一朋友问我，想查看一下数据库中，表里边一个字段哪天修改字段长度了，我想到了用数据库审计来实现，做个实验，来看下。

朋友那边数据库版本是ORACLE10g,10g版本默认没开启审计功能，需要开启审计。

C:\Documents and Settings\Administrator>sqlplus / as sysdba

SQL*Plus: Release 10.2.0.3.0 - Production on 星期一 12月 30 09:57:39 2013

Copyright (c) 1982, 2006, Oracle.  All Rights Reserved.

Connected to:

Oracle Database 10g Enterprise Edition Release 10.2.0.3.0 - Production

With the Partitioning, OLAP and Data Mining options

SQL> show parameter audit

NAME                                 TYPE

------------------------------------ ----------------------

VALUE

------------------------------

audit_file_dest                      string

D:\ORACLE\PRODUCT\10.2.0\ADMIN

\YING8\ADUMP

audit_sys_operations                 boolean

FALSE

audit_trail                          string

NONE

SQL> alter system set audit_trail=DB_EXTENDED ;

alter system set audit_trail=DB_EXTENDED

*

ERROR at line 1:

ORA-02095: specified initialization parameter cannot be modified

SQL> alter system set audit_trail=DB_EXTENDED scope=spfile;--静态参数，这里的DB_EXTENDED具有捕获SQL的功能。

System altered.

SQL> shutdown immediate

Database closed.

Database dismounted.

ORACLE instance shut down.

SQL> startup

ORACLE instance started.

Total System Global Area  583008256 bytes

Fixed Size                  1291868 bytes

Variable Size             213911972 bytes

Database Buffers          360710144 bytes

Redo Buffers                7094272 bytes

Database mounted.

Database opened.

SQL> show parameter audit

NAME                                 TYPE

------------------------------------ ----------------------

VALUE

------------------------------

audit_file_dest                      string

D:\ORACLE\PRODUCT\10.2.0\ADMIN

\YING8\ADUMP

audit_sys_operations                 boolean

FALSE

audit_trail                          string

DB_EXTENDED

SQL> conn wzz/wzz

Connected.

SQL> desc wh2

ERROR:

ORA-04043: object wh2 does not exist

SQL> create table wh2 (id int);

Table created.

SQL> audit alter on wh2 by access;

Audit succeeded.

SQL> select * from dba_audit_trail;

no rows selected

SQL> alter table wh2 add name varchar2(20);

Table altered.

SQL> select timestamp,owner,obj_name,action,action_name,sql_text from dba_audit_trail;

TIMESTAMP        OWNER OBJ_N     ACTION ACTION_NAME                                              SQL_TEXT

---------------- ----- ----- ---------- -------------------------------------------------------- ------------------------------

30-12月-2013     WZZ   WH2           15 ALTER TABLE                                              alter table wh2 add name varch

ar2(20)