Skip to Content
Last modified by Helena K. on 2026/06/08 17:06
From version 21.3
edited by Helena K.
on 2026/06/08 17:01
Change comment: There is no comment for this version
To version 21.5
edited by Helena K.
on 2026/06/08 17:03
Change comment: There is no comment for this version

Summary

Details

Page properties
Content
... ... @@ -4,28 +4,28 @@
4 4  
5 5  == 7.1 Context ==
6 6  
7 -Besides the possibility to extend the components of Data Structure Definitions by metadata attributes defined in Metadata Structure Definitions, the SDMX metamodel allows metadata to describe any identifiable artefact. These metadata can be:
7 +Besides the possibility to extend the [[components>>doc:sdmx:Glossary 2\.1.Component.WebHome]] of [[Data Structure Definitions>>doc:sdmx:Glossary 2\.1.Data structure definition.WebHome]] by metadata [[attributes>>doc:sdmx:Glossary 2\.1.Attribute.WebHome]] defined in [[Metadata Structure Definitions>>doc:sdmx:Glossary 2\.1.Metadata structure definition.WebHome]], the [[SDMX>>doc:sdmx:Glossary 2\.1.Statistical data and metadata exchange.WebHome]] metamodel allows metadata to describe any [[identifiable artefact>>doc:sdmx:Glossary 2\.1.Identifiable artefact.WebHome]]. These metadata can be:
8 8  
9 9  1. Exchanged without the need to embed it within the object that it is describing.
10 -1. Stored separately from the object that it describes, yet be linked to it (for example, an organisation has a metadata repository which supports the dissemination of metadata resulting from metadata requests generated by systems or services that have access to the object for which the metadata pertains. This is common in web dissemination where additional metadata is available for viewing (and eventually downloading) by clicking on an “information” icon next to the object to which the metadata is attached).
11 -1. Versioned and maintained like structural metadata, but from Metadata Providers than Agencies.
10 +1. Stored separately from the object that it describes, yet be linked to it (for example, an organisation has a [[metadata repository>>doc:sdmx:Glossary 2\.1.Metadata repository.WebHome]] which supports the dissemination of metadata resulting from metadata requests generated by systems or services that have access to the object for which the metadata pertains. This is common in web dissemination where additional metadata is available for viewing (and eventually downloading) by clicking on an “information” icon next to the object to which the metadata is attached).
11 +1. Versioned and maintained like [[structural metadata>>doc:sdmx:Glossary 2\.1.Structural metadata.WebHome]], but from Metadata Providers than Agencies.
12 12  1. Reported according to a defined structure.
13 13  
14 14  In order to achieve this, the following structures are modelled:
15 15  
16 -* The Metadata Structure Definition which comprises the metadata attributes that can be attached to the various object types (these attributes can be structured in a hierarchy), together with any constraints that may apply (e.g., association to a code list that contains valid values for the attribute when reported in a metadata set),
17 -* The Metadataflow and/or Metadata Provision Agreement, which contains the objects to which the metadata are to be associated (attached),
18 -* The Metadata Set, which contains reported metadata.
16 +* The [[Metadata Structure Definition>>doc:sdmx:Glossary 2\.1.Metadata structure definition.WebHome]] which comprises the metadata [[attributes>>doc:sdmx:Glossary 2\.1.Attribute.WebHome]] that can be attached to the various object types (these [[attributes>>doc:sdmx:Glossary 2\.1.Attribute.WebHome]] can be structured in a [[hierarchy>>doc:sdmx:Glossary 2\.1.Hierarchy.WebHome]]), together with any [[constraints>>doc:sdmx:Glossary 2\.1.Constraint.WebHome]] that may apply (e.g., association to a [[code list>>doc:sdmx:Glossary 2\.1.Code list.WebHome]] that contains valid values for the [[attribute>>doc:sdmx:Glossary 2\.1.Attribute.WebHome]] when reported in a [[metadata set>>doc:sdmx:Glossary 2\.1.Metadata set.WebHome]]),
17 +* The [[Metadataflow>>doc:sdmx:Glossary 2\.1.Metadataflow.WebHome]] and/or Metadata [[Provision Agreement>>doc:sdmx:Glossary 2\.1.Provision agreement.WebHome]], which contains the objects to which the metadata are to be associated (attached),
18 +* The [[Metadata Set>>doc:sdmx:Glossary 2\.1.Metadata set.WebHome]], which contains reported metadata.
19 19  
20 20  == 7.2 Inheritance ==
21 21  
22 22  === 7.2.1 Introduction ===
23 23  
24 -As with the Data Structure Definition Structure, many of the constructs in this layer of the model inherit from the SDMX Base layer. Therefore, it is necessary to study both the inheritance and the relationship diagrams to understand the functionality of individual
24 +As with the [[Data Structure Definition>>doc:sdmx:Glossary 2\.1.Data structure definition.WebHome]] Structure, many of the constructs in this layer of the model inherit from the [[SDMX>>doc:sdmx:Glossary 2\.1.Statistical data and metadata exchange.WebHome]] Base layer. Therefore, it is necessary to study both the inheritance and the relationship diagrams to understand the functionality of individual
25 25  
26 -packages. The diagram below shows the full inheritance tree for the classes concerned with the MetadataStructureDefinition, the MetadataProvisionAgreement, the Metadataflow and the MetadataSet.
26 +packages. The diagram below shows the full inheritance tree for the classes concerned with the MetadataStructureDefinition, the MetadataProvisionAgreement, the [[Metadataflow>>doc:sdmx:Glossary 2\.1.Metadataflow.WebHome]] and the MetadataSet.
27 27  
28 -There are very few additional classes in the MetadataStructureDefinition package that do not themselves inherit from classes in the SDMX Base. In other words, the SDMX Base gives most of the structure of this sub model both in terms of associations and in terms of attributes. The relationship diagrams shown in this section show clearly when these associations are inherited from the SDMX Base (see the Appendix “A Short Guide to UML in the SDMX Information Model” to see the diagrammatic notation used to depict this).
28 +There are very few additional classes in the MetadataStructureDefinition package that do not themselves inherit from classes in the [[SDMX>>doc:sdmx:Glossary 2\.1.Statistical data and metadata exchange.WebHome]] Base. In other words, the [[SDMX>>doc:sdmx:Glossary 2\.1.Statistical data and metadata exchange.WebHome]] Base gives most of the structure of this sub model both in terms of associations and in terms of [[attributes>>doc:sdmx:Glossary 2\.1.Attribute.WebHome]]. The relationship diagrams shown in this section show clearly when these associations are inherited from the [[SDMX>>doc:sdmx:Glossary 2\.1.Statistical data and metadata exchange.WebHome]] Base (see the Appendix “A Short Guide to UML in the [[SDMX Information Model>>doc:sdmx:Glossary 2\.1.SDMX Information Model.WebHome]]” to see the diagrammatic notation used to depict this).
29 29  
30 30  === 7.2.2 Class Diagram - Inheritance ===
31 31  
... ... @@ -39,15 +39,15 @@
39 39  
40 40  It is important to the understanding of the relationship class diagrams presented in this section to identify the concrete classes that inherit from the abstract classes.
41 41  
42 -The concrete classes in this part of the SDMX metamodel, which require to be maintained by Maintenance Agencies, all inherit from MaintainableArtefact. These are:
42 +The concrete classes in this part of the [[SDMX>>doc:sdmx:Glossary 2\.1.Statistical data and metadata exchange.WebHome]] metamodel, which require to be maintained by [[Maintenance Agencies>>doc:sdmx:Glossary 2\.1.Maintenance agency.WebHome]], all inherit from MaintainableArtefact. These are:
43 43  
44 -//StructureUsage// (concrete class is Metadataflow)
44 +//StructureUsage// (concrete class is [[Metadataflow>>doc:sdmx:Glossary 2\.1.Metadataflow.WebHome]])
45 45  //Structure// (concrete class is MetadataStructureDefinition)
46 46  MetadataProvisionAgreement
47 47  
48 -These classes also inherit the identity and versioning facets of //IdentifiableArtefact//, //NameableArtefact// and //VersionableArtefact//.
48 +These classes also inherit the identity and versioning [[facets>>doc:sdmx:Glossary 2\.1.Facet.WebHome]] of //IdentifiableArtefact//, //NameableArtefact// and //VersionableArtefact//.
49 49  
50 -A //Structure// may contain several lists of components. In this case the MetadataStructureDefinition acts as a list and contains //Component//s, i.e., MetadataAttributes.
50 +A //Structure// may contain several lists of [[components>>doc:sdmx:Glossary 2\.1.Component.WebHome]]. In this case the MetadataStructureDefinition acts as a list and contains //Component//s, i.e., MetadataAttributes.
51 51  
52 52  == 7.3 Metadata Structure Definition ==
53 53  
... ... @@ -57,7 +57,7 @@
57 57  
58 58  === 7.3.2 Structures Already Described ===
59 59  
60 -The MetadataStructureDefinition only contains MetadataAttributes, since target objects are contained in Metadataflow and MetadataProvisionAgreement, since SDMX 3.0.
60 +The MetadataStructureDefinition only contains MetadataAttributes, since target objects are contained in [[Metadataflow>>doc:sdmx:Glossary 2\.1.Metadataflow.WebHome]] and MetadataProvisionAgreement, since [[SDMX>>doc:sdmx:Glossary 2\.1.Statistical data and metadata exchange.WebHome]] 3.0.
61 61  
62 62  === 7.3.3 Class Diagram – Relationship ===
63 63  
... ... @@ -69,23 +69,23 @@
69 69  
70 70  ==== 7.3.4.1 Narrative ====
71 71  
72 -In brief, a MetadataStructureDefinition (MSD) defines the MetadataAttributes, within an MetadataAttributeDescriptor, that can be associated with the objects identified in the Metadataflows and MetadataProvisionAgreements that refer to the MSD. The hierarchy of the MetadataAttributes is specified within the MetadataAttributeDescriptor.
72 +In brief, a MetadataStructureDefinition ([[MSD>>doc:sdmx:Glossary 2\.1.Metadata structure definition.WebHome]]) defines the MetadataAttributes, within an MetadataAttributeDescriptor, that can be associated with the objects identified in the [[Metadataflows>>doc:sdmx:Glossary 2\.1.Metadataflow.WebHome]] and MetadataProvisionAgreements that refer to the [[MSD>>doc:sdmx:Glossary 2\.1.Metadata structure definition.WebHome]]. The [[hierarchy>>doc:sdmx:Glossary 2\.1.Hierarchy.WebHome]] of the MetadataAttributes is specified within the MetadataAttributeDescriptor.
73 73  
74 -The MetadataAttributeDescriptor comprises a set of MetadataAttributes – these can be defined as a hierarchy. Each MetadataAttribute identifies a Concept that is reported or disseminated in a MetadataSet (/conceptIdentity) that uses this MetadataStructureDefinition. Different MetadataAttributes in the same MetadataAttributeDescriptor can use Concepts from different ConceptSchemes. Note that a MetadataAttribute does not link to a Concept that defines its role in this MetadataStructureDefinition (i.e., the MetadataAttribute does not play a role).
74 +The MetadataAttributeDescriptor comprises a set of MetadataAttributes – these can be defined as a [[hierarchy>>doc:sdmx:Glossary 2\.1.Hierarchy.WebHome]]. Each MetadataAttribute identifies a [[Concept>>doc:sdmx:Glossary 2\.1.Concept.WebHome]] that is reported or disseminated in a MetadataSet (/conceptIdentity) that uses this MetadataStructureDefinition. Different MetadataAttributes in the same MetadataAttributeDescriptor can use [[Concepts>>doc:sdmx:Glossary 2\.1.Concept.WebHome]] from different ConceptSchemes. Note that a MetadataAttribute does not link to a [[Concept>>doc:sdmx:Glossary 2\.1.Concept.WebHome]] that defines its role in this MetadataStructureDefinition (i.e., the MetadataAttribute does not play a role).
75 75  
76 -The MetadataAttribute can be specified as having multiple occurrences and/or specified as being mandatory (minOccurs=1 or more) or optional (minOccurs=0). A hierarchical MetadataStructureDefinition can be defined by specifying a hierarchy for a MetadataAttribute.
76 +The MetadataAttribute can be specified as having multiple occurrences and/or specified as being mandatory (minOccurs=1 or more) or optional (minOccurs=0). A hierarchical MetadataStructureDefinition can be defined by specifying a [[hierarchy>>doc:sdmx:Glossary 2\.1.Hierarchy.WebHome]] for a MetadataAttribute.
77 77  
78 -It can be seen from this, that the specification of the objects to which a MetadataAttribute can be attached is indirect: the MetadataAttributes are defined in a MetadataStructureDefinition, but they are attached to one or more IdentifiableArtefacts as defined in the Metadataflows or
78 +It can be seen from this, that the specification of the objects to which a MetadataAttribute can be attached is indirect: the MetadataAttributes are defined in a MetadataStructureDefinition, but they are attached to one or more IdentifiableArtefacts as defined in the [[Metadataflows>>doc:sdmx:Glossary 2\.1.Metadataflow.WebHome]] or
79 79  
80 80  MetadataProvisionAgreements. This gives a flexible mechanism by which the actual objects need not be defined in concrete terms in the model but are defined dynamically by the IdentifiableObjectSelection. In this way, the MetadataStructureDefinition can be used to define any set of MetadataAttributes regardless of the objects to which they can be attached.
81 81  
82 -Each MetadataAttribute can have a Representation specified (using the /localRepresentation association). If this is not specified in the MetadataStructureDefinition then the Representation is taken from that defined for the Concept (the coreRepresentation association).
82 +Each MetadataAttribute can have a [[Representation>>doc:sdmx:Glossary 2\.1.Representation.WebHome]] specified (using the /localRepresentation association). If this is not specified in the MetadataStructureDefinition then the [[Representation>>doc:sdmx:Glossary 2\.1.Representation.WebHome]] is taken from that defined for the (% style="color:#e74c3c" %)Concept(%%) (the coreRepresentation association).
83 83  
84 -The definition of the various types of Representation can be found in the specification of the Base constructs. Note that if the Representation is non-enumerated then the association is to the ExtendedFacet (which allows for XHTML as a FacetValueType). If the Representation is enumerated, then is must use a Codelist.
84 +The definition of the various types of [[Representation>>doc:sdmx:Glossary 2\.1.Representation.WebHome]] can be found in the specification of the Base constructs. Note that if the [[Representation>>doc:sdmx:Glossary 2\.1.Representation.WebHome]] is non-enumerated then the association is to the ExtendedFacet (which allows for XHTML as a FacetValueType). If the [[Representation>>doc:sdmx:Glossary 2\.1.Representation.WebHome]] is enumerated, then is must use a [[Codelist>>doc:sdmx:Glossary 2\.1.Code list.WebHome]].
85 85  
86 -The Metadataflow is linked to a MetadataStructureDefinition. The Metadataflow, in addition to the attributes inherited from the Base classes, it also has a list of IdentifiableObjectSelection constructs, which resolve into the IdentifiableArtefacts that the Metadatasets will refer to. The IdentifiableObjectSelection acts like a reference, but it may also include wildcarding part of the reference terms.
86 +The [[Metadataflow>>doc:sdmx:Glossary 2\.1.Metadataflow.WebHome]] is linked to a MetadataStructureDefinition. The [[Metadataflow>>doc:sdmx:Glossary 2\.1.Metadataflow.WebHome]], in addition to the [[attributes>>doc:sdmx:Glossary 2\.1.Attribute.WebHome]] inherited from the Base classes, it also has a list of IdentifiableObjectSelection constructs, which resolve into the IdentifiableArtefacts that the Metadatasets will refer to. The IdentifiableObjectSelection acts like a reference, but it may also include wildcarding part of the reference terms.
87 87  
88 -The MetadataProvisionAgreement is linked to a Metadataflow. The former, like the Metadataflow, may have IdentifiableObjectSelection constructs to be used for specifying the proper targets for reference metadata.
88 +The MetadataProvisionAgreement is linked to a [[Metadataflow>>doc:sdmx:Glossary 2\.1.Metadataflow.WebHome]]. The former, like the [[Metadataflow>>doc:sdmx:Glossary 2\.1.Metadataflow.WebHome]], may have IdentifiableObjectSelection constructs to be used for specifying the proper targets for [[reference metadata>>doc:sdmx:Glossary 2\.1.Reference metadata.WebHome]].
89 89  
90 90  ==== 7.3.4.2 Definitions ====
91 91  
© Semantic R&D Group, 2026