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Data elements in successive versions of a model are linked, unless modified. If a data element in another model is linked to a data element in an old version, then an indirect link will exist to the corresponding data element in the new version. The automatic creation of a direct link would not be appropriate, as the intended relationship may no longer apply.
Links
Two different data elements, in two different models, may be related. For example, a data element in a database model may be based upon a data element in a data standard, as a specification that the database design should follow. Alternatively, a data element in a research dataset may be based upon a data element in a database model, in the expectation that the data could then be extracted from an existing information system.
The model catalogue can be used to record this information, as a link between the data elements in the two different models.
It can be used also to record relationships between groups of data elements, if a class of data elements in one model has been based upon a class of data elements in another.