用oracle触发器删数据6,oracle触发器运用

oracle触发器应用

--[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;

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