--查看oracle数据库字符集：
　　select userenv('language') from dual;
　　查询结果：
　　SIMPLIFIED CHINESE_CHINA.AL32UTF8
　　--修改oracle数据库字符集：（在SQL Plus中）
　　sql> conn / as sysdba;
　　sql> shutdown immediate;
　　database closed.
　　database dismounted.
　　oracle instance shut down.
　　sql> startup mount;
　　oracle instance started.
　　total system global area  135337420 bytes
　　fixed size                          452044 bytes
　　variable size                     109051904 bytes
　　database buffers              25165824 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 internal_use JA16SJIS;
　　sql> shutdown immediate;
　　sql> startup;