Changes for page 16 Annex 6: Worked Use Case

Last modified by Helena on 2025/09/10 11:19

From 1.2 to 2.1 From 10.1 to 10.2

From version 2.1

edited by Helena
on 2025/05/23 01:18

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To version 10.1

edited by Artur
on 2025/05/27 17:43

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  == 16.1 Scope ==
--The scope of this Chapter is to show the SDMX-ML interactions with the Registry, database, and metadata repository for the use case scenario outlined in Chapter 3. The scenario is repeated below.
++The scope of this Chapter is to show the [[SDMX-ML>>doc:sdmx:Glossary.SDMX-ML.WebHome]] interactions with the Registry, database, and [[metadata repository>>doc:sdmx:Glossary.Metadata repository.WebHome]] for the use case scenario outlined in Chapter 3. The scenario is repeated below.
--The SDMX-ML examples used are version 2.1.
++The [[SDMX-ML>>doc:sdmx:Glossary.SDMX-ML.WebHome]] examples used are (% style="color:#e74c3c" %)version(%%) 2.1.
  == 16.2 Scenario ==
--This scenario is the dissemination of data and related reference metadata using SDMX web services. It shows how the data, reference metadata, and structural metadata are used to build a web dissemination system.
++This scenario is the dissemination of data and related [[reference metadata>>doc:sdmx:Glossary.Reference metadata.WebHome]] using [[SDMX>>doc:sdmx:Glossary.Statistical data and metadata exchange.WebHome]] web services. It shows how the data, [[reference metadata>>doc:sdmx:Glossary.Reference metadata.WebHome]], and [[structural metadata>>doc:sdmx:Glossary.Structural metadata.WebHome]] are used to build a web dissemination system.
  [[image:image-20250318221512-1.jpeg||data-xwiki-image-style-alignment="center"]]
  (% style="text-align: center;" %)
--**{{id name="image_47"/}}Figure 47: Process flow of an SDMX Web Data Dissemination System**
++**{{id name="image_47"/}}Figure 47: Process flow of an [[SDMX>>doc:sdmx:Glossary.Statistical data and metadata exchange.WebHome]] Web Data Dissemination System**
  (% style="width:753.446px" %)
  |**Process**|(% style="width:670px" %)**Description**
--|1|(% style="width:670px" %)Retrieve the DSD from a structural metadata source (e.g. an SDMX Registry), and create database tables.
--|2|(% style="width:670px" %)Read an SDMX data set file and load the data into the database
--|3|(% style="width:670px" %)Data discovery system continually synchronises its metadata with the structural metadata source. A user makes a data selection from choices built from the information held in an SDMX Registry (structural metadata such as category scheme, dataflow, DSD, data provider, provision agreements and data registration)
--|3|(% style="width:670px" %)These choices are logical choices, built from the dimension selections.
--|5|(% style="width:670px" %)The logical choice is formatted as an SDMX data query. This is passed to the Data Base which responds with an SDMX data set.
--|6|(% style="width:670px" %)Reference metadata relevant to the data returned is retrieved from a metadata repository.
--|7|(% style="width:670px" %)The data and metadata are passed to a visualization tool to display the data in tables, charts, graphs, maps etc. Often a download is offered in various formats. The download options often include also the DSD or MSD.
++|1|(% style="width:670px" %)Retrieve the [[DSD>>doc:sdmx:Glossary.Data structure definition.WebHome]] from a [[structural metadata>>doc:sdmx:Glossary.Structural metadata.WebHome]] source (e.g. an [[SDMX Registry>>doc:sdmx:Glossary.SDMX Registry.WebHome]]), and create database tables.
++|2|(% style="width:670px" %)Read an [[SDMX>>doc:sdmx:Glossary.Statistical data and metadata exchange.WebHome]] [[data set>>doc:sdmx:Glossary.Data set.WebHome]] file and load the data into the database
++|3|(% style="width:670px" %)Data discovery system continually synchronises its metadata with the [[structural metadata>>doc:sdmx:Glossary.Structural metadata.WebHome]] source. A user makes a data selection from choices built from the information held in an [[SDMX Registry>>doc:sdmx:Glossary.SDMX Registry.WebHome]] ([[structural metadata>>doc:sdmx:Glossary.Structural metadata.WebHome]] such as [[category scheme>>doc:sdmx:Glossary.Category scheme.WebHome]], [[dataflow>>doc:sdmx:Glossary.Dataflow.WebHome]], [[DSD>>doc:sdmx:Glossary.Data structure definition.WebHome]], [[data provider>>doc:sdmx:Glossary.Data provider.WebHome]], [[provision agreements>>doc:sdmx:Glossary.Provision agreement.WebHome]] and data registration)
++|3|(% style="width:670px" %)These choices are logical choices, built from the [[dimension>>doc:sdmx:Glossary.Dimension.WebHome]] selections.
++|5|(% style="width:670px" %)The logical choice is formatted as an [[SDMX>>doc:sdmx:Glossary.Statistical data and metadata exchange.WebHome]] data query. This is passed to the Data Base which responds with an [[SDMX>>doc:sdmx:Glossary.Statistical data and metadata exchange.WebHome]] [[data set>>doc:sdmx:Glossary.Data set.WebHome]].
++|6|(% style="width:670px" %)[[Reference metadata>>doc:sdmx:Glossary.Reference metadata.WebHome]] relevant to the data returned is retrieved from a [[metadata repository>>doc:sdmx:Glossary.Metadata repository.WebHome]].
++|7|(% style="width:670px" %)The data and metadata are passed to a visualization tool to display the data in tables, charts, graphs, (% style="color:#e74c3c" %)maps(%%) etc. Often a download is offered in various formats. The download options often include also the [[DSD>>doc:sdmx:Glossary.Data structure definition.WebHome]] or MSD.
  == 16.3 Structural Metadata ==
  === 16.3.1 Schematic ===
--The following structural metadata and provisioning metadata is used in the scenario.
++The following [[structural metadata>>doc:sdmx:Glossary.Structural metadata.WebHome]] and provisioning metadata is used in the scenario.
  [[image:image-20250318221512-2.jpeg||data-xwiki-image-style-alignment="center"]]
@@ -40,7 +40,7 @@
  === 16.3.2 Data Structure Definition ===
--For the reasons of clarity a sub set of the contents of the Code Lists and Concept Schemes are used in this example, and only a few of the DSD Attributes are used.
++For the reasons of clarity a sub set of the contents of the [[Code Lists>>doc:sdmx:Glossary.Code list.WebHome]] and [[Concept Schemes>>doc:sdmx:Glossary.Concept scheme.WebHome]] are used in this example, and only a few of the [[DSD>>doc:sdmx:Glossary.Data structure definition.WebHome]] [[Attributes>>doc:sdmx:Glossary.Attribute.WebHome]] are used.
  (% class="wikigeneratedid" id="HDimensions" %)
  **Dimensions**
@@ -75,9 +75,11 @@
  (% style="text-align: center;" %)
  **{{id name="image_49"/}}Figure 49: User Case - Create Database Tables from DSD**
--The following SDMX-ML is extracted from the Registry using the REST query http:~/~/[ ws-entry-point]/DataStructure_ECB/ECB_EXR1
++The following [[SDMX-ML>>doc:sdmx:Glossary.SDMX-ML.WebHome]] is extracted from the Registry using the REST query
++http:~/~/[ ws-entry-point]/DataStructure_ECB/ECB_EXR1
--===== Dimensions =====
++(% class="wikigeneratedid" id="HDimensions" %)
++**Dimensions**
  [[image:image-20250318221512-8.jpeg||data-xwiki-image-style-alignment="center"]]
@@ -86,9 +86,9 @@
  (% class="wikigeneratedid" id="HNotes" %)
  **Notes**
--1. A Dimension can state its position in the key, but the actual sequence is defined by the sequence in the <DimensionList> i.e. the inferred sequence in the <DimensionList> takes precedence over the value of the position attribute.
--1. This DSD is converted from version 2.0. The version 2.0 Concepts were standalone in the form  <Concept agencyID=”ECB” version=”1.0”/>
--1. The standalone concept is not supported in 2.1 and any standalone concept is placed in a Concept Scheme with the Id “STANDALONE_CONCEPT_SCHEME” of the version corresponding to the version of the original standalone concept.
++1. A [[Dimension>>doc:sdmx:Glossary.Dimension.WebHome]] can state its position in the key, but the actual sequence is defined by the sequence in the i.e. the inferred sequence in the  takes precedence over the value of the position attribute.
++1. This [[DSD>>doc:sdmx:Glossary.Data structure definition.WebHome]] is converted from (% style="color:#e74c3c" %)version(%%) 2.0. The (% style="color:#e74c3c" %)version(%%) 2.0 (% style="color:#e74c3c" %)Concepts(%%) were standalone in the form  <Concept agencyID=”ECB” version=”1.0”/>
++1. The standalone (% style="color:#e74c3c" %)concept(%%) is not supported in 2.1 and any standalone (% style="color:#e74c3c" %)concept(%%) is placed in a [[Concept Scheme>>doc:sdmx:Glossary.Concept scheme.WebHome]] with the Id “STANDALONE_CONCEPT_SCHEME” of the (% style="color:#e74c3c" %)version(%%) corresponding to the (% style="color:#e74c3c" %)version(%%) of the original standalone (% style="color:#e74c3c" %)concept(%%).
  (% class="wikigeneratedid" id="HGroup-1" %)
  **Group**
@@ -98,24 +98,25 @@
  **Notes:**
--1. A Group in version 2.1 plays the same role as it does in version 2.0 except that it does not group Series in the data set. The Group in version 2.1 is used solely as a mechanism to attach Attributes in the data set.
--1. The Group in version 2.1 is retained for compatibility with version 2.0 and for avoiding repetition in the new Attribute Relationship construct which is introduced in version 2.1.
++1. A Group in (% style="color:#e74c3c" %)version(%%) 2.1 plays the same role as it does in (% style="color:#e74c3c" %)version(%%) 2.0 except that it does not group Series in the [[data set>>doc:sdmx:Glossary.Data set.WebHome]]. The Group in (% style="color:#e74c3c" %)version(%%) 2.1 is used solely as a mechanism to attach [[Attributes>>doc:sdmx:Glossary.Attribute.WebHome]] in the [[data set>>doc:sdmx:Glossary.Data set.WebHome]].
++1. The Group in (% style="color:#e74c3c" %)version(%%) 2.1 is retained for compatibility with (% style="color:#e74c3c" %)version(%%) 2.0 and for avoiding repetition in the new [[Attribute Relationship>>doc:sdmx:Glossary.Attribute relationship.WebHome]] construct which is introduced in (% style="color:#e74c3c" %)version(%%) 2.1.
--===== Attributes =====
++(% class="wikigeneratedid" id="HAttributes" %)
++**Attributes**
  [[image:image-20250318221512-10.jpeg||data-xwiki-image-style-alignment="center"]]
  [[image:image-20250318221512-11.jpeg||data-xwiki-image-style-alignment="center"]]
--Note that for brevity only the XML of the DECIMALS (relationship to a group) COLLECTION (relationship to a set of Dimensions) and OBS_CONF (relationship to the Primary Measure) are shown in full.
++Note that for brevity only the XML of the [[DECIMALS>>doc:sdmx:Glossary.Decimals.WebHome]] (relationship to a group) COLLECTION (relationship to a set of [[Dimensions>>doc:sdmx:Glossary.Dimension.WebHome]]) and OBS_CONF (relationship to the Primary [[Measure>>doc:sdmx:Glossary.Measure.WebHome]]) are shown in full.
  (% class="wikigeneratedid" id="HNotes-1" %)
  **Notes**
--1. The Attribute has a relationship to either a data set of one or more Dimensions as described in Chapter 4.
--1. DECIMALS has a relationship to a Group with the Id of Group.
--1. COLLECTION has a relationship to a set of Dimensions – in this case this is, in reality, the series key as this has been converted from version 2.0. It is possible for an attribute to have a relationship with just one, a few, or all of the Dimensions.
--1. OBS_CONF has a relationship with the Primary Measure.
++1. The [[Attribute>>doc:sdmx:Glossary.Attribute.WebHome]] has a relationship to either a [[data set>>doc:sdmx:Glossary.Data set.WebHome]] of one or more [[Dimensions>>doc:sdmx:Glossary.Dimension.WebHome]] as described in Chapter 4.
++1. [[DECIMALS>>doc:sdmx:Glossary.Decimals.WebHome]] has a relationship to a Group with the Id of Group.
++1. COLLECTION has a relationship to a set of [[Dimensions>>doc:sdmx:Glossary.Dimension.WebHome]] – in this case this is, in reality, the [[series key>>doc:sdmx:Glossary.Series key.WebHome]] as this has been converted from (% style="color:#e74c3c" %)version(%%) 2.0. It is possible for an [[attribute>>doc:sdmx:Glossary.Attribute.WebHome]] to have a relationship with just one, a few, or all of the [[Dimensions>>doc:sdmx:Glossary.Dimension.WebHome]].
++1. OBS_CONF has a relationship with the Primary [[Measure>>doc:sdmx:Glossary.Measure.WebHome]].
  (% class="wikigeneratedid" id="HMeasure" %)
  **Measure**
@@ -122,7 +122,7 @@
  [[image:image-20250318221512-12.jpeg||data-xwiki-image-style-alignment="center"]]
--A typical database schema that can be set up using this DSD is shown below.
++A typical database schema that can be set up using this [[DSD>>doc:sdmx:Glossary.Data structure definition.WebHome]] is shown below.
  (% class="wikigeneratedid" id="HSeriesKeyTable" %)
  **Series Key Table**
@@ -156,7 +156,7 @@
  (% style="text-align: center;" %)
  **{{id name="image_53"/}}Figure 53: Loading an SDMX Dataset into a Database **
--The following is an extract from the SDMX dataset.
++The following is an extract from the [[SDMX>>doc:sdmx:Glossary.Statistical data and metadata exchange.WebHome]] [[dataset>>doc:sdmx:Glossary.Data set.WebHome]].
  [[image:image-20250319123255-1.png||data-xwiki-image-style-alignment="center"]]
@@ -167,11 +167,11 @@
  (% class="wikigeneratedid" id="HNotes-2" %)
  **Notes**
--1. The reference to the DSD is given in the message header and given a local structureId
--1. The local structureId (DSD) is referenced from the DataSet
--1. A Group does not contain Series in version 2.1: it is used solely to declare attributes
--1. The first <Obs> in the first <Series> has an OBS_VALUE of “NaN”. This is an XML expression that declared a value of “not a number”, thus allowing a “missing value” to be declared.
--1. A dataset can contain observations from different frequencies.
++1. The reference to the [[DSD>>doc:sdmx:Glossary.Data structure definition.WebHome]] is given in the message header and given a local structureId
++1. The local structureId ([[DSD>>doc:sdmx:Glossary.Data structure definition.WebHome]]) is referenced from the [[DataSet>>doc:sdmx:Glossary.Data set.WebHome]]
++1. A Group does not contain Series in (% style="color:#e74c3c" %)version(%%) 2.1: it is used solely to declare attributes
++1. The first in the first has an OBS_VALUE of “NaN”. This is an XML expression that declared a value of “not a number”, thus allowing a “missing value” to be declared.
++1. A [[dataset>>doc:sdmx:Glossary.Data set.WebHome]] can contain observations from different frequencies.
  The diagrams below show the database content based on the schema created.
@@ -199,7 +199,7 @@
  [[image:image-20250318221512-19.jpeg||data-xwiki-image-style-alignment="center"]]
--The SDMX web service of the database can now be searched for in the Registry.
++The [[SDMX>>doc:sdmx:Glossary.Statistical data and metadata exchange.WebHome]] web service of the database can now be searched for in the Registry.
  === 16.4.4 Retrieve and Visualise Category Scheme and Dataflows ===
@@ -208,7 +208,7 @@
  (% style="text-align: center;" %)
  **{{id name="image_54"/}}Figure 54: Building a Search Screen from Structural Metadata**
--The following REST query will return the Category Scheme and Categorisations that reference any of the Categories in the scheme.
++The following REST query will return the [[Category Scheme>>doc:sdmx:Glossary.Category scheme.WebHome]] and Categorisations that reference any of the [[Categories>>doc:sdmx:Glossary.Category.WebHome]] in the scheme.
  [[http:~~/~~/ ~[ws-entry-point~]/categoryscheme/ECB/SDW_ECONOMIC_CONCEPTS/1.0?references=parents>>http:// [ws-entry-point]/categoryscheme/ECB/SDW_ECONOMIC_CONCEPTS/1.0?references=parents||rel="noopener noreferrer" target="_blank"]]
@@ -216,11 +216,11 @@
  [[image:image-20250318221512-22.jpeg||data-xwiki-image-style-alignment="center"]]
--The application will now retrieve the Dataflows in the list of Categorisations – in this case there is only one – effective exchange rates.
++The application will now retrieve the [[Dataflows>>doc:sdmx:Glossary.Dataflow.WebHome]] in the list of Categorisations – in this case there is only one – effective exchange rates.
--The following REST query will return the dataflow.
++The following REST query will return the [[dataflow>>doc:sdmx:Glossary.Dataflow.WebHome]].
--[[http:~~/~~/ ~[ws-entry-point~]/dataflow/ECB/2034482/1.0>>http:// [ws-entry-point]/dataflow/ECB/2034482/1.0||rel="noopener noreferrer" target="_blank"]]
++[[http:~~/~~/ ~[ws-entry-point~]/dataflow/ECB/2034482/1.0>>http://[ws-entry-point]/dataflow/ECB/2034482/1.0||rel="noopener noreferrer" target="_blank"]]
  [[image:image-20250318221512-23.jpeg||data-xwiki-image-style-alignment="center"]]
@@ -228,9 +228,9 @@
 . Query application queries the Registry for the Provision Agreement.
 . Query application queries the Registry for data Registrations.
--1. If there is a data source registered then the dataflow is displayed and can be selected.
++1. If there is a [[data source>>doc:sdmx:Glossary.Data source.WebHome]] registered then the [[dataflow>>doc:sdmx:Glossary.Dataflow.WebHome]] is displayed and can be selected.
--The following REST query will return any provision agreements referenced from the dataflow
++The following REST query will return any [[provision agreements>>doc:sdmx:Glossary.Provision agreement.WebHome]] referenced from the [[dataflow>>doc:sdmx:Glossary.Dataflow.WebHome]]
  [[http:~~/~~/~[ws-entry-point~]/dataflow/ECB/2034482/1.0?references=provisionagreement>>http://[ws-entry-point]/dataflow/ECB/2034482/1.0?references=provisionagreement||rel="noopener noreferrer" target="_blank"]]
@@ -239,22 +239,24 @@
  (% class="wikigeneratedid" id="HNotes-3" %)
  **Notes**
--~1. The <URN> contains the same identification information as the individual attributes in the <Ref> tag in the context of the <Dataflow> and <Structure> tags (the <Dataflow> identifies that the <Structure> is a DataStructure).
++~1. The contains the same identification information as the individual [[attributes>>doc:sdmx:Glossary.Attribute.WebHome]] in the tag in the context of the <Dataflow> and tags (the <Dataflow> identifies that the is a DataStructure).
--The following REST query will return the Data Provider Scheme that contains the Data Provider connected to the Provision Agreement. Note that this is not necessary in order to query for the data unless the Data Provider contains information required by the query application (such as the name of the Data Provider).
++The following REST query will return the [[Data Provider Scheme>>doc:sdmx:Glossary.Data provider scheme.WebHome]] that contains the [[Data Provider>>doc:sdmx:Glossary.Data provider.WebHome]] connected to the [[Provision Agreement>>doc:sdmx:Glossary.Provision agreement.WebHome]]. Note that this is not necessary in order to query for the data unless the [[Data Provider>>doc:sdmx:Glossary.Data provider.WebHome]] contains information required by the query application (such as the name of the [[Data Provider>>doc:sdmx:Glossary.Data provider.WebHome]]).
--[[http:~~/~~/~[ws-entry-point~]/dataprovider/ECB>>http://[ws-entry-point]/dataprovider/ECB||rel="noopener noreferrer" target="_blank"]]
++[[http:~~/~~/~[ws-entry-point~]/dataprovider/ECB>>http:// [ws-entry-point]/dataprovider/ECB||rel="noopener noreferrer" target="_blank"]]
  (% class="wikigeneratedid" id="HNotes-4" %)
  **Notes**
--~1. As an Agency can have only one Data Provider Scheme and this has a mandatory Id of DATA_PROVIDER_SCHEME and must be version 1.0 there is no need to specify any other parameters to the REST query.
++1.
--This returns the following as part of the Data Provider Scheme.
++As an Agency can have only one [[Data Provider Scheme>>doc:sdmx:Glossary.Data provider scheme.WebHome]] and this has a mandatory Id of DATA_PROVIDER_SCHEME and must be (% style="color:#e74c3c" %)version(%%) 1.0 there is no need to specify any other parameters to the REST query.
++This returns the following as part of the [[Data Provider Scheme>>doc:sdmx:Glossary.Data provider scheme.WebHome]].
++
  [[image:image-20250318221512-25.jpeg||data-xwiki-image-style-alignment="center"]]
--The following Registry query will return the REST data source referenced in a Registration for the Provision Agreement
++The following Registry query will return the REST [[data source>>doc:sdmx:Glossary.Data source.WebHome]] referenced in a Registration for the Provision Agreement
  [[image:image-20250318221512-26.jpeg||data-xwiki-image-style-alignment="center"]]
@@ -266,7 +266,7 @@
  [[http:~~/~~/~[ws-entry-point~] /~[RESTParameters~]>>http://[ws-entry-point] /[RESTParameters||rel="noopener noreferrer" target="_blank"]]]
--Where [ws-entry-point] is the URL of the SDMX web service and [RESTParameters] are the query parameters.
++Where [ws-entry-point] is the URL of the [[SDMX>>doc:sdmx:Glossary.Statistical data and metadata exchange.WebHome]] web service and [RESTParameters] are the query parameters.
  The application can now visualize the information it has retrieved from the Registry in a way that is meaningful to the user. An example visualization is shown below.
@@ -275,13 +275,13 @@
  (% style="text-align: center;" %)
  **{{id name="image_55"/}}Figure 55: Example Query Screen Built from SDMX Category Scheme and Dataflows**
--The user will select the Category and this then shows the Dataflows that are available and which have data available for query (i.e. there is a Registration). There can be many such Dataflows but in this example there is only one.
++The user will select the [[Category>>doc:sdmx:Glossary.Category.WebHome]] and this then shows the [[Dataflows>>doc:sdmx:Glossary.Dataflow.WebHome]] that are available and which have data available for query (i.e. there is a Registration). There can be many such [[Dataflows>>doc:sdmx:Glossary.Dataflow.WebHome]] but in this example there is only one.
  === 16.4.5 Build Dimension Selection and Logical Query ===
  [[image:image-20250318221512-29.jpeg||data-xwiki-image-style-alignment="center"]]
--Clicking on the Dataflow will cause the query application to query the Registry for the DSD associated to the Dataflow. The Dimensions and the relevant codes associated with the Dimensions are then shown for detailed data selections.
++Clicking on the [[Dataflow>>doc:sdmx:Glossary.Dataflow.WebHome]] will cause the query application to query the Registry for the [[DSD>>doc:sdmx:Glossary.Data structure definition.WebHome]] associated to the [[Dataflow>>doc:sdmx:Glossary.Dataflow.WebHome]]. The [[Dimensions>>doc:sdmx:Glossary.Dimension.WebHome]] and the relevant [[codes>>doc:sdmx:Glossary.Code.WebHome]] associated with the [[Dimensions>>doc:sdmx:Glossary.Dimension.WebHome]] are then shown for detailed data selections.
  [[image:image-20250318221512-30.jpeg||data-xwiki-image-style-alignment="center"]]
@@ -288,13 +288,13 @@
  (% style="text-align: center;" %)
  **{{id name="image_56"/}}Figure 56: Selection Screen build from SDMX DSD**
--The user can click on each of the Dimensions and the relevant code selections are displayed. Note that in the example above the application is assumed to have queries for all the keys so that it can process them in order to grey-out the Dimension selections for which there is no data. These are greyed-out based on the current selections in the other Dimensions. This shows the importance of content constraints in a web dissemination system, as they can be used to guide the user to make only the selections that will return data. The same result can be achieved if these constraints are available for query (e.g. in a Registry), but this is a less effective way of processing if the contenrts of the database are dynamic.
++The user can click on each of the [[Dimensions>>doc:sdmx:Glossary.Dimension.WebHome]] and the relevant [[code>>doc:sdmx:Glossary.Code.WebHome]] selections are displayed. Note that in the example above the application is assumed to have queries for all the keys so that it can process them in order to grey-out the [[Dimension>>doc:sdmx:Glossary.Dimension.WebHome]] selections for which there is no data. These are greyed-out based on the current selections in the other [[Dimensions>>doc:sdmx:Glossary.Dimension.WebHome]]. This shows the importance of content (% style="color:#e74c3c" %)constraints(%%) in a web dissemination system, as they can be used to guide the user to make only the selections that will return data. The same result can be achieved if these (% style="color:#e74c3c" %)constraints(%%) are available for query (e.g. in a Registry), but this is a less effective way of processing if the contenrts of the database are dynamic.
  === 16.4.6 Query Database ===
  [[image:image-20250318221512-31.jpeg||data-xwiki-image-style-alignment="center"]]
--The logical query of the user is converted to an SDMX query and sent to the Data Web Service of the data publisher. The Data Web Service may also query the Metadata Repository in order to return both data and related metadata to the user application. The Data Web Service may also require structural metadata (DSD and MSD and related Code Lists and Concepts) from the structural metadata repository, in this example this an SDMX Registry.
++The logical query of the user is converted to an [[SDMX>>doc:sdmx:Glossary.Statistical data and metadata exchange.WebHome]] query and sent to the Data Web Service of the data publisher. The Data Web Service may also query the [[Metadata Repository>>doc:sdmx:Glossary.Metadata repository.WebHome]] in order to return both data and related metadata to the user application. The Data Web Service may also require [[structural metadata>>doc:sdmx:Glossary.Structural metadata.WebHome]] ([[DSD>>doc:sdmx:Glossary.Data structure definition.WebHome]] and [[MSD>>doc:sdmx:Glossary.Metadata structure definition.WebHome]] and related [[Code Lists>>doc:sdmx:Glossary.Code list.WebHome]] and (% style="color:#e74c3c" %)Concepts(%%)) from the [[structural metadata>>doc:sdmx:Glossary.Structural metadata.WebHome]] repository, in this example this an [[SDMX Registry>>doc:sdmx:Glossary.SDMX Registry.WebHome]].
  (% class="wikigeneratedid" id="HDataQueryLogicalSelections" %)
  **Data Query Logical Selections**
@@ -317,7 +317,7 @@
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--The returned data and metadata can be presented to the user in many ways – tables, graphs, charts, maps etc. SDMX does not support visualization directly but it is possible to define roles for a Dimension and Attribute in the DSD. For instance, it is possible to assign a role of “Geography” or “Title” or “Measure Unit” etc. which will aid a data visualization service to present this information in a meaningful way to the user.
++The returned data and metadata can be presented to the user in many ways – tables, graphs, charts, (% style="color:#e74c3c" %)maps(%%) etc. [[SDMX>>doc:sdmx:Glossary.Statistical data and metadata exchange.WebHome]] does not support visualization directly but it is possible to define roles for a [[Dimension>>doc:sdmx:Glossary.Dimension.WebHome]] and [[Attribute>>doc:sdmx:Glossary.Attribute.WebHome]] in the [[DSD>>doc:sdmx:Glossary.Data structure definition.WebHome]]. For instance, it is possible to assign a role of “Geography” or “[[Title>>doc:sdmx:Glossary.Title.WebHome]]” or “[[Measure>>doc:sdmx:Glossary.Measure.WebHome]] Unit” etc. which will aid a data visualization service to present this information in a meaningful way to the user.
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