oracle高级用法之触发器

/* 实施复杂的安全性检查：禁止在非工作时间插入员工 */
create or replace trigger securityemp
before insert
on emp
begin
if to_char(sysdate,'day') in ('星期六','星期天') or
to_number(to_char(sysdate,'hh24')) not between 9 and 18 then
raise_application_error(-20001,'禁止在非工作时间插入新员工');
end if;
end;


-- 删除触发器
drop trigger securityemp;


insert into emp (empno,ename,sal,deptno) values(1001,'libing',8000,10);


/* 数据的确认：涨后的薪水不能少于涨前的薪水 */
create or replace trigger checksalary
before update
on emp
for each row
begin
if :new.sal < :old.sal then
raise_application_error('20002','涨后的薪水不能少于涨前的薪水:||:new.sal||:old.sal');
end if;
end;


update emp t set t.sal = t.sal -1 where t.ename = 'libing';


/* 数据的审计：涨后的工资超过6000，审计该员工 */
-- 创建审计表
create table audit_info(
information varchar2(200)
);


create or replace trigger do_audit_emp_salary
after update
on emp
for each row
begin
if :new.sal > 6000 then
insert into audit_info values(:new.empno||' '||:new.ename||' '||:new.sal);
end if;
end;


update emp t set t.sal = t.sal + 1 where t.ename = 'libing';


commit;


select * from audit_info;


/* 实现数据的同步和备份:给员工涨完工资后，自动备份工资到备份表 */ -- 创建备份表 create table emp_back as select * from emp; create or replace trigger sync_salary after update on emp for each row begin update emp_back set sal=:new.sal where empno =:new.empno; end; update emp set sal=sal+10 where empno=1001;

原文地址：https://www.jb51.cc/oracle/208079.html