Example: Deleting a Table Constraint

You can delete constraints from a table with Database Control. Deleting a table constraint may cause the deletion of other constraints. For example, if you delete the primary key constraint from a table (the parent table) that is referenced in a foreign key constraint in another table (the child table), then the foreign key constraint in the child table is also deleted through a cascading delete mechanism.

In this example, you delete the check constraint that you created for the purchase_orders table in "Example: Adding a New Table Constraint".

To delete a constraint from the PURCHASE_ORDERS table:

1. Go to the Database Home page, logging in as user nick or as user SYSTEM.

   See "Accessing the Database Home Page".

2. At the top of the page, click Schema to view the Schema subpage.

3. In the Database Objects section, click Tables

   The Tables page appears.

4. In the Schema field, enter NICK and then click Go.

   All tables owned by user NICK are displayed.

5. Select the PURCHASE_ORDERS table, and then click Edit.

   The Edit Table page appears.

6. Click Constraints to display the Constraints subpage.

7. Select the constraint named PO_CHECK_RCVD_DATE, and then click Delete.

   The check constraint is removed from the list.

8. Click Apply.

   A confirmation message appears.