Managing Tables   «Prev 

Querying the Data Dictionary

The central set of tables and views that are used as a read-only reference about a particular database. A data dictionary stores such information as:
  1. The logical and physical structure of the database
  2. Valid users of the database
  3. Information about integrity constraints
  4. How much space is allocated for a schema object and how much of it is in use
A data dictionary is created when a database is created and is automatically updated when the structure of the database is updated.

1) You bring up SQL Plus, the standard interactive tool for Oracle, here using the standard SCOTT/TIGER username and password
You bring up SQL Plus, the standard interactive tool for Oracle, here using the standard SCOTT/TIGER username and password set up

2) You enter this SQL statement to return a list of table names and the number of rows in the table
You enter this SQL statement to return a list of table names and the number of rows in the table.

3) The result is the list of table names, but it does not show the number of rows, as this table has not had the ANALYZE command run on it to gather statistics.
The result is the list of table names, but it does not show the number of rows, as this table has not had the ANALYZE command run on it to gather statistics