oracle sequence delete

Oracle sequence is a very commonly used database object used to generate unique self-increasing numbers. However, in some cases you may need to delete a sequence. This may be because you no longer need it, or you need to recreate it. In any case, deleting a sequence is a relatively simple operation. Below, this article will introduce you how to delete a sequence in Oracle database.

Step 1: Determine the sequence to be deleted

Before deleting a sequence, you need to confirm the name of the sequence to be deleted. You can view all available sequences using the following command:

SELECT sequence_name FROM user_sequences;

When you use this command, Oracle will return a list containing all sequence names. You can select the sequence to delete.

Step 2: Stop using the sequence

Before deleting a sequence, you need to stop using it. If a table is using this sequence, it cannot be deleted. Use the following command to check if a table is using this sequence:

SELECT table_name FROM user_tab_columns WHERE column_name = 'YOUR_SEQUENCE_NAME';

If any table is using this sequence, you will need to modify the table first. You can use the following command to modify the table so that it no longer uses this sequence:

ALTER TABLE YOUR_TABLE_NAME MODIFY (YOUR_COLUMN_NAME DEFAULT NULL);

This command will set the default value of the column that uses this sequence to NULL, which will stop the automatic growth of the column.

Step 3: Delete the sequence

Once your sequence is no longer in use, you can use the following command to delete it:

DROP SEQUENCE YOUR_SEQUENCE_NAME;

Please make sure the sequence name you entered is correct , otherwise you will remove the wrong sequence.

When you use this command, Oracle deletes the sequence and releases all resources allocated to the sequence. After you delete a sequence, you can no longer access the sequence.

In this article, we have introduced the steps to delete sequences in Oracle database. Deleting a sequence is a relatively simple operation, just follow the steps above. Before deleting a sequence, make sure it is no longer in use and enter your commands carefully.

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