Example: Removing constraints

 

When you remove the primary key over the DEPTNO column in the DEPARTMENT table, other tables are affected. You also remove the REPORTS_TO_EXISTS constraint that is defined on the DEPARTMENT table and the WORKDEPT_EXISTS constraint that is defined on the EMPLOYEE table, because the primary key that you remove is the parent key in those constraint relationships.

    ALTER TABLE CORPDATA.EMPLOYEE DROP PRIMARY KEY

You can also remove a constraint by name, as in the following example:

    ALTER TABLE CORPDATA.DEPARTMENT                   DROP CONSTRAINT UNIQUE_LNAME_IN_DEPT

 

Parent topic:

Creating a table