ORACLE 触发器

?1.1 触发器类型
?1.1.1 DML触发器
?1.1.2 替代触发器
?1.1.3 系统触发器
?1.2 创建触发器
?1.2.1 触发器触发次序
?1.2.2 创建DML触发器
?1.2.3 创建替代(INSTEAD OF)触发器
?1.2.3 创建系统事件触发器
?1.2.4 系统触发器事件属性
?1.2.5 使用触发器谓词
?1.2.6 重新编译触发器
?1.3 删除和使能触发器
?1.4 触发器和数据字典
?1.5 数据库触发器的应用举例

1 CREATE [OR REPLACE] TRIGGER trigger_name
2 {BEFORE | AFTER }
3 {INSERT | DELETE | UPDATE [OF column [, column …]]}
4 [OR {INSERT | DELETE | UPDATE [OF column [, column …]]}...]
5 ON [schema.]table_name | [schema.]view_name 
6 [REFERENCING {OLD [AS] old | NEW [AS] new| PARENT as parent}]
7 [FOR EACH ROW ]
8 [WHEN condition]
9 PL/SQL_BLOCK | CALL procedure_name;

BEFORE INSERT
BEFORE INSERT FOR EACH ROW
AFTER INSERT
AFTER INSERT FOR EACH ROW
 
BEFORE UPDATE
BEFORE UPDATE FOR EACH ROW
AFTER UPDATE
AFTER UPDATE FOR EACH ROW
 
BEFORE DELETE
BEFORE DELETE FOR EACH ROW
AFTER DELETE
AFTER DELETE FOR EACH ROW

 1 CREATE TABLE emp_his AS SELECT * FROM EMP WHERE 1=2; 
 2 CREATE OR REPLACE TRIGGER tr_del_emp 
 3    BEFORE DELETE --指定触发时机为删除操作前触发
 4    ON scott.emp 
 5    FOR EACH ROW   --说明创建的是行级触发器 
 6 BEGIN
 7    --将修改前数据插入到日志记录表 del_emp ,以供监督使用。
 8    INSERT INTO emp_his(deptno , empno, ename , job ,mgr , sal , comm , hiredate )
 9        VALUES( :old.deptno, :old.empno, :old.ename , :old.job,:old.mgr, :old.sal, :old.comm, :old.hiredate );
10 END;
11 DELETE emp WHERE empno=7788;
12 DROP TABLE emp_his;
13 DROP TRIGGER del_emp;

1 CREATE OR REPLACE TRIGGER tr_dept_time
2 BEFORE INSERT OR DELETE OR UPDATE 
3 ON departments
4 BEGIN
5  IF (TO_CHAR(sysdate,‘DAY‘) IN (‘星期六‘, ‘星期日‘)) OR (TO_CHAR(sysdate, ‘HH24:MI‘) NOT BETWEEN ‘08:30‘ AND ‘18:00‘) THEN
6      RAISE_APPLICATION_ERROR(-20001, ‘不是上班时间，不能修改departments表‘);
7  END IF;
8 END;

 1 CREATE OR REPLACE TRIGGER tr_emp_sal_comm
 2 BEFORE UPDATE OF salary, commission_pct
 3        OR DELETE
 4 ON HR.employees
 5 FOR EACH ROW
 6 WHEN (old.department_id = 80)
 7 BEGIN
 8  CASE
 9      WHEN UPDATING (‘salary‘) THEN
10         IF :NEW.salary < :old.salary THEN
11 
12            RAISE_APPLICATION_ERROR(-20001, ‘部门80的人员的工资不能降‘);
13         END IF;
14      WHEN UPDATING (‘commission_pct‘) THEN
15 
16         IF :NEW.commission_pct < :old.commission_pct THEN
17            RAISE_APPLICATION_ERROR(-20002, ‘部门80的人员的奖金不能降‘);
18         END IF;
19      WHEN DELETING THEN
20           RAISE_APPLICATION_ERROR(-20003, ‘不能删除部门80的人员记录‘);
21      END CASE;
22 END; 

 1 CREATE OR REPLACE TRIGGER tr_reg_cou
 2 AFTER update OF region_id
 3 ON regions
 4 FOR EACH ROW
 5 BEGIN
 6  DBMS_OUTPUT.PUT_LINE(‘旧的region_id值是‘||:old.region_id
 7                   ||‘、新的region_id值是‘||:new.region_id);
 8  UPDATE countries SET region_id = :new.region_id
 9  WHERE region_id = :old.region_id;
10 END;

 1 CREATE OR REPLACE PROCEDURE add_job_history
 2  ( p_emp_id          job_history.employee_id%type
 3    , p_start_date      job_history.start_date%type
 4   , p_end_date        job_history.end_date%type
 5    , p_job_id          job_history.job_id%type
 6    , p_department_id   job_history.department_id%type
 7    )
 8 IS
 9 BEGIN
10  INSERT INTO job_history (employee_id, start_date, end_date,
11                            job_id, department_id)
12   VALUES(p_emp_id, p_start_date, p_end_date, p_job_id, p_department_id);
13 END add_job_history;

1 --创建触发器调用存储过程...
2 CREATE OR REPLACE TRIGGER update_job_history
3  AFTER UPDATE OF job_id, department_id ON employees
4  FOR EACH ROW
5 BEGIN
6  add_job_history(:old.employee_id, :old.hire_date, sysdate,
7                   :old.job_id, :old.department_id);
8 END;

1 CREATE [OR REPLACE] TRIGGER trigger_name
2 INSTEAD OF
3 {INSERT | DELETE | UPDATE [OF column [, column …]]}
4 [OR {INSERT | DELETE | UPDATE [OF column [, column …]]}...]
5 ON [schema.] view_name --只能定义在视图上
6 [REFERENCING {OLD [AS] old | NEW [AS] new| PARENT as parent}]
7 [FOR EACH ROW ] --因为INSTEAD OF触发器只能在行级上触发,所以没有必要指定
8 [WHEN condition]
9 PL/SQL_block | CALL procedure_name;

1 CREATE OR REPLACE VIEW emp_view AS 
2 SELECT deptno, count(*) total_employeer, sum(sal) total_salary 
3 FROM emp GROUP BY deptno;

1 SQL>DELETE FROM emp_view WHERE deptno=10;
2 DELETE FROM emp_view WHERE deptno=10

 1 CREATE OR REPLACE TRIGGER emp_view_delete
 2    INSTEAD OF DELETE ON emp_view FOR EACH ROW
 3 BEGIN
 4    DELETE FROM emp WHERE deptno= :old.deptno;
 5 END emp_view_delete; 
 6 
 7 DELETE FROM emp_view WHERE deptno=10; 
 8 
 9 DROP TRIGGER emp_view_delete;
10 
11 DROP VIEW emp_view; 

1 CREATE OR REPLACE FORCE VIEW "HR"."V_REG_COU" ("R_ID", "R_NAME", "C_ID", "C_NAME")
2 AS
3  SELECT r.region_id,
4     r.region_name,
5     c.country_id,
6     c.country_name
7  FROM regions r,
8     countries c
9  WHERE r.region_id = c.region_id;

 1 CREATE OR REPLACE TRIGGER "HR"."TR_I_O_REG_COU" INSTEAD OF
 2  INSERT ON v_reg_cou FOR EACH ROW DECLARE v_count NUMBER;
 3 BEGIN
 4  SELECT COUNT(*) INTO v_count FROM regions WHERE region_id = :new.r_id;
 5  IF v_count = 0 THEN
 6     INSERT INTO regions
 7       (region_id, region_name
 8       ) VALUES
 9       (:new.r_id, :new.r_name
10       );
11  END IF;
12 
13  SELECT COUNT(*) INTO v_count FROM countries WHERE country_id = :new.c_id;
14  IF v_count = 0 THEN
15     INSERT
16     INTO countries
17       (
18         country_id,
19         country_name,
20         region_id
21       )
22       VALUES
23       (
24         :new.c_id,
25         :new.c_name,
26         :new.r_id
27       );
28  END IF;
29 END;

CREATE OR REPLACE TRIGGER [sachema.]trigger_name
{BEFORE|AFTER} 
{ddl_event_list | database_event_list}
ON { DATABASE | [schema.]SCHEMA }
[WHEN condition]
PL/SQL_block | CALL procedure_name;

 1 DESC ora_sysevent
 2 DESC ora_login_user
 3 
 4 --创建用于记录事件用的表
 5 
 6 CREATE TABLE ddl_event
 7 (crt_date timestamp PRIMARY KEY,
 8  event_name VARCHAR2(20), 
 9  user_name VARCHAR2(10),
10  obj_type VARCHAR2(20),
11  obj_name VARCHAR2(20));
12 
13 --创建触犯发器
14 CREATE OR REPLACE TRIGGER tr_ddl
15 AFTER DDL ON SCHEMA
16 BEGIN
17    INSERT INTO ddl_event VALUES
18    (systimestamp,ora_sysevent, ora_login_user, 
19     ora_dict_obj_type, ora_dict_obj_name);
20 END tr_ddl;

 1 CREATE TABLE log_event
 2 (user_name VARCHAR2(10),
 3  address VARCHAR2(20), 
 4  logon_date timestamp,
 5  logoff_date timestamp); 
 6 
 7 --创建登录触发器
 8 CREATE OR REPLACE TRIGGER tr_logon
 9 AFTER LOGON ON DATABASE
10 BEGIN
11    INSERT INTO log_event (user_name, address, logon_date)
12    VALUES (ora_login_user, ora_client_ip_address, systimestamp);
13 END tr_logon;
14 --创建退出触发器
15 CREATE OR REPLACE TRIGGER tr_logoff
16 BEFORE LOGOFF ON DATABASE
17 BEGIN
18    INSERT INTO log_event (user_name, address, logoff_date)
19    VALUES (ora_login_user, ora_client_ip_address, systimestamp);
20 END tr_logoff;
21  

ALTER TRIGGER [schema.] trigger_name COMPILE [ DEBUG]

DROP TRIGGER trigger_name;

ALTER TIGGER trigger_name [DISABLE | ENABLE ];

ALTER TABLE [schema.]table_name {ENABLE|DISABLE} ALL TRIGGERS;

--例：使表EMP 上的所有TRIGGER 失效：
ALTER TABLE emp DISABLE ALL TRIGGERS; 

USER_TRIGGERS、ALL_TRIGGERS、DBA_TRIGGERS 
SELECT TRIGGER_NAME, TRIGGER_TYPE, TRIGGERING_EVENT,
 TABLE_OWNER, BASE_OBJECT_TYPE, REFERENCING_NAMES,
 STATUS, ACTION_TYPE
 FROM user_triggers;

 1 CREATE TABLE dept_summary(
 2  Deptno NUMBER(2),
 3  Sal_sum NUMBER(9, 2),
 4  Emp_count NUMBER); 
 5 
 6 INSERT INTO dept_summary(deptno, sal_sum, emp_count)
 7  SELECT deptno, SUM(sal), COUNT(*) 
 8 FROM emp 
 9 GROUP BY deptno;
10 
11 --创建一个PL/SQL过程disp_dept_summary
12 --在触发器中调用该过程显示dept_summary标中的数据。
13 CREATE OR REPLACE PROCEDURE disp_dept_summary
14 IS
15  Rec dept_summary%ROWTYPE;
16  CURSOR c1 IS SELECT * FROM dept_summary;
17 BEGIN
18  OPEN c1;
19  FETCH c1 INTO REC;
20  DBMS_OUTPUT.PUT_LINE(‘deptno    sal_sum    emp_count‘);
21  DBMS_OUTPUT.PUT_LINE(‘-------------------------------------‘);
22  WHILE c1%FOUND LOOP
23     DBMS_OUTPUT.PUT_LINE(RPAD(rec.deptno, 6)||
24       To_char(rec.sal_sum, ‘$999,999.99‘)||
25       LPAD(rec.emp_count, 13));
26     FETCH c1 INTO rec;
27  END LOOP;
28  CLOSE c1;
29 END;
30 BEGIN
31  DBMS_OUTPUT.PUT_LINE(‘插入前‘);
32  Disp_dept_summary();
33  DBMS_UTILITY.EXEC_DDL_STATEMENT(‘
34     CREATE OR REPLACE TRIGGER trig1
35       AFTER INSERT OR DELETE OR UPDATE OF sal ON emp
36     BEGIN
37       DBMS_OUTPUT.PUT_LINE(‘‘正在执行trig1 触发器…‘‘);
38       DELETE FROM dept_summary;
39       INSERT INTO dept_summary(deptno, sal_sum, emp_count)
40       SELECT deptno, SUM(sal), COUNT(*) 
41       FROM emp GROUP BY deptno;
42     END;
43  ‘);
44 
45 
46  INSERT INTO dept(deptno, dname, loc) 
47  VALUES(90, ‘demo_dept’, ‘none_loc’);
48  INSERT INTO emp(ename, deptno, empno, sal)
49  VALUES(USER, 90, 9999, 3000);
50 
51  DBMS_OUTPUT.PUT_LINE(‘插入后‘);
52  Disp_dept_summary();
53 
54  UPDATE emp SET sal=1000 WHERE empno=9999;
55  DBMS_OUTPUT.PUT_LINE(‘修改后‘);
56  Disp_dept_summary();
57 
58  DELETE FROM emp WHERE empno=9999;
59  DELETE FROM dept WHERE deptno=90;
60 
61  DBMS_OUTPUT.PUT_LINE(‘删除后‘);
62  Disp_dept_summary(); 
63  DBMS_UTILITY.EXEC_DDL_STATEMENT(‘DROP TRIGGER trig1’);
64 EXCEPTION
65    WHEN OTHERS THEN
66       DBMS_OUTPUT.PUT_LINE(SQLCODE||‘---‘||SQLERRM);
67 
68 END;
69  

 1 BEGIN
 2   DBMS_OUTPUT.PUT_LINE(‘插入前‘);
 3   Disp_dept_summary();
 4   DBMS_UTILITY.EXEC_DDL_STATEMENT(
 5     ‘CREATE OR REPLACE TRIGGER trig2_update
 6       AFTER UPDATE OF sal ON emp
 7       REFERENCING OLD AS old_emp NEW AS new_emp
 8       FOR EACH ROW
 9       WHEN (old_emp.sal != new_emp.sal)
10     BEGIN
11       DBMS_OUTPUT.PUT_LINE(‘‘正在执行trig2_update 触发器…‘‘);
12       DBMS_OUTPUT.PUT_LINE(‘‘sal 旧值：‘‘|| :old_emp.sal);
13       DBMS_OUTPUT.PUT_LINE(‘‘sal 新值：‘‘|| :new_emp.sal);
14       UPDATE dept_summary
15         SET sal_sum=sal_sum + :new_emp.sal - :old_emp.sal
16         WHERE deptno = :new_emp.deptno;
17     END;‘
18   );
19   
20   DBMS_UTILITY.EXEC_DDL_STATEMENT(
21     ‘CREATE OR REPLACE TRIGGER trig2_insert
22       AFTER INSERT ON emp
23       REFERENCING NEW AS new_emp
24       FOR EACH ROW
25     DECLARE
26       I NUMBER;
27     BEGIN
28       DBMS_OUTPUT.PUT_LINE(‘‘正在执行trig2_insert 触发器…‘‘);
29       SELECT COUNT(*) INTO I 
30       FROM dept_summary WHERE deptno = :new_emp.deptno;
31       IF I > 0 THEN
32         UPDATE dept_summary 
33         SET sal_sum=sal_sum+:new_emp.sal,
34         Emp_count=emp_count+1
35         WHERE deptno = :new_emp.deptno;
36       ELSE
37         INSERT INTO dept_summary
38         VALUES (:new_emp.deptno, :new_emp.sal, 1);
39       END IF;
40     END;‘
41   );
42 
43   DBMS_UTILITY.EXEC_DDL_STATEMENT(
44     ‘CREATE OR REPLACE TRIGGER trig2_delete
45       AFTER DELETE ON emp
46       REFERENCING OLD AS old_emp
47       FOR EACH ROW
48     DECLARE
49       I NUMBER;
50     BEGIN
51       DBMS_OUTPUT.PUT_LINE(‘‘正在执行trig2_delete 触发器…‘‘);
52       SELECT emp_count INTO I 
53       FROM dept_summary WHERE deptno = :old_emp.deptno;
54       IF I >1 THEN
55         UPDATE dept_summary 
56         SET sal_sum=sal_sum - :old_emp.sal,
57         Emp_count=emp_count - 1
58         WHERE deptno = :old_emp.deptno;
59       ELSE
60         DELETE FROM dept_summary WHERE deptno = :old_emp.deptno;
61       END IF;
62     END;‘
63   );
64 
65   INSERT INTO dept(deptno, dname, loc) 
66     VALUES(90, ‘demo_dept‘, ‘none_loc‘);
67   INSERT INTO emp(ename, deptno, empno, sal)
68     VALUES(USER, 90, 9999, 3000);
69   INSERT INTO emp(ename, deptno, empno, sal)
70     VALUES(USER, 90, 9998, 2000);
71   DBMS_OUTPUT.PUT_LINE(‘插入后‘);
72   Disp_dept_summary();
73 
74   UPDATE emp SET sal = sal*1.1 WHERE deptno=90;
75   DBMS_OUTPUT.PUT_LINE(‘修改后‘);
76   Disp_dept_summary();
77 
78   DELETE FROM emp WHERE deptno=90;
79   DELETE FROM dept WHERE deptno=90;
80   DBMS_OUTPUT.PUT_LINE(‘删除后‘);
81   Disp_dept_summary();
82 
83   DBMS_UTILITY.EXEC_DDL_STATEMENT(‘DROP TRIGGER trig2_update‘);
84   DBMS_UTILITY.EXEC_DDL_STATEMENT(‘DROP TRIGGER trig2_insert‘);
85   DBMS_UTILITY.EXEC_DDL_STATEMENT(‘DROP TRIGGER trig2_delete‘);
86 EXCEPTION
87    WHEN OTHERS THEN
88       DBMS_OUTPUT.PUT_LINE(SQLCODE||‘---‘||SQLERRM);
89 END;

 1 BEGIN
 2     DBMS_OUTPUT.PUT_LINE(‘插入前‘);
 3     Disp_dept_summary();
 4     DBMS_UTILITY.EXEC_DDL_STATEMENT(
 5         ‘CREATE OR REPLACE TRIGGER trig2
 6             AFTER INSERT OR DELETE OR UPDATE OF sal
 7 ON emp
 8             REFERENCING OLD AS old_emp NEW AS new_emp
 9             FOR EACH ROW
10         DECLARE
11             I NUMBER;
12         BEGIN
13             IF UPDATING AND :old_emp.sal != :new_emp.sal THEN
14             DBMS_OUTPUT.PUT_LINE(‘‘正在执行trig2 触发器…‘‘);
15                 DBMS_OUTPUT.PUT_LINE(‘‘sal 旧值：‘‘|| :old_emp.sal);
16                 DBMS_OUTPUT.PUT_LINE(‘‘sal 新值：‘‘|| :new_emp.sal);
17                 UPDATE dept_summary
18                     SET sal_sum=sal_sum + :new_emp.sal - :old_emp.sal
19                 WHERE deptno = :new_emp.deptno;
20             ELSIF INSERTING THEN
21                 DBMS_OUTPUT.PUT_LINE(‘‘正在执行trig2触发器…‘‘);
22                 SELECT COUNT(*) INTO I 
23         FROM dept_summary 
24         WHERE deptno = :new_emp.deptno;
25                 IF I > 0 THEN
26                     UPDATE dept_summary 
27           SET sal_sum=sal_sum+:new_emp.sal,
28               Emp_count=emp_count+1
29           WHERE deptno = :new_emp.deptno;
30             ELSE
31           INSERT INTO dept_summary
32             VALUES (:new_emp.deptno, :new_emp.sal, 1);
33         END IF;
34       ELSE
35         DBMS_OUTPUT.PUT_LINE(‘‘正在执行trig2触发器…‘‘);
36         SELECT emp_count INTO I 
37         FROM dept_summary WHERE deptno = :old_emp.deptno;
38       IF I > 1 THEN
39         UPDATE dept_summary 
40         SET sal_sum=sal_sum - :old_emp.sal,
41         Emp_count=emp_count - 1
42         WHERE deptno = :old_emp.deptno;
43       ELSE
44           DELETE FROM dept_summary 
45           WHERE deptno = :old_emp.deptno;
46       END IF;
47     END IF;
48     END;‘
49   );
50 
51   INSERT INTO dept(deptno, dname, loc) 
52     VALUES(90, ‘demo_dept‘, ‘none_loc‘);
53   INSERT INTO emp(ename, deptno, empno, sal)
54     VALUES(USER, 90, 9999, 3000);
55   INSERT INTO emp(ename, deptno, empno, sal)
56     VALUES(USER, 90, 9998, 2000);
57   DBMS_OUTPUT.PUT_LINE(‘插入后‘);
58   Disp_dept_summary();
59 
60   UPDATE emp SET sal = sal*1.1 WHERE deptno=90;
61   DBMS_OUTPUT.PUT_LINE(‘修改后‘);
62   Disp_dept_summary();
63 
64   DELETE FROM emp WHERE deptno=90;
65   DELETE FROM dept WHERE deptno=90;
66   DBMS_OUTPUT.PUT_LINE(‘删除后‘);
67   Disp_dept_summary();
68 
69   DBMS_UTILITY.EXEC_DDL_STATEMENT(‘DROP TRIGGER trig2‘);
70 EXCEPTION
71    WHEN OTHERS THEN
72       DBMS_OUTPUT.PUT_LINE(SQLCODE||‘---‘||SQLERRM);
73 END;

 1 DECLARE
 2     No NUMBER;
 3     Name VARCHAR2(20);
 4 BEGIN
 5     DBMS_UTILITY.EXEC_DDL_STATEMENT(‘
 6         CREATE OR REPLACE VIEW myview AS
 7             SELECT empno, ename, ‘‘E‘‘ type FROM emp
 8             UNION
 9             SELECT dept.deptno, dname, ‘‘D‘‘ FROM dept
10     ‘);
11     -- 创建INSTEAD OF 触发器trigger3;
12     DBMS_UTILITY.EXEC_DDL_STATEMENT(‘
13         CREATE OR REPLACE TRIGGER trig3
14             INSTEAD OF INSERT ON myview
15             REFERENCING NEW n
16             FOR EACH ROW
17         DECLARE
18             Rows INTEGER;
19         BEGIN
20             DBMS_OUTPUT.PUT_LINE(‘‘正在执行trig3触发器…‘‘);
21             IF :n.type = ‘‘D‘‘ THEN
22                 SELECT COUNT(*) INTO rows
23                     FROM dept WHERE deptno = :n.empno;
24                 IF rows = 0 THEN
25                     DBMS_OUTPUT.PUT_LINE(‘‘向dept表中插入数据…‘‘);
26                     INSERT INTO dept(deptno, dname, loc)
27                         VALUES (:n.empno, :n.ename, ‘‘none’’);
28                 ELSE
29                     DBMS_OUTPUT.PUT_LINE(‘‘编号为‘‘|| :n.empno||
30                      ‘‘的部门已存在，插入操作失败！‘‘);
31                  END IF;
32             ELSE
33                 SELECT COUNT(*) INTO rows
34                     FROM emp WHERE empno = :n.empno;
35                 IF rows = 0 THEN
36                     DBMS_OUTPUT.PUT_LINE(‘’向emp表中插入数据…’’);
37                     INSERT INTO emp(empno, ename)
38                         VALUES(:n.empno, :n.ename);
39                 ELSE
40                     DBMS_OUTPUT.PUT_LINE(‘‘编号为‘‘|| :n.empno||
41                       ‘‘的人员已存在，插入操作失败!‘‘);
42                 END IF;
43             END IF;
44         END;
45     ‘);
46 
47     INSERT INTO myview VALUES (70, ‘demo‘, ‘D‘);
48     INSERT INTO myview VALUES (9999, USER, ‘E‘);
49     SELECT deptno, dname INTO no, name FROM dept WHERE deptno=70;
50     DBMS_OUTPUT.PUT_LINE(‘员工编号：‘||TO_CHAR(no)||‘姓名：‘||name);
51     SELECT empno, ename INTO no, name FROM emp WHERE empno=9999;
52     DBMS_OUTPUT.PUT_LINE(‘部门编号：‘||TO_CHAR(no)||‘姓名：‘||name);
53   DELETE FROM emp WHERE empno=9999;
54   DELETE FROM dept WHERE deptno=70;
55     DBMS_UTILITY.EXEC_DDL_STATEMENT(‘DROP TRIGGER trig3‘);
56 END;

  1 BEGIN
  2     -- 创建用于记录事件日志的数据表
  3     DBMS_UTILITY.EXEC_DDL_STATEMENT(‘
  4         CREATE TABLE eventlog(
  5             Eventname VARCHAR2(20) NOT NULL,
  6             Eventdate date default sysdate,
  7             Inst_num NUMBER NULL,
  8             Db_name VARCHAR2(50) NULL,
  9             Srv_error NUMBER NULL,
 10             Username VARCHAR2(30) NULL,
 11             Obj_type VARCHAR2(20) NULL,
 12             Obj_name VARCHAR2(30) NULL,
 13             Obj_owner VARCHAR2(30) NULL
 14         )
 15     ‘);
 16 
 17     -- 创建DDL触发器trig4_ddl
 18     DBMS_UTILITY.EXEC_DDL_STATEMENT(‘
 19         CREATE OR REPLACE TRIGGER trig4_ddl
 20             AFTER CREATE OR ALTER OR DROP 
 21 ON DATABASE
 22         DECLARE
 23             Event VARCHAR2(20);
 24             Typ VARCHAR2(20);
 25             Name VARCHAR2(30);
 26             Owner VARCHAR2(30);
 27         BEGIN
 28             -- 读取DDL事件属性
 29             Event := SYSEVENT;
 30             Typ := DICTIONARY_OBJ_TYPE;
 31             Name := DICTIONARY_OBJ_NAME;
 32             Owner := DICTIONARY_OBJ_OWNER;
 33             --将事件属性插入到事件日志表中
 34             INSERT INTO scott.eventlog(eventname, obj_type, obj_name, obj_owner)
 35                 VALUES(event, typ, name, owner);
 36         END;
 37     ‘);
 38 
 39     -- 创建LOGON、STARTUP和SERVERERROR 事件触发器
 40     DBMS_UTILITY.EXEC_DDL_STATEMENT(‘
 41         CREATE OR REPLACE TRIGGER trig4_after
 42             AFTER LOGON OR STARTUP OR SERVERERROR 
 43       ON DATABASE
 44         DECLARE
 45             Event VARCHAR2(20);
 46             Instance NUMBER;
 47             Err_num NUMBER;
 48             Dbname VARCHAR2(50);
 49             User VARCHAR2(30);
 50         BEGIN
 51             Event := SYSEVENT;
 52             IF event = ‘‘LOGON‘‘ THEN
 53                 User := LOGIN_USER;
 54                 INSERT INTO eventlog(eventname, username)
 55                     VALUES(event, user);
 56             ELSIF event = ‘‘SERVERERROR‘‘ THEN
 57                 Err_num := SERVER_ERROR(1);
 58                 INSERT INTO eventlog(eventname, srv_error)
 59                     VALUES(event, err_num);
 60             ELSE
 61                 Instance := INSTANCE_NUM;
 62                 Dbname := DATABASE_NAME;
 63                 INSERT INTO eventlog(eventname, inst_num, db_name)
 64                     VALUES(event, instance, dbname);
 65       END IF;
 66     END;
 67   ‘);
 68 
 69   -- 创建LOGOFF和SHUTDOWN 事件触发器
 70   DBMS_UTILITY.EXEC_DDL_STATEMENT(‘
 71     CREATE OR REPLACE TRIGGER trig4_before
 72       BEFORE LOGOFF OR SHUTDOWN 
 73       ON DATABASE
 74     DECLARE
 75       Event VARCHAR2(20);
 76       Instance NUMBER;
 77       Dbname VARCHAR2(50);
 78       User VARCHAR2(30);
 79     BEGIN
 80       Event := SYSEVENT;
 81       IF event = ‘‘LOGOFF‘‘ THEN
 82         User := LOGIN_USER;
 83         INSERT INTO eventlog(eventname, username)
 84           VALUES(event, user);
 85       ELSE
 86         Instance := INSTANCE_NUM;
 87         Dbname := DATABASE_NAME;
 88         INSERT INTO eventlog(eventname, inst_num, db_name)
 89           VALUES(event, instance, dbname);
 90       END IF;
 91     END;
 92   ‘);
 93 END;
 94 
 95 CREATE TABLE mydata(mydate NUMBER);
 96 CONNECT SCOTT/TIGER
 97 
 98 COL eventname FORMAT A10
 99 COL eventdate FORMAT A12
100 COL username FORMAT A10
101 COL obj_type FORMAT A15
102 COL obj_name FORMAT A15
103 COL obj_owner FORMAT A10
104 SELECT eventname, eventdate, obj_type, obj_name, obj_owner, username, Srv_error
105   FROM eventlog;
106 
107 DROP TRIGGER trig4_ddl;
108 DROP TRIGGER trig4_before;
109 DROP TRIGGER trig4_after;
110 DROP TABLE eventlog;
111 DROP TABLE mydata;

 1 Audit_id     NUMBER,
 2     User_name VARCHAR2(20),
 3     Now_time DATE,
 4     Terminal_name VARCHAR2(10),
 5     Table_name VARCHAR2(10),
 6     Action_name VARCHAR2(10),
 7     Emp_id NUMBER(4));
 8 
 9 CREATE TABLE audit_table_val(
10     Audit_id NUMBER,
11     Column_name VARCHAR2(10),
12     Old_val NUMBER(7,2),
13     New_val NUMBER(7,2));
14 
15 CREATE SEQUENCE audit_seq
16     START WITH 1000
17     INCREMENT BY 1
18     NOMAXVALUE
19     NOCYCLE NOCACHE;
20 
21 CREATE OR REPLACE TRIGGER audit_emp
22     AFTER INSERT OR UPDATE OR DELETE ON emp
23     FOR EACH ROW
24 DECLARE
25     Time_now DATE;
26     Terminal CHAR(10);
27 BEGIN 
28     Time_now:=sysdate;
29     Terminal:=USERENV(‘TERMINAL‘);
30     IF INSERTING THEN
31         INSERT INTO audit_table
32     VALUES(audit_seq.NEXTVAL, user, time_now, 
33            terminal, ‘EMP‘, ‘INSERT‘, :new.empno);
34     ELSIF DELETING THEN
35         INSERT INTO audit_table
36     VALUES(audit_seq.NEXTVAL, user, time_now, 
37            terminal, ‘EMP‘, ‘DELETE‘, :old.empno);
38     ELSE
39         INSERT INTO audit_table
40     VALUES(audit_seq.NEXTVAL, user, time_now, 
41            terminal, ‘EMP‘, ‘UPDATE‘, :old.empno);
42         IF UPDATING(‘SAL‘) THEN
43             INSERT INTO audit_table_val
44                 VALUES(audit_seq.CURRVAL, ‘SAL‘, :old.sal, :new.sal);
45         ELSE UPDATING(‘DEPTNO‘) 
46             INSERT INTO audit_table_val
47                 VALUES(audit_seq.CURRVAL, ‘DEPTNO‘, :old.deptno, :new.deptno);
48         END IF;
49     END IF;
50 END;

 1 CREATE SEQUENCE update_sequence 
 2     INCREMENT BY 1
 3     START WITH 1000
 4     MAXVALUE 5000 CYCLE;
 5 
 6 ALTER TABLE emp
 7     ADD update_id NUMBER;
 8 
 9 CREATE OR REPLACE PACKAGE integritypackage AS
10     Updateseq NUMBER;
11 END integritypackage;
12 
13 CREATE OR REPLACE PACKAGE BODY integritypackage AS
14 END integritypackage;
15 
16 CREATE OR REPLACE TRIGGER dept_cascade1
17     BEFORE UPDATE OF deptno ON dept
18 DECLARE 
19     Dummy NUMBER;
20 BEGIN 
21     SELECT update_sequence.NEXTVAL INTO dummy FROM dual;
22     Integritypackage.updateseq:=dummy;
23 END;
24 
25 CREATE OR REPLACE TRIGGER dept_cascade2
26     AFTER DELETE OR UPDATE OF deptno ON dept
27     FOR EACH ROW
28 BEGIN
29     IF UPDATING THEN
30         UPDATE emp SET deptno=:new.deptno, 
31      update_id=integritypackage.updateseq
32         WHERE emp.deptno=:old.deptno AND update_id IS NULL;
33     END IF;
34     IF DELETING THEN
35         DELETE FROM emp
36             WHERE emp.deptno=:old.deptno;
37     END IF;
38 END;
39 
40 CREATE OR REPLACE TRIGGER dept_cascade3
41     AFTER UPDATE OF deptno ON dept 
42 BEGIN
43     UPDATE emp SET update_id=NULL
44         WHERE update_id=integritypackage.updateseq;
45 END;
46 
47 SELECT * FROM EMP ORDER BY DEPTNO;
48 UPDATE dept SET deptno=25 WHERE deptno=20;

 1 CREATE TABLE company_holidays(day DATE);
 2 
 3 INSERT INTO company_holidays 
 4     VALUES(sysdate);
 5 INSERT INTO company_holidays 
 6 VALUES(TO_DATE(‘21-10月-01‘, ‘DD-MON-YY‘));
 7 
 8 CREATE OR REPLACE TRIGGER emp_permit_change
 9     BEFORE INSERT OR DELETE OR UPDATE ON emp
10 DECLARE
11     Dummy NUMBER;
12     Not_on_weekends EXCEPTION;
13     Not_on_holidays EXCEPTION;
14     Not_working_hours EXCEPTION;
15 BEGIN
16     /* check for weekends */
17 IF TO_CHAR(SYSDATE, ‘DAY‘) IN (‘星期六‘, ‘星期日‘) THEN
18     RAISE not_on_weekends;
19 END IF;
20     /* check for company holidays */
21 SELECT COUNT(*) INTO dummy FROM company_holidays
22     WHERE TRUNC(day)=TRUNC(SYSDATE);
23 IF dummy >0 THEN
24     RAISE not_on_holidays;
25 END IF;
26     /* check for work hours(8:00 AM to 18:00 PM */
27 IF (TO_CHAR(SYSDATE,‘HH24‘)<8 OR TO_CHAR(SYSDATE, ‘HH24‘)>18) THEN
28   RAISE not_working_hours;
29 END IF;
30 EXCEPTION
31   WHEN not_on_weekends THEN
32     RAISE_APPLICATION_ERROR(-20324, 
33 ‘May not change employee table during the weekends‘); 
34   WHEN not_on_holidays THEN
35     RAISE_APPLICATION_ERROR(-20325, 
36 ‘May not change employee table during a holiday‘); 
37   WHEN not_working_hours THEN
38     RAISE_APPLICATION_ERROR(-20326, 
39 ‘May not change employee table during no_working hours‘); 
40 END;