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Oracle Tips by Burleson

Database Deletion

Databases are deleted by shutting them down and then removing all of their associated files from the system. No command to perform this is provided by Oracle prior to Oracle9i. In Oracle9i, the DROP TABLESPACE command enables the DBA to drop the operating system files, as well as the logical database structures. The Database Creation Assistant (DBCA) does allow a DBA to remove a database in 8i and 9i. Let's look at an example using the DBCA on Linux.

The DBCA is started by issuing the DBCA command at the Oracle user in Linux or UNIX (or selecting it from the appropriate menu in Windows or NT.) The first screen that is displayed is shown in Figure 2.21. Select the Next button to display the Operations screen (see Figure 2.22). There, select the option Delete a Database and then select the Next button.

Welcome Screen of the Database Configuration Assistant

Operations screen of the Database Configuration Assistant.

The DBCA will display the Database screen next (shown in Figure 2.23). On the Database screen, select the database you wish to delete and then select the Next button.

Database screen of the Database Configuration Assistant.

Once you have made a database selection, the DBCA will show a Summary screen (shown in Figure 2.24) to give you a first chance to abort the deletion, just in case you chose the wrong database SID on the previous screen. Once you have verified that the database being deleted is in fact the one you want deleted, select the OK button to continue with the deletion process.

Summary Screen of the Database Configuration Assistant

After you select OK on the Summary screen, the DBCA program gives you one last chance to decide not to delete the instance. This screen isn't titled, so I call it the "Are you really, really sure" screen; it’s shown in Figure 2.25.. If you are really, really sure you want to delete the database, select Yes, and the delete operation will commence. This is the point of no return.

The "Are you really, really sure?" screen of the Database Configuration Assistant.

The next screen shown in the DBCA for the database deletion process displays the actual deletion status (Figure 2.26), that is, the progression through the various steps of deleting a database: connect, delete the instance and datafiles, and update network files. Following the final step, the DBCA automatically goes to the completion screen.

Database deletion status screen of the Database Configuration Assistant.

The final screen of the deletion process is the Database Deletion Completed screen )shown in Figure 2.27). It asks the question "Do you want to perform another operation?" The choices are Yes, to return to DBCA, or No, exit from DBCA. If you are done deleting databases, choose No.

Database deletion completion screen of the Database Configuration Assistant.

Manual Database Deletion

If you must manually delete a database, first log in as a DBA account, then use the following commands to get a listing of all the datafiles associate with the database:

See Code Depot

Once you have your file listing, shut down the database. And I suggest doing a complete, final backup (rest assured, someone will require something from this database sometime in the future) of the database before deleting it.