System catalog views

The database manager maintains a set of tables and views that contain information about the data under its control. These tables and views are collectively known as the system catalog.

The system catalog contains information about the logical and physical structure of database objects such as tables, views, indexes, packages, and functions. It also contains statistical information. The database manager ensures that the descriptions in the system catalog are always accurate.

The system catalog views are like any other database view. SQL statements can be used to query the data in the system catalog views. A set of updatable system catalog views can be used to modify certain values in the system catalog.