转载：http://www.cnblogs.com/jay-xu33/p/5210098.html

1.cmd下,cd到oracle数据库软件的服务器端 如：D:\app\Administrator\product\11.2.0\dbhome_1\BIN

2.输入set ORACLE_SID=你想进入的数据库的那个sid

3.输入 sqlplus /nolog

4.将数据库启动到RESTRICTED模式下做字符集更改：

sql>conn /as sysdba

Connected.

sql>shutdown immediate;

Database closed.

Database dismounted.

ORACLE instance shut down.

sql>startup mount

ORACLE instance started.

Total System Global Area 236000356 bytes

Fixed Size 451684 bytes

Variable Size 201326592 bytes

Database Buffers 33554432 bytes

Redo Buffers 667648 bytes

Database mounted.

sql>ALTER SYSTEM ENABLE RESTRICTED SESSION;

System altered.

sql>ALTER SYSTEM SET JOB_QUEUE_PROCESSES=0;

sql>ALTER SYSTEM SET AQ_TM_PROCESSES=0;

sql>alter database open;

Database altered.

sql>ALTER DATABASE CHARACTER SET ZHS16GBK;

ALTER DATABASE CHARACTER SET ZHS16GBK

*

ERROR at line 1:

ORA-12712: new character set must be a superset of old character set

提示我们的字符集：新字符集必须为旧字符集的超集，这时我们可以跳过超集的检查做更改：

sql>ALTER DATABASE character set INTERNAL_USE ZHS16GBK;

sql>select * from v$nls_parameters;

略

19 rows selected.

重启检查是否更改完成：

sql>startup

Database opened.

sql>select * from v$nls_parameters;