system catalog[′sis·təm ′kad·əl‚äg]
An index of all files controlled by the operating system of a large computer.
McGraw-Hill Dictionary of Scientific & Technical Terms, 6E, Copyright © 2003 by The McGraw-Hill Companies, Inc.
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.
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