The metamodel database (MDB) records
- node/relationship/property structure of models;
- the official local vocabulary - terms that are employed in the backend data system;
- synonyms for local vocabulary mapped from external standards; and
- the value sets for properties with enumerated value domains, and data types for other properties.
The production instance of MDB contains a practical representation of a data model, in that it records the curated external terminology mappings and official sets of valid terms for each relevant property. In this way, the MDB is an extension of the MDF for any model it contains.
As the central location for official mappings to external vocabularies, the MDB can (should) be used as part of software modules that convert between the data physically stored in the production database and external standards. For example, an API known as the Simple Terminology Service STS, using MDB as its backend, is used for simple queries about a given model and validation of incoming data.
The bento-meta repository contains APIS for working with the MDB in Python and Perl.