System catalog tables v15
The system catalog tables contain definitions of database objects that are available to EDB Postgres Advanced Server. The layout of the system tables is subject to change. If you're writing an application that depends on information stored in the system tables, it's prudent to use an existing catalog view or create a catalog view to isolate the application from changes to the system table.
For detailed information about the system catalog tables, see the Database Compatibility for Oracle Developers Catalog Views.