ORACLE触发器实例

一、test表执行DML语句时，将相关信息记录到日志表test_log
–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<br /> CREATE OR REPLACE TRIGGER test_trigger<br /> AFTER DELETE OR INSERT OR UPDATE ON test<br /> DECLARE v_type test_log.l_type%TYPE;<br /> BEGIN<br /> IF INSERTING THEN<br /> –INSERT触发<br /> v_type := ‘INSERT’;<br /> DBMS_OUTPUT.PUT_LINE(‘记录已经成功插入，并已记录到日志’);<br /> ELSIF UPDATING THEN<br /> –UPDATE触发<br /> v_type := ‘UPDATE’;<br /> DBMS_OUTPUT.PUT_LINE(‘记录已经成功更新，并已记录到日志’);<br /> ELSIF DELETING THEN v_type := ‘DELETE’;<br /> DBMS_OUTPUT.PUT_LINE(‘记录已经成功删除，并已记录到日志’);<br /> END IF;<br /> INSERT INTO test_log VALUES(user,v_type, TO_CHAR(sysdate,’yyyy-mm-dd hh24:mi:ss’));<br /> 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;

二、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<br /> CREATE OR REPLACE TRIGGER emp_info<br /> AFTER INSERT OR UPDATE OR DELETE ON emp<br /> DECLARE CURSOR cur_emp IS<br /> SELECT deptno,COUNT(empno) AS total_emp,SUM(sal) AS total_sal FROM emp GROUP BY deptno;<br /> BEGIN DELETE dept_sal;<br /> –触发时首先删除映射表信息<br /> FOR v_emp IN cur_emp LOOP<br /> –DBMS_OUTPUT.PUT_LINE(v_emp.deptno || v_emp.total_emp || v_emp.total_sal);<br /> –插入数据<br /> INSERT INTO dept_sal VALUES(v_emp.deptno,v_emp.total_emp,v_emp.total_sal);<br /> END LOOP;<br /> 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;

三、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<br /> CREATE OR REPLACE TRIGGER tig_old_emp<br /> AFTER DELETE ON employee<br /> FOR EACH ROW<br /> –语句级触发，即每一行触发一次<br /> BEGIN<br /> INSERT INTO old_employee<br /> VALUES(:old.id,:old.name,:old.age,:old.sex);<br /> –:old代表旧值<br /> END;

–下面进行测试
DELETE employee;
SELECT * FROM old_employee;

四、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<br /> CREATE OR REPLACE TRIGGER tab_trigger<br /> INSTEAD OF INSERT ON tab_view<br /> BEGIN<br /> INSERT INTO tab1(tid,tname) VALUES(:new.tid,:new.tname);<br /> INSERT INTO tab2(ttel,tadr) VALUES(:new.ttel,:new.tadr);<br /> 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;

五、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’);<br /> ELSIF :OLD.sal < :NEW.sal THEN DBMS_OUTPUT.PUT_LINE(‘工资增加’);<br /> ELSE DBMS_OUTPUT.PUT_LINE(‘工资未作任何变动’);<br /> END IF;<br /> DBMS_OUTPUT.PUT_LINE(‘更新前工资 ：’ || :OLD.sal);<br /> DBMS_OUTPUT.PUT_LINE(‘更新后工资 ：’ || :NEW.sal);<br /> END;
–执行UPDATE查看效果
UPDATE emp SET sal = 3000 WHERE empno = ‘7788’;

六、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<br /> CREATE OR REPLACE TRIGGER trig_log_info<br /> AFTER CREATE OR DROP ON SCHEMA<br /> BEGIN INSERT INTO log_info<br /> VALUES(USER,SYSDATE,SYS.DICTIONARY_OBJ_NAME,SYS.DICTIONARY_OBJ_OWNER, SYS.DICTIONARY_OBJ_TYPE);<br /> 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;