一.准备修改。首先必须用sys连接。
1.修改sys密码.用其他dba权限的账户登陆后输入：alter user sys identified by 新密码;
2.连接刚刚修改的sys（要在登陆状态下）,CONNECT SYS／密码 as sysdba;
二.开始修改:
[oracle@pdc oracle]$ sqlplus / as sysdba
SQL*Plus: Release 10.2.0.1.0
- Production on Fri Jun 6 08:45:34 2008
Copyright (c) 1982, 2005,
Oracle. All rights reserved.
Connected to:
Oracle Database
10g Enterprise Edition Release 10.2.0.1.0 - Production
With the Partitioning,
OLAP and Data Mining options
SQL> SHUTDOWN IMMEDIATE;
Database
closed.
Database dismounted.
ORACLE instance shut down.
SQL>
STARTUP nomount;
ORACLE instance started.
SQL> ALTER DATABASE mount
exclusive;
Database altered.
SQL> ALTER SYSTEM enable restricted
session;
System altered.
SQL> ALTER SYSTEM SET
JOB_QUEUE_PROCESSES=0;
System altered.
SQL> ALTER SYSTEM SET
AQ_TM_PROCESSES=0;
System altered.
SQL> ALTER DATABASE
OPEN;
Database altered.
SQL> ALTER DATABASE CHARACTER SET
UTF8;
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(UTF8可以根据需要更改，如ZHS16GBK
)：
SQL>
ALTER DATABASE CHARACTER SET INTERNAL_USE UTF8;
Database
altered.
注意：如果没有大对象，在使用过程中进行语言转换没有什么影响，具体过程如下（切记设定的字符集必须是ORACLE支持，不然不能start）