Figure 7: Instead Of trigger providing updateable join support

CREATE VIEW empdept AS 

      SELECT empno, firstname, lastname, deptname 

        FROM employee, department

        WHERE workdept=deptno



CREATE TRIGGER UpdateJoin 

 INSTEAD OF UPDATE ON empdept

REFERENCING OLD ROW AS o NEW ROW AS n

 FOR EACH ROW

BEGIN 

  UPDATE employee

        SET empno=n.empno, firstname=n.firstname, lastname=n.lastname

        WHERE empno=o.empno;



  IF (o.deptname <> n.deptname) THEN

    UPDATE department

       SET deptname = n.deptname

       WHERE deptname=o.deptname;

  END IF;

END;