oracle触发器实例讲解

oracle触发器实例讲解2008-11-27 09:17--[6]// Oracle Trigger ---------------------------------------------------------------------------------------------// --实例1------------------------ --创建触发器，当用户对test表执行DML语句时，将相关信息记录到日志表 --创建测试表 CREATE TABLE test ( t_id NUMBER(4), t_name VARCHAR2(20), t_age NUMBER(2), t_sex CHAR ); --创建记录测试表 CREATE TABLE test_log ( l_user VARCHAR2(15), l_type VARCHAR2(15), l_date VARCHAR2(30) ); --创建触发器 CREATE OR REPLACE TRIGGER test_trigger AFTER DELETE OR INSERT OR UPDATE ON test DECLARE v_type test_log.l_type%TYPE; BEGIN IF INSERTING THEN --INSERT触发 v_type := 'INSERT'; DBMS_OUTPUT.PUT_LINE('记录已经成功插入，并已记录到日志'); ELSIF UPDATING THEN --UPDATE触发 v_type := 'UPDATE'; DBMS_OUTPUT.PUT_LINE('记录已经成功更新，并已记录到日志'); ELSIF DELETING THEN v_type := 'DELETE'; DBMS_OUTPUT.PUT_LINE('记录已经成功删除，并已记录到日志'); END IF; INSERT INTO test_log VALUES(user,v_type, TO_CHAR(sysdate,'yyyy-mm-dd hh24:mi:ss')); END; / --下面我们来分别执行DML语句 INSERT INTO test VALUES(101,'zhao',22,'M'); UPDATE test SET t_age = 30 WHERE t_id = 101; DELETE test WHERE t_id = 101; --然后查看效果 SELECT * FROM test; SELECT * FROM test_log; --实例2------------------------ --创建触发器，它将映射emp表中每个部门的总人数和总工资 --创建映射表 CREATE TABLE dept_sal AS SELECT deptno,COUNT(empno) AS total_emp,SUM(sal) AS total_sal FROM emp GROUP BY deptno; DESC dept_sal; --创建触发器 CREATE OR REPLACE TRIGGER emp_info AFTER INSERT OR UPDATE OR DELETE ON emp DECLARE CURSOR cur_emp IS SELECT deptno,COUNT(empno) AS total_emp,SUM(sal) AS total_sal FROM emp GROUP BY deptno; BEGIN DELETE dept_sal; --触发时首先删除映射表信息 FOR v_emp IN cur_emp LOOP --DBMS_OUTPUT.PUT_LINE(v_emp.deptno || v_emp.total_emp || v_emp.total_sal); --插入数据 INSERT INTO dept_sal VALUES(v_emp.deptno,v_emp.total_emp,v_emp.total_sal); END LOOP; END; / --对emp表进行DML操作 INSERT INTO emp(empno,deptno,sal) VALUES('123','10',10000); SELECT * FROM dept_sal; DELETE EMP WHERE empno=123; SELECT * FROM dept_sal; --实例3------------------------ --创建触发器，它记录表的删除数据 --创建表 CREATE TABLE employee ( id VARCHAR2(4) NOT NULL, name VARCHAR2(15) NOT NULL, age NUMBER(2) NOT NULL, sex CHAR NOT NULL ); DESC employee; --插入数据 INSERT INTO employee VALUES('e101','zhao',23,'M'); INSERT INTO employee VALUES('e102','jian',21,'F'); --创建记录表 CREATE TABLE old_employee AS SELECT * FROM employee; DESC old_employee; --创建触发器 CREATE OR REPLACE TRIGGER tig_old_emp AFTER DELETE ON employee -- FOR EACH ROW --语句级触发，即每一行触发一次 BEGIN INSERT INTO old_employee VALUES(:old.id,:old.name,:old.age,:old.sex); --:old代表旧值 END; / --下面进行测试 DELETE employee; SELECT * FROM old_employee; --实例4------------------------ --创建触发器，利用视图插入数据 --创建表 CREATE TABLE tab1 (tid NUMBER(4) PRIMARY KEY,tname VARCHAR2(20),tage NUMBER(2)); CREATE TABLE tab2 (tid NUMBER(4),ttel VARCHAR2(15),tadr VARCHAR2(30)); --插入数据 INSERT INTO tab1 VALUES(101,'zhao',22); INSERT INTO tab1 VALUES(102,'yang',20); INSERT INTO tab2 VALUES(101,'13761512841','AnHuiSuZhou'); INSERT INTO tab2 VALUES(102,'13563258514','AnHuiSuZhou'); --创建视图连接两张表 CREATE VIEW tab_view AS SELECT tab1.tid,tname,ttel,tadr FROM tab1,tab2 WHERE tab1.tid = tab2.tid; --创建触发器 CREATE OR REPLACE TRIGGER tab_trigger INSTEAD OF INSERT ON tab_view BEGIN INSERT INTO tab1(tid,tname) VALUES(:new.tid,:new.tname); INSERT INTO tab2(ttel,tadr) VALUES(:new.ttel,:new.tadr); END; / --现在就可以利用视图插入数据 INSERT INTO tab_view VALUES(105,'zhaoyang','13886681288','beijing'); --查看效果 SELECT * FROM tab_view; --实例5------------------------ --创建触发器，比较emp表中更新的工资 CREATE OR REPLACE TRIGGER sal_emp BEFORE UPDATE ON emp FOR EACH ROW BEGIN IF :OLD.sal > :NEW.sal THEN DBMS_OUTPUT.PUT_LINE('工资减少'); ELSIF :OLD.sal < :NEW.sal THEN DBMS_OUTPUT.PUT_LINE('工资增加'); ELSE DBMS_OUTPUT.PUT_LINE('工资未作任何变动'); END IF; DBMS_OUTPUT.PUT_LINE('更新前工资 ：' || :OLD.sal); DBMS_OUTPUT.PUT_LINE('更新后工资 ：' || :NEW.sal); END; / --执行UPDATE查看效果 UPDATE emp SET sal = 3000 WHERE empno = '7788'; --实例6------------------------ --创建触发器，将操作CREATE、DROP存储在log_info表 --创建表 CREATE TABLE log_info ( manager_user VARCHAR2(15), manager_date VARCHAR2(15), manager_type VARCHAR2(15), obj_name VARCHAR2(15), obj_type VARCHAR2(15) ); --创建触发器 CREATE OR REPLACE TRIGGER trig_log_info AFTER CREATE OR DROP ON SCHEMA BEGIN INSERT INTO log_info VALUES(USER,SYSDATE,SYS.DICTIONARY_OBJ_NAME,SYS.DICTIONARY_OBJ_OWNER, SYS.DICTIONARY_OBJ_TYPE); END; / --测试语句 CREATE TABLE a(id NUMBER); CREATE TYPE aa AS OBJECT(id NUMBER); / DROP TABLE a; DROP TYPE aa; --查看效果 SELECT * FROM log_info; --相关数据字典-----------------------------------------------------// SELECT * FROM USER_TRIGGERS; SELECT * FROM ALL_TRIGGERS; SELECT * FROM DBA_TRIGGERS; --必须以DBA身份登陆才能使用此数据字典 --启用和禁用 ALTER TRIGGER trigger_name DISABLE; ALTER TRIGGER trigger_name ENABLE;