常见情形:从服务器备份Oracle数据库后再到本地机器上还原Oracle数据库的时候经常会碰见数据库字符编码不一致的情况，可以用以下命令来修改本地的Oracle数据库字符编码，然后顺利还原Oracle数据库到本地机器上

操作指令：

[oracle@gpdb ~]$ sqlplus /nolog

SQL> conn /as sysdba;

SQL>select userenv('language') from dual;

SQL>SHUTDOWN IMMEDIATE

SQL>STARTUP MOUNT

SQL>ALTER SYSTEM ENABLE RESTRICTED SESSION;

SQL>ALTER SYSTEM SET JOB_QUEUE_PROCESSES=0;

SQL>ALTER SYSTEM SET AQ_TM_PROCESSES=0;

SQL>ALTER DATABASE OPEN;

SQL>ALTER DATABASE CHARACTER SET INTERNAL_USE US7ASCII;

SQL>SHUTDOWN IMMEDIATE;

SQL>STARTUP;

SQL>select userenv('language') from dual;

常见的Oracle字符集有ZHS16GBK、AL32UTF8、US7ASCII等