11 Data Provisioning

11.1 Class Diagram

Figure 41: Relationship and inheritance class diagram of data provisioning

11.2 Explanation of the Diagram

11.2.1 Narrative

This sub model links many artefacts in the SDMX-IM and is pivotal to an SDMX metadata registry, as all of the artefacts in this sub model must be accessible to an application that is responsible for data and metadata registration or for an application that requires access to the data or metadata.

Whilst a registry contains all of the metadata depicted on the diagram above, the classes in the grey shaded area are specific to a registry based scenario where data sources (either physical data and metadata sets or databases and metadata repositories) are registered. More details on how these classes are used in a registry scenario can be found in the SDMX Registry Interface document. (Section 5 of the SDMX Standards).

A ProvisionAgreement links the artefact that defines how data and metadata are structured and classified (StructureUsage) to the DataProvider, and, by means of a data or metadata registration, it references the Datasource (this can be data or metadata), whether this be an SDMX conformant file on a website (SimpleDatasource) or a database service capable of supporting an SDMX query and responding with an SDMX conformant document (QueryDatasource).

The StructureUsage, which has concrete classes of DataflowDefinition and MetadataflowDefinition identifies the corresponding DataStructureDefinition or MetadataStructureDefinition, and, via Categorisation, can link to one or more Category in a CategoryScheme such as a subject matter domain scheme, by which the StructureUsage can be classified. This can assist in drilling down from subject matter domains to find the data or metadata that may be relevant.

The SimpleDatasource links to the actual DataSet or MetadataSet on a website (this is shown on the diagram as a dependency called “references”). The sourceURL is obtained during the registration process of the DataSet or the MetadataSet. Additional information about the content of the SimpleDatasource is stored in the registry in terms of a ContentConstraint (see 10.3) for the Registration.

The QueryDatasource is an abstract class that represents a data source which can understand an SDMX-ML query (SOAPDatasource) or RESTful query (RESTDatasource) and respond appropriately. Each of these different Datasources inherit the dataURL from Datasource, and the QueryDatasource has an additional URL to locate a WSDL or WADL document to describe how to access it. All other supported protocols are assumed to use the SimpleDatasource URL.

The diagram below shows in schematic way the essential navigation through the SDMX structural artefacts that eventually link to a data or metadata registration.

Figure 42: Schematic of the linking of structural metadata to data and metadata registration

11.2.2 Definitions