SQL Error: ORA-12712: new character set must be a superset of old character set

Question

I want to change character set of oracle database from 'WE8MSWIN1252' to 'AL32UTF8'

I tried to execute following steps from the link (http://download.oracle.com/docs/cd/B10501_01/server.920/a96529/ch10.htm#1009580):

Shut down the database, using either a SHUTDOWN IMMEDIATE or a SHUTDOWN NORMAL statement. Do a full backup of the database because the ALTER DATABASE CHARACTER SET statement cannot be rolled back. Complete the following statements:

STARTUP MOUNT;
ALTER SYSTEM ENABLE RESTRICTED SESSION;
ALTER SYSTEM SET JOB_QUEUE_PROCESSES=0;
ALTER SYSTEM SET AQ_TM_PROCESSES=0;
ALTER DATABASE OPEN;
ALTER DATABASE CHARACTER SET AL32UTF8;

But when i execute the above statement, I am getting the following error

SQL Error: ORA-12712: new character set must be a superset of old character set

Can anyone please help me in resolving this issue.

Answer 1

For an ALTER DATABASE CHARACTER SET statement to execute successfully, two conditions must be fulfilled:

• Each and every character in the current character set is available in the new character set.
• Each and every character in the current character set has the same code point value in the new character set. (ie: the old charset must be a subset of the new one)

Because WE8MSWIN1252 is not a strict subset of AL32UTF8 this statement will fail (example: the pound sign is A3 in hex in WE8MSWIN1252, but in AL32UTF8 it is C2 A3).

You'll need to use CSALTER to do this migration.

Refer to: Character Set Migration.