因为DBID在控制文件和数据文件里都存在记录,所以假设可以mount数据库就行查询v$database视图获得.
SQL> alter database mount;
Database altered.
SQL> select dbid from v$database;
DBID
----------
1363251591
2.在nomount状态时
假设数据库配置了自己主动控制文件备份(Oracle9i),而且名称是缺省的,那么我们能够从自己主动备份文件获得DBID.
[oracle@jumper dbs]$ cd $ORACLE_HOME/dbs
[oracle@jumper dbs]$ ll c-*
-rw-r----- 1 oracle dba 3375104 Dec 21 11:13 c-1363251591-20051221-00
-rw-r----- 1 oracle dba 3358720 Jan 21 14:03 c-1363251591-20060121-00
-rw-r----- 1 oracle dba 3358720 Jan 21 14:08 c-1363251591-20060121-01
这里的1363251591就是DBID。在10g中，使用Flash Recovery Area。则没有这个命名规则。
3.从自己主动备份中恢复
须要或缺DBID进行恢复一般是由于丢失了全部的控制文件.在恢复时会遇到错误.
[oracle@jumper dbs]$ rman target /
Recovery Manager: Release 9.2.0.4.0 - Production
Copyright (c) 1995, 2002, Oracle Corporation. All rights reserved.
connected to target database: conner (not mounted)
RMAN> restore controlfile from autobackup;
Starting restore at 05-FEB-06
using target database controlfile instead of recovery catalog
allocated channel: ORA_DISK_1
channel ORA_DISK_1: sid=11 devtype=DISK
RMAN-00571: ===========================================================
RMAN-00569: =============== ERROR MESSAGE STACK FOLLOWS ===============
RMAN-00571: ===========================================================
RMAN-03002: failure of restore command at 02/05/2006 20:47:25
RMAN-06495: must explicitly specify DBID with SET DBID command
假设存在自己主动备份,我们通常能够直接恢复控制文件,mount数据库之后就好办了:
RMAN> restore controlfile from '/opt/oracle/product/9.2.0/dbs/c-1363251591-20051221-00';
Starting restore at 05-FEB-06
using channel ORA_DISK_1
channel ORA_DISK_1: restoring controlfile
channel ORA_DISK_1: restore complete
replicating controlfile
input filename=/opt/oracle/oradata/conner/control01.ctl
output filename=/opt/oracle/oradata/conner/control02.ctl
output filename=/opt/oracle/oradata/conner/control03.ctl
Finished restore at 05-FEB-06
4.直接从幸存的文件里读取
因为DBID存在于数据文件及控制文件里,所以我们能够通过PL/SQL程序直接从文件里读取:
SQL> select eygle.get_dbid('/opt/oracle/oradata/conner','user02.dbf') from dual;
EYGLE.GET_DBID('/OPT/ORACLE/OR
------------------------------
1363251591
SQL> select dbid from v$database;
DBID
----------
1363251591
事实上更简单的，用BBED就好了。
这样的方法仅为測试兴趣所致,不被推荐.
--此处为eygle自己定义的函数 （抽时间我会补上）
5、通过dump数据文件获取dbid：
SYS@orcl> alter system dump datafile 'D:APPADMINISTRATORORADATAORCLUSERS01.DBF' block 1000;
系统已更改。
SYS@orcl> select tracefile from v$process where addr in (select paddr from v$session where sid in (select sid from v$mystat));
--查看trace文件：Db ID=1363251591
TRACEFILE
------------------------------------------------------------------------------
d:appadministratordiag
dbmsorclorcl raceorcl_ora_6740.trc
Start dump data block from file D:APPADMINISTRATORORADATAORCLUSERS01.DBF minblk 0 maxblk -1
V10 STYLE FILE HEADER:
Compatibility Vsn = 186646528=0xb200000
Db ID=1363251591=0x51419187, Db Name='ORCL'
Activation ID=0=0x0
Control Seq=10579=0x2953, File size=1600=0x640
File Number=4, Blksiz=8192, File Type=3 DATA
Dump all the blocks in range:
...
-------------------------------
Dylan Presents.