Dropping a Constraint

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You can use Object Browser to drop constraints from a table. Although you do not have to disable a constraint before dropping it, you can determine whether the constraint can be dropped by attempting to disable it first. If a constraint in a parent table enforces a foreign key constraint in a child table, and if the child table contains dependent rows, then the constraint cannot always be disabled or dropped.

Continuing with the current example, you drop the check constraint that you created earlier in the section, "Adding a Check Constraint".

To drop a constraint:

1. Log in to the Database Home Page. See "Logging in to the Database Home Page".

2. On the Database Home Page, click the Object Browser icon.

3. In the Object list, select Tables then click the personal_info table that you previously created.

4. Click the Constraints tab.

5. Click the Drop button.

6. On the Drop Constraint page, select the check constraint that was created on the contact_email column that specifies a NOT NULL constraint. See "Viewing Existing Constraints" to determine the name of the constraint, such as SYS_C004180.

7. Click the Next button.

8. Click the Finish button to complete the action.