit (of the preceding type)
799		-|( )|(% style="width:486px" %)optional digits (specified within the brackets)
800		-|\|(% style="width:486px" %)prefix for the special characters that must appear in the mask
801		-|N|(% style="width:486px" %)fixed number of digits used in the preceding textual representation of the month or the day
	1003	+|(% colspan="2" %)VTL special characters for the formatting masks
	1004	+|(% colspan="2" %)
	1005	+|(% colspan="2" %)Number
	1006	+|D|one numeric digit (if the scientific notation is adopted, D is only for the mantissa)
	1007	+|E|one numeric digit (for the exponent of the scientific notation)
	1008	+|. (dot)|possible separator between the integer and the decimal parts.
	1009	+|, (comma)|possible separator between the integer and the decimal parts.
	1010	+| |
	1011	+|(% colspan="2" %)Time and duration
	1012	+|C|century
	1013	+|Y|year
	1014	+|S|semester
	1015	+|Q|quarter
	1016	+|M|month
	1017	+|W|week
	1018	+|D|day
	1019	+|h|hour digit (by default on 24 hours)
	1020	+|M|minute
	1021	+|S|second
	1022	+|D|decimal of second
	1023	+|P|period indicator (representation in one digit for the duration)
	1024	+|P|number of the periods specified in the period indicator
	1025	+|AM/PM|indicator of AM / PM (e.g. am/pm for "am" or "pm")
	1026	+|MONTH|uppercase textual representation of the month (e.g., JANUARY for January)
	1027	+|DAY|uppercase textual representation of the day (e.g., MONDAY for Monday)
	1028	+|Month|lowercase textual representation of the month (e.g., january)
	1029	+|Day|lowercase textual representation of the month (e.g., monday)
	1030	+|Month|First character uppercase, then lowercase textual representation of the month (e.g., January)
	1031	+|Day|First character uppercase, then lowercase textual representation of the day using (e.g. Monday)
	1032	+| |
	1033	+|(% colspan="2" %)String
	1034	+|X|any string character
	1035	+|Z|any string character from "A" to "z"
	1036	+|9|any string character from "0" to "9"
	1037	+| |
	1038	+|(% colspan="2" %)Boolean
	1039	+|B|Boolean using "true" for True and "false" for False
	1040	+|1|Boolean using "1" for True and "0" for False
	1041	+|0|Boolean using "0" for True and "1" for False
	1042	+| |
	1043	+|(% colspan="2" %)Other qualifiers
	1044	+|*|an arbitrary number of digits (of the preceding type)
	1045	+|+|at least one digit (of the preceding type)
	1046	+|( )|optional digits (specified within the brackets)
	1047	+|\|prefix for the special characters that must appear in the mask
	1048	+|N|fixed number of digits used in the preceding textual representation of the month or the day
	1049	+| |
802	802
803		-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}}.
	1051	+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" %)^^42^^>>path:#sdfootnote42sym||name="sdfootnote42anc"]](%%)^^.
804	804
805	805	=== 12.4.5 Null Values ===
806	806
...	...	@@ -818,8 +818,10 @@
818	818
819	819	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).
820	820
821		-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.
	1069	+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
822	822
	1071	+TransformationScheme.
	1072	+
823	823	In case a literal is operand of a VTL Cast operation, the format specified in the Cast overrides all the possible otherwise specified formats.
824	824
825	825	{{putFootnotes/}}

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