eygle.com   eygle.com
eygle.com eygle
eygle.com  
 

« 如何获得跟踪文件名称 | Blog首页 | 我的MT,新的开始 »

使用触发器实现数据库级守护,防止DDL操作

不管是有意还是无意的,你可能会遇到数据库中重要的数据表等对象被drop掉的情况,这可能会给我们带来巨大的损失.

通过触发器,我们可以实现对于表等对象的数据库级守护,禁止用户drop操作.

以下是一个简单的范例,供参考:

REM this script can be used to monitor a object
REM deny any drop operation on it.
CREATE OR REPLACE TRIGGER trg_dropdeny
   BEFORE DROP ON DATABASE
BEGIN
   IF LOWER (ora_dict_obj_name ()) = 'test'
   THEN
      raise_application_error (num      => -20000,
                               msg      =>    '你疯了,想删除表 '
                                           || ora_dict_obj_name ()
                                           || ' ?!!!!!'
                                           || '你完了,警察已在途中.....'
                              );
   END IF;
END;
/       
                      

测试效果:

SQL> connect scott/tiger
Connected.
SQL> create table test as select * from dba_users;

Table created.

SQL> connect / as sysdba
Connected.
SQL> create or replace trigger trg_dropdeny
  2     before drop on database   
  3  begin
  4        if lower(ora_dict_obj_name()) = 'test'        
  5        then
  6        raise_application_error(
  7           num => -20000,
  8           msg => '你疯了,想删除表 ' || ora_dict_obj_name() || ' ?!!!!!' ||'你完了,警察已在途中.....');
  9        end if;
 10     end;
 11  /

Trigger created.

SQL> connect scott/tiger
Connected.
SQL> drop table test;
drop table test
*
ERROR at line 1:
ORA-00604: error occurred at recursive SQL level 1
ORA-20000: 你疯了,想删除表 TEST ?!!!!!你完了,警察已在途中.....
ORA-06512: at line 4
       

Oracle从Oracle8i开始,允许实施DDL事件trigger,可是实现对于DDL的监视及控制,以下是一个进一步的例子:

create or replace trigger ddl_deny
before create or alter or drop or truncate on database
declare
  l_errmsg varchar2(100):= 'You have no permission to this operation';
begin
  if ora_sysevent = 'CREATE' then
     raise_application_error(-20001, ora_dict_obj_owner || '.' || ora_dict_obj_name || ' ' || l_errmsg);
  elsif ora_sysevent = 'ALTER' then
    raise_application_error(-20001, ora_dict_obj_owner || '.' || ora_dict_obj_name || ' ' || l_errmsg);
  elsif ora_sysevent = 'DROP' then
    raise_application_error(-20001, ora_dict_obj_owner || '.' || ora_dict_obj_name || ' ' || l_errmsg);
  elsif ora_sysevent = 'TRUNCATE' then
    raise_application_error(-20001, ora_dict_obj_owner || '.' || ora_dict_obj_name || ' ' || l_errmsg);
  end if;

exception
  when no_data_found then
    null;
end;
/

                      

我们看一下效果:

[oracle@jumper tools]$ sqlplus "/ as sysdba"

SQL*Plus: Release 9.2.0.4.0 - Production on Sun Oct 31 11:38:25 2004

Copyright (c) 1982, 2002, Oracle Corporation. All rights reserved.

Connected to:
Oracle9i Enterprise Edition Release 9.2.0.4.0 - Production
With the Partitioning option
JServer Release 9.2.0.4.0 - Production

SQL> set echo on
SQL> @ddlt
SQL> create or replace trigger ddl_deny
2 before create or alter or drop or truncate on database
3 declare
4 l_errmsg varchar2(100):= 'You have no permission to this operation';
5 begin
6 if ora_sysevent = 'CREATE' then
7 raise_application_error(-20001, ora_dict_obj_owner || '.' || ora_dict_obj_name || ' ' || l_errmsg);
8 elsif ora_sysevent = 'ALTER' then
9 raise_application_error(-20001, ora_dict_obj_owner || '.' || ora_dict_obj_name || ' ' || l_errmsg);
10 elsif ora_sysevent = 'DROP' then
11 raise_application_error(-20001, ora_dict_obj_owner || '.' || ora_dict_obj_name || ' ' || l_errmsg);
12 elsif ora_sysevent = 'TRUNCATE' then
13 raise_application_error(-20001, ora_dict_obj_owner || '.' || ora_dict_obj_name || ' ' || l_errmsg);
14 end if;
15
16 exception
17 when no_data_found then
18 null;
19 end;
20 /

Trigger created.

SQL>
SQL>
SQL> connect scott/tiger
Connected.
SQL> create table t as select * from test;
create table t as select * from test
*
ERROR at line 1:
ORA-00604: error occurred at recursive SQL level 1
ORA-20001: SCOTT.T You have no permission to this operation
ORA-06512: at line 5

SQL> alter table test add (id number);
alter table test add (id number)
*
ERROR at line 1:
ORA-00604: error occurred at recursive SQL level 1
ORA-20001: SCOTT.TEST You have no permission to this operation
ORA-06512: at line 7

SQL> drop table test;
drop table test
*
ERROR at line 1:
ORA-00604: error occurred at recursive SQL level 1
ORA-20001: SCOTT.TEST You have no permission to this operation
ORA-06512: at line 9

SQL> truncate table test;
truncate table test
*
ERROR at line 1:
ORA-00604: error occurred at recursive SQL level 1
ORA-20001: SCOTT.TEST You have no permission to this operation
ORA-06512: at line 11

 

我们可以看到,ddl语句都被禁止了,如果你不是禁止,可以选择把执行这些操作的用户及时间记录到另外的临时表中.以备查询.

 

 


历史上的今天...
    >> 2013-12-16文章:
    >> 2011-12-16文章:
    >> 2008-12-16文章:
    >> 2006-12-16文章:
    >> 2005-12-16文章:
           人生自是有情痴
           Day Day Up

无觅

By eygle on 2004-12-16 22:49 | Comments (3) | SQL.PLSQL | 111 |

3 Comments

你疯了,想删除表 ' || ora_dict_obj_name() || ' ?!!!!!' ||'你完了,警察已在途中.....

我删完就跑

删也删不掉,跑也跑不了,你惨了!

好玩,继续玩!


CopyRight © 2004~2020 云和恩墨,成就未来!, All rights reserved.
数据恢复·紧急救援·性能优化 云和恩墨 24x7 热线电话:400-600-8755 业务咨询:010-59007017-7040 or 7037 业务合作: marketing@enmotech.com