oracle的行级触发器使用

CREATE   TABLE  emp_his  AS   SELECT   *   FROM  EMP  WHERE   1 = 2 ; 
CREATE   OR   REPLACE   TRIGGER  tr_del_emp 
   BEFORE  DELETE   -- 指定触发时机为删除操作前触发
    ON  scott.emp 
    FOR  EACH ROW    -- 说明创建的是行级触发器 
BEGIN
    -- 将修改前数据插入到日志记录表 del_emp ,以供监督使用。
    INSERT   INTO  emp_his(deptno , empno, ename , job ,mgr , sal , comm , hiredate )
        VALUES ( :old.deptno, :old.empno, :old.ename , :old.job,:old.mgr, :old.sal, :old.comm, :old.hiredate );
END ;
DELETE  emp  WHERE  empno = 7788 ;
DROP   TABLE  emp_his;
DROP   TRIGGER  del_emp;

CREATE   OR   REPLACE   TRIGGER  tr_dept_time
BEFORE  INSERT   OR   DELETE   OR   UPDATE  
ON  departments
BEGIN
  IF  (TO_CHAR(sysdate, ' DAY ' )  IN  ( ' 星期六 ' ,  ' 星期日 ' ))  OR  (TO_CHAR(sysdate,  ' HH24:MI ' )  NOT   BETWEEN   ' 08:30 '   AND   ' 18:00 ' )  THEN
     RAISE_APPLICATION_ERROR( - 20001 ,  ' 不是上班时间，不能修改departments表 ' );
  END   IF ;
END ;

CREATE   OR   REPLACE   TRIGGER  tr_emp_sal_comm
BEFORE  UPDATE   OF  salary, commission_pct
        OR   DELETE
ON  HR.employees
FOR  EACH ROW
WHEN  (old.department_id  =   80 )
BEGIN
      WHEN  UPDATING ( ' salary ' )  THEN
         IF  :NEW.salary  <  :old.salary  THEN
           RAISE_APPLICATION_ERROR( - 20001 ,  ' 部门80的人员的工资不能降 ' );
         END   IF ;
      WHEN  UPDATING ( ' commission_pct ' )  THEN
         IF  :NEW.commission_pct  <  :old.commission_pct  THEN
           RAISE_APPLICATION_ERROR( - 20002 ,  ' 部门80的人员的奖金不能降 ' );
         END   IF ;
      WHEN  DELETING  THEN
          RAISE_APPLICATION_ERROR( - 20003 ,  ' 不能删除部门80的人员记录 ' );
      END   CASE ;
END ; 

CREATE   OR   REPLACE   TRIGGER  tr_reg_cou
AFTER  update   OF  region_id
ON  regions
FOR  EACH ROW
BEGIN
 DBMS_OUTPUT.PUT_LINE( ' 旧的region_id值是 ' || :old.region_id
                   || ' 、新的region_id值是 ' || :new.region_id);
  UPDATE  countries  SET  region_id  =  :new.region_id
  WHERE  region_id  =  :old.region_id;
END ;

CREATE   OR   REPLACE   PROCEDURE  add_job_history
 ( p_emp_id          job_history.employee_id % type
   , p_start_date      job_history.start_date % type
  , p_end_date        job_history.end_date % type
   , p_job_id          job_history.job_id % type
   , p_department_id   job_history.department_id % type
BEGIN
  INSERT   INTO  job_history (employee_id, start_date, end_date,
                           job_id, department_id)
   VALUES (p_emp_id, p_start_date, p_end_date, p_job_id, p_department_id);
END  add_job_history;
-- 创建触发器调用存储过程...
CREATE   OR   REPLACE   TRIGGER  update_job_history