本文介绍了一个数据库触发器，该触发器在部门表(dept)上进行删除或更新操作前触发。若为删除操作，则同步删除员工表(emp)中对应部门的所有记录；若为更新操作，则更新员工表中对应部门编号。
CREATE OR REPLACE TRIGGER tre_del_update
BEFORE DELETE OR UPDATE ON dept FOR EACH ROW
BEGIN
IF DELETING THEN
DELETE FROM emp WHERE deptno=:old.deptno;
ELSIF updating THEN
UPDATE emp SET deptno=:NEW.deptno WHERE deptno=:OLD.deptno;
END IF;
END tre_del_update;
BEFORE DELETE OR UPDATE ON dept FOR EACH ROW
BEGIN
IF DELETING THEN
DELETE FROM emp WHERE deptno=:old.deptno;
ELSIF updating THEN
UPDATE emp SET deptno=:NEW.deptno WHERE deptno=:OLD.deptno;
END IF;
END tre_del_update;
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