一. 相关概念
关于DB_NAME,INSTANCE_NAME 的定义，参考我的Blog：
DBID,SID,DB_NAME,DB_DOMAIN,INSTANCE_NAME,DB_UNIQUE_NAME,SERVICE_NAMES 及监听参数的说明
http://blog.csdn.net/tianlesoftware/archive/2010/12/20/6086066.aspx
关于NID命令的使用，参考Blog：
How to Change the DBID and the DBNAME by using NID [ID 224266.1]
http://blog.csdn.net/tianlesoftware/archive/2010/12/20/6087570.aspx
在这篇blog里提到了一下信息：
The NID (New Database ID)is a new utility introduced with Oracle 9.2. The NID utility allows you to change only the DBNAME, or only the DBID or both DBNAME and DBID in the same command.
-- 我们可以使用NID 命令只修改DBNAME， 或者只修改DBID，或者2个都修改。
他们的区别如下：
1. If you change the DBID you must open the database with the RESETLOGS option, which re-creates the online redo logs and resets their sequence to 1.
-- 修改DBID，必须要用resetlogs 打开数据库。 这个在之前的DBID 的介绍里说过，因为DBID 存在与数据文件，redo log 和控制文件。 所以如果修改了DBID， 则必须要使用resetlogs打开。
2. If you change the DBNAME without changing the DBID then this does not require you to open with the RESETLOGS option, so database backups and archived logs are not invalidated. You must change the DB_NAME initialization parameter after a database name change to reflect the new name. Also, you may have to re-create the Oracle password file. If you restore an old backup of the control file (before the name change, then you should use the initialization parameter file and password file from before the database name change.
关于NID 修改DBID 和DBNAME的具体3种用法，参考之前的那片文章。
在这里还有一点要注意， 就是orapwSID 和 initSID.ora 是和INSTANCE_NAME 对应的，如果这个参数修改了，那么这2个文件也需要修改并与INSTANCE_NAME 对应。 修改这个参数也很简单，就是在init 文件里指定一个名称即可，如：*.INSTANCE_NAME=orcl
二. 修改DBID, DBNAME步骤
在这里，只演示一下修改DBID 和 DBNAME的操作。 并不修改INSTANE_NAME.
步骤如下：
1. Backup of the database.
2. Shutdown IMMEDIATE of the database
3. STARTUP MOUNT
4. Open one session and run NID with sysdba privileges
% nid TARGET=SYS/password@test_db DBNAME=test_db2
- the value of DBNAME is the new dbname of the database
5. After DBNEWID successfully changes the DBID,Shutdown IMMEDIATE of the database
6. Set the DB_NAME initialization parameter in the initialization parameter file to the new database name.
7. Create a new password file.
8. Startup of the database with open resetlogs
在修改之前，先看一下数据库的参数：
SQL> select name,dbid,db_unique_name from v$database;
NAME DBID DB_UNIQUE_NAME
--------- ---------- ------------------------------
ORCL 1264931370 orcl
SQL> select instance_name from v$instance;
INSTANCE_NAME
----------------
orcl
2.1 shutdown database
SQL> shutdown immediate
Database closed.
Database dismounted.
ORACLE instance shut down.
2.2 Startup mount
SQL> startup mount;
ORACLE instance started.
Total System Global Area 360710144 bytes
Fixed Size 1219424 bytes
Variable Size 109053088 bytes
Database Buffers 247463936 bytes
Redo Buffers 2973696 bytes
Database mounted.
2.3 Run NID command
[oracle@singledb bdump]$ nid
DBNEWID: Release 10.2.0.1.0 - Production on Mon Dec 20 14:26:13 2010
Copyright (c) 1982, 2005, Oracle. All rights reserved.
Keyword Description (Default)
----------------------------------------------------
TARGET Username/Password (NONE)
DBNAME New database name (NONE)
LOGFILE Output Log (NONE)
REVERT Revert failed change NO
SETNAME Set a new database name only NO
APPEND Append to output log NO
HELP Displays these messages NO
[oracle@singledb bdump]$ nid target=/ dbname=dave
DBNEWID: Release 10.2.0.1.0 - Production on Mon Dec 20 14:27:13 2010
Copyright (c) 1982, 2005, Oracle. All rights reserved.
Connected to database ORCL (DBID=1264931370)
Connected to server version 10.2.0
Control Files in database:
/u01/app/oracle/oradata/orcl/control01.ctl
/u01/app/oracle/oradata/orcl/control02.ctl
/u01/app/oracle/oradata/orcl/control03.ctl
Change database ID and database name ORCL to DAVE? (Y/[N]) => Y --手工输入
Proceeding with operation
Changing database ID from 1264931370 to 801102850
Changing database name from ORCL to DAVE
Control File /u01/app/oracle/oradata/orcl/control01.ctl - modified
Control File /u01/app/oracle/oradata/orcl/control02.ctl - modified
Control File /u01/app/oracle/oradata/orcl/control03.ctl - modified
Datafile /u01/app/oracle/oradata/orcl/system.256.736598559 - dbid changed, wrote new name
Datafile /u01/app/oracle/oradata/orcl/undotbs1.258.736598599 - dbid changed, wrote new name
Datafile /u01/app/oracle/oradata/orcl/sysaux.257.736598563 - dbid changed, wrote new name
Datafile /u01/app/oracle/oradata/orcl/users.259.736598641 - dbid changed, wrote new name
Datafile /u01/app/oracle/oradata/orcl/temp.263.736599505 - dbid changed, wrote new name
Datafile /u01/app/oracle/oradata/orcl/temp01.dbf - dbid changed, wrote new name
Control File /u01/app/oracle/oradata/orcl/control01.ctl - dbid changed, wrote new name
Control File /u01/app/oracle/oradata/orcl/control02.ctl - dbid changed, wrote new name
Control File /u01/app/oracle/oradata/orcl/control03.ctl - dbid changed, wrote new name
Instance shut down
Database name changed to DAVE.
Modify parameter file and generate a new password file before restarting.
Database ID for database DAVE changed to 801102850.
All previous backups and archived redo logs for this database are unusable.
Database is not aware of previous backups and archived logs in Recovery Area.
Database has been shutdown, open database with RESETLOGS option.
Succesfully changed database name and ID.
DBNEWID - Completed succesfully.
[oracle@singledb bdump]$
2.4 修改PFILE 里的DB_NAME参数
[oracle@singledb dbs]$ cat initorcl.ora
...
*.db_name='dave'
...
2.5 用pfile启动数据库，并用resetlogs 打开
SQL> startup mount pfile='/u01/app/oracle/product/10.2.0/db_1/dbs/initorcl.ora';
ORACLE instance started.
Total System Global Area 360710144 bytes
Fixed Size 1219424 bytes
Variable Size 109053088 bytes
Database Buffers 247463936 bytes
Redo Buffers 2973696 bytes
Database mounted.
SQL> alter database open resetlogs;
Database altered.
2.7 查看修改之后的信息
SQL> select name,dbid,db_unique_name from v$database;
NAME DBID DB_UNIQUE_NAME
--------- ---------- ------------------------------
DAVE 801102850 dave
SQL> select instance_name from v$instance;
INSTANCE_NAME
----------------
orcl
SQL>
在这里看到， db_name 和DBID 都修改了，但是instance_name 没有修改。 在官网的文档里提到了重建密码文件，因为我的instance_name没有修改，所以我没有进行重建。
------------------------------------------------------------------------------
Blog： http://blog.csdn.net/tianlesoftware
网上资源： http://tianlesoftware.download.csdn.net
相关视频：http://blog.csdn.net/tianlesoftware/archive/2009/11/27/4886500.aspx
DBA1 群：62697716(满); DBA2 群：62697977(满)
DBA3 群：62697850 DBA 超级群：63306533;
聊天 群：40132017
--加群需要在备注说明Oracle表空间和数据文件的关系，否则拒绝申请