CREATE OR REPLACE TRIGGER trg_update_view_3
INSTEAD OF UPDATE
ON dept_sal
FOR EACH ROW
DECLARE
  dno INTEGER;
  diff INTEGER;
  countemp INTEGER;
BEGIN
  IF ( NOT :NEW.DNAME = :old.DNAME ) THEN
    UPDATE dept
    SET DNAME = :NEW.DNAME
    WHERE DNAME = :old.DNAME;
  END IF;
  IF ( NOT :NEW.SUMSAL = :old.SUMSAL ) THEN
    SELECT deptno INTO dno
    FROM dept
    WHERE dname = :old.DNAME;

    DBMS_OUTPUT.put_line(dno);

    SELECT COUNT(empno) INTO countemp
    FROM emp
    WHERE deptno = dno;

    DBMS_OUTPUT.put_line(countemp);

    INSERT INTO deptemp VALUES(dno, countemp);

    diff := (:NEW.SUMSAL - :old.SUMSAL) / countemp;

    UPDATE emp
    SET SAL = SAL + diff
    WHERE deptno = dno;
  END IF;
END;
/