cannot drop a user that is currently connected

Oracle'da ORA-01940: cannot drop a user that is currently connected
hatasi; bu user a ait session acik kaldigi icin silinemiyor

SYSTEM veya SYS ile login olunur

select sid, serial# from v$session where username = 'username';

SID SERIAL#
---------------------- ----------------------
156 450

alter system kill session '156,450';
drop user username cascade;


drop user username succeeded.