ATAbase> The dATA dictionary of a DBMS. The system cATAlogue stores meta-dATA including the schemas of the dATAbases. It is a mini-dATAbase, and is usually stored using the DBMS itself in special tables called {system tables}. It maybe referred to as being "on line", as it is active, and can be queried by users like any other table. (1999-04-27)