ORACLE触发器实例

港控/mmm° 2022-07-12 15:48 202阅读 0赞

**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 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;

**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 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;

**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 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;

**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 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;

**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'); 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';

**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 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;