schema version

A schema version is a database version for a dictionary or a module. A schema version is set of schema definitions, which are valid until a certain time point. Schema versions are created for a dictionary or resource database as a whole, i.e. one cannot define a schema version for a single structure. Schema versioning allows on line schema evolution of a database, since structure instances are updated automatically to new schema versions.

Any number of schema versions can be defined for a dictionary. Schema versions are numbered consecutively and associated with a version date.