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Common DBA Views


Notes:

Here is a short-list of commonly used static data dictionary views. Do not try to remember every detail about these views now; you will use these views in subsequent lessons in this course. Here’s a brief description of some commonly used dictionary views:
DBA_TABLES contains one row for every table and includes information such as owner, tablespace_name, number of rows (NUM_ROWS) and average row length (AVG_ROW_LEN). NUM_ROWS and AVG_ROW_LEN are statistics and must be created and maintained with DBMS_STATS (formerly ANALYZE).
DBA_TAB_COLUMNS contains one row for every column of every table. It contains useful information such as data type, length, precision and scale, and average length.
DBA_CONSTRAINTS contains one row for every constraint created in the database. DBA_CONSTRAINTS contains details such as the type of (“P” for primary key, “C” for check and not null constraints, etc.) and status of the constraint.
DBA_CONS_COLUMNS contains the column names the constraint is built on.
Notes for this slide continue on the next page…