Oracle10g: Change the character set of the database

It may happen that after you install or configure a new Oracle database we realize that the character set chosen during installation is not correct. What we may happen in cases like this is to delete the database and reconfigure it or worse ...But you do not. We can change the character set stopping the database, looking up strictly by changing the settings and restart the database. Howto:
 

- First we connect to the database 

$ sqlplus sys/pwd@prod as sysdba
 

- We stop the database 

SQL>SHUTDOWN IMMEDIATE;

- We raise strictly * 

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

- Change the character map 

SQL>ALTER DATABASE CHARACTER SET <new characters map>;

- Restart the database and yata 

SQL>SHUTDOWN IMMEDIATE;
SQL>STARTUP;