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开发者_JAVA百科 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.

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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.

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The Easiest way: (Shutdown neccesary):

First, Connect as sysdba:

sqplus / as sysdba

Next, execute the following script:

alter system set nls_length_semantics=CHAR scope=both;
shutdown;
startup restrict;
alter database character set INTERNAL_USE WE8ISO8859P1;
shutdown;
startup;

It worked for me in a Oracle 12c Standard Two Edition

Taken from: https://www.elblogdelpibe.com/2015/05/como-solucionar-el-error-ora-12899.html (updated URL)

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replace line 6 by

ALTER DATABASE CHARACTER SET INTERNAL_USE AL32UTF8;

this solved my problem.

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Below worked for me in 19C.

Issue

import done in AL32UTF8 character set and AL16UTF16 NCHAR character set export done in WE8MSWIN1252 character set and AL16UTF16 NCHAR character set Warning: possible data loss in character set conversions

Steps

Database started in Restriction mode.

SQL> select * from nls_database_parameters where parameter='NLS_CHARACTERSET';

PARAMETER

VALUE

NLS_CHARACTERSET AL32UTF8

SQL> alter database character set WE8MSWIN1252; alter database character set WE8MSWIN1252 * ERROR at line 1: ORA-12712: new character set must be a superset of old character set

SQL> alter database character set INTERNAL_USE WE8MSWIN1252;

Database altered.

SQL> select * from nls_database_parameters where parameter='NLS_CHARACTERSET';

PARAMETER

VALUE

NLS_CHARACTERSET WE8MSWIN1252

SQL>

Cheers! RaJ...