Oracle服务器字符集为WE8ISO8859P1，使用DTS将数据从MS SQL Server2000导入到Oracle后，汉字无法正常显示。

刚开始，我认为是Oracle客户端和服务器端字符集不同引起的，但是把2者的字符集改成一样，还是不行。

通过在网上查资料，最后认为，DTS在导入数据时，默认Oracle字符集是支持汉字的，而数据传过来后，Oracle发现自己不支持，就做了一个转换。即，这个数据无论如何是不能恢复了，只能从SQL Server重新导入。

需要修改Oracle服务器的字符集。

SQL> shutdown immediate;
Database closed.
Database dismounted.
ORACLE instance shut down.
SQL> startup mount;
ORACLE instance started.

Total System Global Area  219223120 bytes
Fixed Size                   451664 bytes
Variable Size             201326592 bytes
Database Buffers           16777216 bytes
Redo Buffers                 667648 bytes
Database mounted.
SQL> alter session set sql_trace=true;

Session altered.

SQL> alter system enable restricted session;

System altered.

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 session set events '10046 trace name context forever,level 12';

Session altered.

SQL> alter database character set INTERNAL_USE ZHS16GBK;
alter database character set INTERNAL_USE ZHS16GBK
*
ERROR at line 1:
ORA-12721: operation cannot execute when other sessions are active

SQL> alter system set aq_tm_processes=0;

System altered.

SQL> alter database character set INTERNAL_USE ZHS16GBK;

Database altered.

重新启动服务器后，再用DTS导入汉字，就一切正常了。