could be used as an extension for performing data definition tasks on
databases, and to control the access rights on database objects.
It may be implemented by a database driver provider, to encapsulate the
complexity of data definition, and to give a common way for data definition as
the DDL of most DBMS's differs.
At least, the access to the tables of a database should be implemented.
The implementation of other known database objects like views is optional.
To control the access rights of users, there is the possibility to
implement objects like users and groups.
