修改Oracle数据库字符集字符集修改完成，但是非常不建议在这种在数据库上修改字符集，非常容易出问题。

1.Oracle server端的字符集查询

select userenv('language') from dual;

其中NLS_CHARACTERSET 为server端字符集 NLS_LANGUAGE 为 server端字符显示形式

2.server端字符集修改

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; 
System altered. 

SQL> ALTER SYSTEM SET AQ_TM_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

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; 
Database altered. 
SQL> select * from v$nls_parameters; 
略 
19 rows selected.

重启检查是否更改完成：

SQL> shutdownimmediate; 
Database closed. 
Database dismounted. 
ORACLE instance shut down. 
SQL> startup 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. 
Database opened. 
SQL> select * from v$nls_parameters;

字符集修改完成，但是非常不建议在这种在数据库上修改字符集，非常容易出问题。