試題詳解

QUESTION 109 Which code can you use to ensure that the salary is not increased by more than 10% at a time nor is it ever decreased?
(A) ALTER TABLE emp ADD CONSTRAINT ck_sal CHECK (sal BETWEEN sal AND sal*1.1);
(B) CREATE OR REPLACE TRIGGER check_sal BEFORE UPDATE OF sal ON emp FOR EACH ROW WHEN (new.sal < old.sal OR new.sal > old.sal * 1.1) BEGIN RAISE_APPLICATION_ERROR ( - 20508, 'Do not decrease salary not increase by more than 10%'); END;
(C) CREATE OR REPLACE TRIGGER check_sal BEFORE UPDATE OF sal ON emp WHEN (new.sal < old.sal OR new.sal > old.sal * 1.1) BEGIN RAISE_APPLICATION_ERROR ( - 20508, 'Do not decrease salary not increase by more than 10%'); END;
(D) CREATE OR REPLACE TRIGGER check_sal AFTER UPDATE OR sal ON emp WHEN (new.sal < old.sal OR -new.sal > old.sal * 1.1) BEGIN RAISE_APPLICATION_ERROR ( - 20508, 'Do not decrease salary not increase by more than 10%'); END;