5 Metadata Structure Definition (MSD)

5.1 Scope

The scope of the MSD is enhanced in this version to better support the types of construct to which metadata can be attached. In particular it is possible to specify an attachment to any key or partial key of a data set. This is particularly useful for web dissemination where metadata may be present for the data, but is not stored with the data but is related to it. For this use case to be supported it is necessary to be able to specify in the MSD that metadata is attached to a key or partial key, and the actual key or partial key to be identified in the Metadata Set.

In addition to the increase in the scope of objects that can be included in an MSD, the way the identifier mechanism works in this version, and the terminology used, is much simpler.

5.2 Identification of the Object Type to which the Metadata is to be Attached

The following example shows the structure and naming of the MSD components for the use case of defining full and partial keys.

The schematic structure of an MSD is shown below.

Figure 1: Schematic of the Metadata Structure Definition

The MSD comprises the specification of the object types to which metadata can be reported in a Metadata Set (Metadata Target(s)), and the Report Structure(s) comprising the Metadata Attributes that identify the Concept for which metadata may be reported in the Metadata Set. Importantly, one Report Structure references the Metadata Target for which it is relevant. One Report Structure can reference many Metadata Target i.e. the same Report Structure can be used for different target objects.

Figure 2: Example MSD showing Metadata Targets

Note that the SDMX-ML schemas have explicit XML elements for each identifiable object type because identifying, for instance, a Maintainable Object has different properties from an Identifiable Object which must also include the agencyId, version, and id of the Maintainable Object in which it resides.

5.3 Report Structure

An example is shown below.

Figure 3: Example MSD showing specification of three Metadata Attributes

This example shows the following hierarchy of Metadata Attributes:

Source – this is presentational and no metadata is expected to be reported at this level

• Source Type
• Collection Source Name

5.4 Metadata Set

An example of reporting metadata according to the MSD described above, is shown below.

Figure 4: Example Metadata Set This example shows:

1. The reference to the MSD, Metadata Report, and Metadata Target (MetadataTargetValue)
2. The reported metadata attributes (AttributeValueSet)