Oracle-如何获得数据库的DBID

在进行数据库恢复的过程中,很多时候我们需要知道Oracle数据库的DBID,通常有以下几种方法可以获得数据库的DBID. 1.查询v$database获得由于DBID在控制文件和数据文件中都存在记录,所以假如能够mount数据库就可以查询v$database视图获得. SQL> alter database mount; Database altered. SQL> select dbid from v$database; DBID ---------- 3152029224 SQL> 2.在nomount状态时假如数据库配置了自动控制文件备份(Oracle9i),并且名称是缺省的,那么我们可以从自动备份文件获得DBID. [oracle@jumper dbs]$ cd $ORACLE_HOME/dbs
[oracle@jumper dbs]$ ll c-*
-rw-r----- 1 oracle dba 3375104 Dec 21 11:13 c-3152029224-20051221-00
-rw-r----- 1 oracle dba 3358720 Jan 21 14:03 c-3152029224-20060121-00
-rw-r----- 1 oracle dba 3358720 Jan 21 14:08 c-3152029224-20060121-01 这里的3152029224就是DBID. 3.从自动备份中恢复需要或缺DBID进行恢复通常是因为丢失了所有的控制文件.在恢复时会碰到错误. [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 假如存在自动备份,我们通常可以直接恢复控制文件,mount数据库之后就好办了: RMAN> restore controlfile from '/opt/oracle/product/9.2.0/dbs/c-3152029224-20051221-00';Starting restore at 05-FEB-06using channel ORA_DISK_1channel ORA_DISK_1: restoring controlfilechannel ORA_DISK_1: restore completereplicating controlfileinput filename=/opt/oracle/oradata/conner/control01.ctloutput filename=/opt/oracle/oradata/conner/control02.ctloutput filename=/opt/oracle/oradata/conner/control03.ctlFinished restore at 05-FEB-06 4.直接从幸存的文件中读取由于DBID存在于数据文件及控制文件中,所以我们可以通过PL/SQL程序直接从文件中读取: SQL> select eygle.get_dbid('/opt/oracle/oradata/conner','user02.dbf') from dual;
EYGLE.GET_DBID('/OPT/ORACLE/OR
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3152029224 SQL> select dbid from v$database; DBID
----------
3152029224 这种方法仅为测试爱好所致,不被推荐.