4 Specific Item Schemes

4.1 Introduction

The structures that are an arrangement of objects into hierarchies or lists based on characteristics, and which are maintained as a group inherit from ItemScheme. These concrete classes are:

Codelist
ConceptScheme
CategoryScheme
AgencyScheme, DataProviderScheme, MetadataProviderScheme,
DataConsumerScheme, OrganisationUnitScheme, which all inherit from the abstract class OrganisationScheme
ReportingTaxonomy
TransformationScheme
RulesetScheme
UserDefinedOperatorScheme
NamePersonalisationScheme
CustomTypeScheme
VtlMappingScheme

Note that the VTL related schemes (the last 6 of the above list) are detailed in a dedicated section below (section 15).

4.2 Inheritance View

The inheritance and relationship views are shown together in each of the diagrams in the specific sections below.

4.3 Codelist

4.3.1 Class Diagram

Figure 16: Class diagram of the Codelist

4.3.2 Explanation of the Diagram

4.3.2.1 Narrative

The Codelist inherits from the ItemScheme and therefore has the following attributes: id uri urn version validFrom validTo isExternalReference serviceURL structureURL isPartial

The Code inherits from Item and has the following attributes:

id
uri
urn

Both Codelist and Code have the association to InternationalString to support a multilingual name, an optional multi-lingual description, and an association to Annotation to support notes (not shown).

Through the inheritance the Codelist comprise one or more Codes, and the Code itself can have one or more child Codes in the (inherited) hierarchy association. Note that a child Code can have only one parent Code in this association. A more complex Hierarhcy, which allows multiple parents is described later.

A partial Codelist (where isPartial is set to 'true') is identical to a Codelist and contains the Code and associated names and descriptions, just as in a normal Codelist. However, its content is a subset of the full Codelist. The way this works is described in section 3.5.3.1 on ItemScheme.

4.3.2.2 Definitions

4.3.3 Class Diagram – Codelist Extension

Figure 17: Class diagram for Codelist Extension

4.3.3.1 Narrative

A Codelist may extend other Codelists via the CodelistExtension class. The latter, via the sequence, indicates the order of precedence of the extended Codelists for conflict resolution of Codes. Besides that, the prefix property is used to ensure uniqueness of inherited Codes in the extending^[1] Codelist in case conflicting Codes must be included in the latter. Each CodelistExtension association may include one InclusiveCodeSelection or one ExclusiveCodeSelection; those allow including or excluding a specific selection of Codes from the extended Codelists.

The code selection classes may have MemberValues in order to specify the subset of the Codes that should be included or excluded from the extended Codelist. A MemberValue may have a value that corresponds to a Code, including its children Codes (via the cascadeValues property), or even include instances of the wildcard character ‘%’ in order to point to a set of Codes with common parts in their identifiers.

4.3.3.2 Definitions

4.3.4 Class Diagram – Geospatial Codelist

The geospatial support is implemented via an extension of the normal Codelist. This is illustrated in the following diagrams.

Figure 18: Inheritance for the GeoCodelist

Figure 19: Class diagram for Geospatial Codelist

4.3.4.1 Narrative

A GeoCodelist is a specialisation of Codelist that includes geospatial information, by comprising a set of special Codes, i.e., GeoRefCodes. A GeoCodelist may be implemented by any of the two following classes, via the geoType property:

GeographicCodelist

GeoGridCodelist

The former, i.e., GeographicCodelist, comprises a set of GeoFeatureSetCodes, by adding a value in the Code that follows a pattern to represent a geo feature set.

The latter, i.e., GeoGridCodelist, comprises a set of GridCodes, which are related to the gridDefinition specified in the GeoGridCodelist.

4.3.4.2 Definitions

4.4 ValueList

4.4.1 Class Diagram

Figure 20: Class diagram of the ValueList

4.4.2 Explanation of the Diagram

4.4.2.1 Narrative

A ValueList inherits from EnumeratedList (and hence the MaintenableArtefact) and thus has the following attributes:

id
uri
urn
version
validFrom
validTo
isExternalReference
registryURL
structureURL
repositoryURL

ValueItem inherits from EnumeratedItem, which adds an id, with relaxed constraints, to the former.

Through the inheritance from NameableArtefact the ValueList has the association to InternationalString to support a multi-lingual name, an optional multi-lingual description, and an association to Annotation to support notes (not shown). Similarly, the ValueItem, inherits the association to InternationalString and to the Annotation from the EnumeratedItem.

The ValueList can have one or more ValueItems.

4.4.2.2 Definitions

4.5 Concept Scheme and Concepts

4.5.1 Class Diagram - Inheritance

Figure 21 Class diagram of the Concept Scheme

4.5.2 Explanation of the Diagram

The ConceptScheme inherits from the ItemScheme and therefore has the following attributes:

id
uri
urn
version validFrom validTo
isExternalReference
registryURL
structureURL
repositoryURL
isPartial

Concept inherits from Item and has the following attributes:

id
uri
urn

Through the inheritance from NameableArtefact both ConceptScheme and Concept have the association to InternationalString to support a multi-lingual name, an optional multilingual description, and an association to Annotation to support notes (not shown).

Through the inheritance from ItemScheme the ConceptScheme comprise one or more Concepts, and the Concept itself can have one or more child Concepts in the (inherited) hierarchy association. Note that a child Concept can have only one parent Concept in this association.

A partial ConceptScheme (where isPartial is set to “true”) is identical to a ConceptScheme and contains the Concept and associated names and descriptions, just as in a normal ConceptScheme. However, its content is a subset of the full ConceptScheme. The way this works is described in section 3.5.3.1 on ItemScheme.

4.5.3 Class Diagram Relationship

Figure 22: Relationship class diagram of the Concept Scheme

4.5.4 Explanation of the diagram

4.5.4.1 Narrative

The ConceptScheme can have one or more Concepts. A Concept can have zero or more child Concepts, thus supporting a hierarchy of Concepts. Note that a child Concept can have only one parent Concept in this association. The purpose of the hierarchy is to relate concepts that have a semantic relationship: for example, a Reporting_Country and Vis_a_Vis_Country may both have Country as a parent concept, or a CONTACT may have a PRIMARY_CONTACT as a child concept. It is not the purpose of such schemes to define reporting structures: these reporting structures are defined in the MetadataStructureDefinition.

The Concept can be associated with a coreRepresentation. The coreRepresentation is the specification of the format and value domain of the Concept when used on a structure like a DataStructureDefinition or a MetadataStructureDefinition, unless the specification of the Representation is overridden in the relevant structure definition. In a hierarchical ConceptScheme the Representation is inherited from the parent Concept unless overridden at the level of the child Concept.

The Representation is documented in more detail in the section on the SDMX Base.

The Concept may be related to a concept described in terms of the ISO/IEC 11179 standard. The ISOConceptReference identifies this concept and concept scheme in which it is contained.

4.5.4.2 Definitions

4.6 Category Scheme

4.6.1 Context

This package defines the structure that supports the definition of and relationships between categories in a category scheme. It is similar to the package for concept scheme. An example of a category scheme is one which categorises data – sometimes known as a subject matter domain scheme or a data category scheme. Importantly, as will be seen later, the individual nodes in the scheme (the “categories”) can be associated to any set of IdentiableArtefacts in a Categorisation.

4.6.2 Class diagram Inheritance

Figure 23 Inheritance Class diagram of the Category Scheme

4.6.3 Explanation of the Diagram

4.6.3.1 Narrative

The categories are modelled as a hierarchical ItemScheme. The CategoryScheme inherits from the ItemScheme and has the following attributes:

id
uri
urn
version
validFrom
validTo
isExternalReference
structureURL
serviceURL
isPartial

Category inherits from Item and has the following attributes:

id
uri
urn

Both CategoryScheme and Category have the association to InternationalString to support a multi-lingual name, an optional multi-lingual description, and an association to Annotation to support notes (not shown on the model).

Through the inheritance the CategoryScheme comprise one or more Categorys, and the Category itself can have one or more child Category in the (inherited) hierarchy association. Note that a child Category can have only one parent Category in this association.

A partial CategoryScheme (where isPartial is set to “true”) is identical to a CategoryScheme and contains the Category and associated names and descriptions, just as in a normal CategoryScheme. However, its content is a subset of the full CategoryScheme. The way this works is described in section 3.5.3.1 on ItemScheme.

4.6.4 Class diagram Relationship

Figure 24: Relationship Class diagram of the Category Scheme

The CategoryScheme can have one or more Categorys. The Category is Identifiable and has identity information. A Category can have zero or more child Categorys, thus supporting a hierarchy of Categorys. Any IdentifiableArtefact can be +categorisedBy a Category. This is achieved by means of a Categorisation. Each Categorisation can associate one IdentifiableArtefact with one Category. Multiple Categorisations can be used to build a set of IdentifiableArtefacts that are +categorisedBy the same Category. Note that there is no navigation (i.e. no embedded reference) to the Categorisation from the Category. From an implementation perspective this is necessary as Categorisation has no effect on the versioning of either the CategoryScheme or the IdentifiableArtefact.

4.6.4.1 Definitions

4.7 Organisation Scheme

4.7.1 Class Diagram

Figure 25 The Organisation Scheme class diagram

4.7.2 Explanation of the Diagram

4.7.2.1 Narrative

The OrganisationScheme is abstract. It contains Organisation which is also abstract. The Organisation can have child Organisation.

The OrganisationScheme can be one of five types:

1. AgencyScheme – contains Agency which is restricted to a flat list of agencies (i.e., there is no hierarchy). Note that the SDMX system of (Maintenance) Agency can be hierarchic and this is explained in more detail in the SDMX Standards Section 6 “Technical Notes”.
2. DataProviderScheme – contains DataProvider which is restricted to a flat list of agencies (i.e., there is no hierarchy).
3. MetadataProviderScheme – contains MetadataProvider which is restricted to a flat list of agencies (i.e., there is no hierarchy).
4. DataConsumerScheme – contains DataConsumer which is restricted to a flat list of agencies (i.e., there is no hierarchy).
5. OrganisationUnitScheme – contains OrganisationUnit which does inherit the /hierarchy association from Organisation.

Reference metadata can be attached to the Organisation by means of the metadata attachment mechanism. This mechanism is explained in the Reference Metadata section of this document (see section 7). This means that the model does not specify the specific reference metadata that can be attached to a DataProvider, MetadataProvider, DataConsumer, OrganisationUnit or Agency, except for limited Contact information.

A partial OrganisationScheme (where isPartial is set to “true”) is identical to an OrganisationScheme and contains the Organisation and associated names and descriptions, just as in a normal OrganisationScheme. However, its content is a subset of the full OrganisationScheme. The way this works is described in section 3.5.3.1 on ItemScheme.

4.7.2.2 Definitions

4.8 Reporting Taxonomy

4.8.1 Class Diagram

Figure 26: Class diagram of the Reporting Taxonomy

4.8.2 Explanation of the Diagram

4.8.2.1 Narrative

In some data reporting environments, and in particular those in primary reporting, a report may comprise a variety of heterogeneous data, each described by a different Structure. Equally, a specific disseminated or published report may also comprise a variety of heterogeneous data. The definition of the set of linked sub reports is supported by the ReportingTaxonomy.

The ReportingTaxonomy is a specialised form of ItemScheme. Each ReportingCategory of the ReportingTaxonomy can link to one or more StructureUsage which itself can be one of Dataflow, or Metadataflow, and one or more Structure, which itself can be one of DataStructureDefinition or MetadataStructureDefinition. It is expected that within a specific ReportingTaxonomy each Category that is linked in this way will be linked to the same class (e.g. all Category in the scheme will link to a Dataflow). Note that a ReportingCategory can have child ReportingCategory and in this way it is possible to define a hierarchical ReportingTaxonomy. It is possible in this taxonomy that some ReportingCategory are defined just to give a reporting structure. For instance:

Section 1

1. linked to Datafow_1
2. linked to Datafow_2

Section 2

1. linked to Datafow_3
2. linked to Datafow_4

Here, the nodes of Section 1 and Section 2 would not be linked to Dataflow but the other would be linked to a Dataflow (and hence the DataStructureDefinition).

A partial ReportingTaxonomy (where isPartial is set to “true”) is identical to a ReportingTaxonomy and contains the ReportingCategory and associated names and descriptions, just as in a normal ReportingTaxonomy. However, its content is a sub set of the full ReportingTaxonomy The way this works is described in section 3.5.3.1 on ItemScheme.

4.8.2.2 Definitions

[1] The Codelist that extends 0..* Codelists is the 'extending' Codelist, while the Codelist(s) that are inherited is/are the 'extended' Codelist(s).