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...What is the Dictionary?


Notes:

The static and dynamic views built on the SYS tables are user-friendly. “USER_TABLES”, for example, contains one row for every table owned by you (i.e. created in your schema).
In this lesson, you will learn about static views and dynamic views. Other types of dictionary views are also available:
Global dynamic views are used in Oracle Parallel Server environments (called Real Applications Clusters in Oracle9i).
The “X$” views are undocumented views, and are typically used by the database itself or Oracle support.
Refer to the Oracle9i Database Reference for descriptions of all documented dictionary views.
Optional Mini-Workshop
To become familiar with USER_TABLES, and the data dictionary in general, execute the following two commands from a SQL*Plus session while connected with your DBA userid:
desc user_tables
select table_name, num_rows from user_tables;