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上一篇對觸發器的一些基本知識有了了解，在這一篇操作進行驗證
before觸發器
[oracle@test ~]$ sqlplus / as sysdba
SQL> create user trigger_test identified by 123456 ; SQL> grant create session to trigger_test ; SQL> grant create table to trigger_test ; SQL> grant dba to trigger_test ; SQL> grant resource to trigger_test ； SQL> grant create sequence to trigger_test ;
[oracle@test ~]$ sqlplus trigger_test/123456
創建測試表student
SQL> create table student(STUDENT_ID NUMBER(8),name varchar2(15),CREATED_BY VARCHAR2(30) not null,CREATED_DATE DATE not null,MODIFIED_BY VARCHAR2(30) not null,MODIFIED_DATE DATE not null)
創建序列student_id_seq
create sequence student_id_seq minvalue 1 maxvalue 9999999999999999999999999999 start with 100 increment by 1;
SQL> select * from student ; no rows selected SQL> select * from cat ; TABLE_NAME TABLE_TYPE ------------------------------ ----------- STUDENT TABLE STUDENT_ID_SEQ SEQUENCE
create or replace trigger student_before_insert before insert on student for each row declare v_student_id student.student_id%type ; begin select student_id_seq.nextval into v_student_id from dual ; :new.student_id := v_student_id ; :new.created_by := user ; :new.created_date := sysdate ; :new.modified_by := user ; :new.modified_date := sysdate ; end;
SQL> insert into student (name) values ('mjt');
SQL> commit ;
SQL> select * from student ;
STUDENT_ID NAME CREATED_BY CREATED_DATE
---------- --------------- ------------------------------ -------------------
MODIFIED_BY MODIFIED_DATE
------------------------------ -------------------
100 mjt TRIGGER_TEST 2015-07-29 20:51:19
TRIGGER_TEST 2015-07-29 20:51:19
SQL> insert into student (name) values ('cxq') ;
1 row created.
SQL> select * from student ;
STUDENT_ID NAME CREATED_BY CREATED_DATE
---------- --------------- ------------------------------ -------------------
MODIFIED_BY MODIFIED_DATE
------------------------------ -------------------
100 mjt TRIGGER_TEST 2015-07-29 20:51:19
TRIGGER_TEST 2015-07-29 20:51:19
101 cxq TRIGGER_TEST 2015-07-29 21:00:54
TRIGGER_TEST 2015-07-29 21:00:54after觸發器
SQL> create table record(table_name varchar2(30),transaction_name varchar2(10),transaction_user varchar2(30),transaction_date date);
這個表被用來記錄數據庫中不同表的信息，如，可以記錄誰從student表中刪除或者更新數據，以及記錄時間。
下面的觸發器針對對student表的更新或者刪除操作，在此之后進行觸發
create or replace trigger student_aud
after update or delete on student
declare
v_type varchar2(10);
begin
if updating then
v_type := 'UPDATE';
elsif deleting then
v_type := 'DELETE';
end if;
update trigger_test.record
set transaction_user = user,
transaction_date = sysdate
where table_name = 'student'
and transaction_name = v_type;
if sql%notfound then
insert into trigger_test.record values ('student', v_type, user, sysdate);
end if;
end;SQL> select * from record ; no rows selected SQL> select * from student ; STUDENT_ID NAME CREATED_BY CREATED_DATE ---------- --------------- ------------------------------ ------------------- MODIFIED_BY MODIFIED_DATE ------------------------------ ------------------- 100 mjt TRIGGER_TEST 2015-07-29 20:51:19 TRIGGER_TEST 2015-07-29 20:51:19 101 cxq TRIGGER_TEST 2015-07-29 21:00:54 TRIGGER_TEST 2015-07-29 21:00:54 SQL> update student set name = 'somebody' where name = 'mjt' ; 1 row updated. SQL> commit ; Commit complete. SQL> select * from student ; STUDENT_ID NAME CREATED_BY CREATED_DATE ---------- --------------- ------------------------------ ------------------- MODIFIED_BY MODIFIED_DATE ------------------------------ ------------------- 100 somebody TRIGGER_TEST 2015-07-29 20:51:19 TRIGGER_TEST 2015-07-29 20:51:19 101 cxq TRIGGER_TEST 2015-07-29 21:00:54 TRIGGER_TEST 2015-07-29 21:00:54 SQL> select * from record ; TABLE_NAME TRANSACTIO TRANSACTION_USER ------------------------------ ---------- ------------------------------ TRANSACTION_DATE ------------------- student UPDATE TRIGGER_TEST 2015-07-29 21:50:46 SQL> delete student where name = 'somebody' ; 1 row deleted. SQL> commit ; Commit complete. SQL> select * from student ; STUDENT_ID NAME CREATED_BY CREATED_DATE ---------- --------------- ------------------------------ ------------------- MODIFIED_BY MODIFIED_DATE ------------------------------ ------------------- 101 cxq TRIGGER_TEST 2015-07-29 21:00:54 TRIGGER_TEST 2015-07-29 21:00:54 SQL> select * from record ; TABLE_NAME TRANSACTIO TRANSACTION_USER ------------------------------ ---------- ------------------------------ TRANSACTION_DATE ------------------- student UPDATE TRIGGER_TEST 2015-07-29 21:50:46 student DELETE TRIGGER_TEST 2015-07-29 21:56:08 SQL> alter trigger student_aud disable ; Trigger altered. SQL> update student set name = 'mjt' where name = 'cxq'; 1 row updated. SQL> commit ; Commit complete. SQL> select * from student ; STUDENT_ID NAME CREATED_BY CREATED_DATE ---------- --------------- ------------------------------ ------------------- MODIFIED_BY MODIFIED_DATE ------------------------------ ------------------- 101 mjt TRIGGER_TEST 2015-07-29 21:00:54 TRIGGER_TEST 2015-07-29 21:00:54 SQL> select * from record ; TABLE_NAME TRANSACTIO TRANSACTION_USER ------------------------------ ---------- ------------------------------ TRANSACTION_DATE ------------------- student UPDATE TRIGGER_TEST 2015-07-29 21:50:46 student DELETE TRIGGER_TEST 2015-07-29 21:56:08
禁用觸發器之后，在student表上的update操作不再觸發產生記錄到record表
對應啟用
SQL> alter trigger student_aud enable ; Trigger altered.
3.自治事務
自治事務是由其他事務(通常被稱為主事務)發起的獨立事務，自治事務也許會執行多個dml語句，并且提交或者回滾，而不會提交或者回滾主事務執行的dml語句。
假如希望即使主事務失敗，仍舊能夠記錄審計數據，這種情況下，主事務是面向
表的update或者delete，需要定義可以獨立于主事務進行提交的自治事務。
定義主事務，需要使用autonomous_transaction編譯指令在語句塊的聲明部分
declare
pragma autonomous_transaction
commit ;
create or replace trigger student_aud
after update or delete on student
declare
v_type varchar2(10);
pragma autonomous_transaction ;
begin
if updating then
v_type := 'UPDATE';
elsif deleting then
v_type := 'DELETE';
end if;
update trigger_test.record
set transaction_user = user,
transaction_date = sysdate
where table_name = 'student'
and transaction_name = v_type;
if sql%notfound then
insert into trigger_test.record values ('student', v_type, user, sysdate);
end if;
commit ;
end;如果當前更新或者刪除表student中的內容，無論成功或者失敗，都會在record表中記錄當前的操作。不足的是，record表中最多只能記錄兩條數據，只是當前最新操作的時間以及操作者。
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