NLS Parametrs. Very URGENT, PLS HELP

I want to know how to change NLS PARAMTERS. Please help me with the command.

I am trying this and I am getting errors. Pls help immd.

SQL> alter session set nls_CHARACTERSET='WE8ISO8859P15';
alter session set nls_CHARACTERSET='WE8ISO8859P15'
*
ERROR at line 1:
ORA-00922: missing or invalid option

Quote:

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Originally posted by dbafreak
I am trying this and I am getting errors. Pls help immd.

SQL> alter session set nls_CHARACTERSET='WE8ISO8859P15';
alter session set nls_CHARACTERSET='WE8ISO8859P15'
*
ERROR at line 1:
ORA-00922: missing or invalid option

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Change it in the registry !!!

I am using NT and 8i. Please help.

I got the procedure to change. But its giving the following error:

ORA-12712: new character set has to be a superset of old character set.

I am executing the following commands -

SQL> STARTUP MOUNT;
SQL> ALTER SYSTEM ENABLE RESTRICED SESSION;
SQL> ALTER SYSTEM SET JOB_QUEUE_PROCESSES=0;
SQL> ALTER DATABASE OPEN;

SQL>alter database set characterset WE8ISO8859P15;

error
ORA-12712: new character set has to be a superset of old character set.


My old characterset is WE8ISO8859P1

obviously the new is a superset of the old. Why am I getting this error??