--實例1------------------------
--創建觸發器，當用戶對test表執行DML語句時，將相關信息記錄到日志表
--創建測試表
CREATE TABLE test
(
t_id NUMBER(4),
t_name VARCHAR2(20),
t_age NUMBER(2),
t_sex CHAR
);
--創建記錄測試表
CREATE TABLE test_log
(
l_user VARCHAR2(15),
l_type VARCHAR2(15),
l_date VARCHAR2(30)
);
--創建觸發器
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觸發
v_type := 'INSERT';
DBMS_OUTPUT.PUT_LINE('記錄已經成功插入，并已記錄到日志');
ELSIF UPDATING THEN --UPDATE觸發
v_type := 'UPDATE';
DBMS_OUTPUT.PUT_LINE('記錄已經成功更新，并已記錄到日志');
ELSIF DELETING THEN
v_type := 'DELETE';
DBMS_OUTPUT.PUT_LINE('記錄已經成功刪除，并已記錄到日志');
END IF;
INSERT INTO test_log VALUES(user,v_type,
TO_CHAR(sysdate,'yyyy-mm-dd hh24:mi:ss'));
END;
/
--下面我們來分別執行DML語句
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;
--實例2------------------------
--創建觸發器，它將映射emp表中每個部門的總人數和總工資
--創建映射表
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;
--創建觸發器
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; --觸發時首先刪除映射表信息
FOR v_emp IN cur_emp LOOP
--DBMS_OUTPUT.PUT_LINE(v_emp.deptno || v_emp.total_emp || v_emp.total_sal);
--插入數據
INSERT INTO dept_sal
VALUES(v_emp.deptno,v_emp.total_emp,v_emp.total_sal);
END LOOP;
END;
/
--對emp表進行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;
--實例3------------------------
--創建觸發器，它記錄表的刪除數據
--創建表
CREATE TABLE employee
(
id VARCHAR2(4) NOT NULL,
name VARCHAR2(15) NOT NULL,
age NUMBER(2) NOT NULL,
sex CHAR NOT NULL
);
DESC employee;
--插入數據
INSERT INTO employee VALUES('e101','zhao',23,'M');
INSERT INTO employee VALUES('e102','jian',21,'F');
--創建記錄表
CREATE TABLE old_employee AS
SELECT * FROM employee;
DESC old_employee;
--創建觸發器
CREATE OR REPLACE TRIGGER tig_old_emp
AFTER DELETE ON employee --
FOR EACH ROW --語句級觸發，即每一行觸發一次
BEGIN
INSERT INTO old_employee
VALUES(:old.id,:old.name,:old.age,:old.sex); --:old代表舊值
END;
/
--下面進行測試
DELETE employee;
SELECT * FROM old_employee;
--實例4------------------------
--創建觸發器，利用視圖插入數據
--創建表
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));
--插入數據
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');
--創建視圖連接兩張表
CREATE VIEW tab_view AS
SELECT tab1.tid,tname,ttel,tadr FROM tab1,tab2
WHERE tab1.tid = tab2.tid;
--創建觸發器
CREATE OR REPLACE TRIGGER tab_trigger
INSTEAD OF INSERT ON tab_view
BEGIN
INSERT INTO tab1(tid, tname, tage) VALUES(:new.tid, :new.tname, :new.tage);
INSERT INTO tab2(tid, ttel, tadr) VALUES(:new.tid, :new.ttel, :new.tadr);
END;
/
--現在就可以利用視圖插入數據
INSERT INTO tab_view VALUES(105, 'smith', 23, '13678987649', 'hongkong');
--查看效果
SELECT * FROM tab_view;
--實例5------------------------
--創建觸發器，比較emp表中更新的工資
CREATE OR REPLACE TRIGGER sal_emp
BEFORE UPDATE ON emp
FOR EACH ROW
BEGIN
IF :OLD.sal > :NEW.sal THEN
DBMS_OUTPUT.PUT_LINE('工資減少');
ELSIF :OLD.sal < :NEW.sal THEN
DBMS_OUTPUT.PUT_LINE('工資增加');
ELSE
DBMS_OUTPUT.PUT_LINE('工資未作任何變動');
END IF;
DBMS_OUTPUT.PUT_LINE('更新前工資 ：' || :OLD.sal);
DBMS_OUTPUT.PUT_LINE('更新后工資 ：' || :NEW.sal);
END;
/
--執行UPDATE查看效果
UPDATE emp SET sal = 3000 WHERE empno = '7788'; // execute "SET SERVEROUTPUT ON" before execute it.
--實例6------------------------
--創建觸發器，將操作CREATE、DROP存儲在log_info表
--創建表
CREATE TABLE log_info
(
manager_user VARCHAR2(15),
manager_date VARCHAR2(15),
manager_type VARCHAR2(15),
obj_name VARCHAR2(15),
obj_type VARCHAR2(15)
);
--創建觸發器
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;
/
--測試語句
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;
--相關數據字典-----------------------------------------------------//
SELECT * FROM USER_TRIGGERS;
SELECT * FROM ALL_TRIGGERS;
SELECT * FROM DBA_TRIGGERS; --必須以DBA身份登陸才能使用此數據字典
--啟用和禁用
ALTER TRIGGER trigger_name DISABLE;
ALTER TRIGGER trigger_name ENABLE;
------------------------------------------------------------------------------------------End//