在Centos6.5上安装Oracle11g没有设定字符集，采用的是操作系统默认字符集：WE8MSWIN1252，将字符集修改为：ZHS16GBK。
[oracle@xserver ~]$ sqlplus / as sysdba
SQL*Plus: Release 11.2.0.1.0 Production on Sat Dec 28 12:17:01 2013
Copyright (c) 1982, 2009, Oracle. All rights reserved.
Connected to:
Oracle Database 11g Enterprise Edition Release 11.2.0.1.0 - 64bit Production
With the Partitioning, OLAP, Data Mining and Real Application Testing options
SQL> select * from nls_database_parameters where parameter='NLS_CHARACTERSET';
PARAMETER
------------------------------
VALUE
--------------------------------------------------------------------------------
NLS_CHARACTERSET
WE8MSWIN1252
SQL> shutdown immediate
Database closed.
Database dismounted.
ORACLE instance shut down.
SQL> startup mount
ORACLE instance started.
Total System Global Area 1603411968 bytes
Fixed Size 2213776 bytes
Variable Size 1056966768 bytes
Database Buffers 536870912 bytes
Redo Buffers 7360512 bytes
Database mounted.
SQL> alter system enable restricted session;
System altered.
SQL> show parameter job_queue_processes;
NAME TYPE VALUE
------------------------------------ ----------- ------------------------------
job_queue_processes integer1000
SQL> alter system set job_queue_processes=0;
System altered.
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
SQL> alter database character set internal_use ZHS16GBK;
Database altered.
SQL> select * from nls_database_parameters where parameter='NLS_CHARACTERSET';
PARAMETER
------------------------------
VALUE
--------------------------------------------------------------------------------
NLS_CHARACTERSET
ZHS16GBK
SQL> shutdown immediate
Database closed.
Database dismounted.
ORACLE instance shut down.
SQL> startup mount
ORACLE instance started.
Total System Global Area 1603411968 bytes
Fixed Size 2213776 bytes
Variable Size 1056966768 bytes
Database Buffers 536870912 bytes
Redo Buffers 7360512 bytes
Database mounted.
SQL> alter system set job_queue_processes=1000;
System altered.
SQL> alter database open;
Database altered.
SQL>
