Oracle import failed with length exceeded

Oracle Import failed, the length of the ORA-12899, is the character set caused by the Chinese in the UTF-8 accounted for 3 bytes, zhs16gbk accounted for 2 bytes, and the source DMP file character set is ZHS16GBK the data poured out of the library, Now to import to the target character set of UTF-8 library, so will appear ORA-12899 in fact, just modify the Oracle character set can be a good solution to this problem; Follow the commands given below to execute them sequentially, 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 ZHS16GBK;
ALTER DATABASE CHARACTER SET ZHS16GBK
*error at line 1:
Ora-12712:new character set must be a superset of the old character set

Character set is not compatible, the internal_use instruction does not check the character set superset at this time:

Sql>alter DATABASE CHARACTER SET internal_use ZHS16GBK;
Sql>shutdown IMMEDIATE
Sql>startup

Oracle import failed with length exceeded