select * from v$nls_parameters;

sqlplus "/ as sysdba"

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 NATIONAL CHARACTER SET INTERNAL_USE UTF8;

SQL> SHUTDOWN IMMEDIATE

SQL> STARTUP