Trigger to log DROP operations on schema

create TABLE drop_log (
user_name     VARCHAR2(30),
machine varchar(30),
ddl_date      DATE,
ddl_type      VARCHAR2(30),
object_type   VARCHAR2(18),
owner         VARCHAR2(30),
object_name   VARCHAR2(128))
;


CREATE OR REPLACE TRIGGER drop_trig
before drop
on kpi.schema
declare
machine varchar(30);

BEGIN
 select machine into machine from v$session where sid = ( select sid from v$mystat where rownum=1 );

  INSERT INTO drop_log
  (user_name, machine, ddl_date, ddl_type,
   object_type, owner,
   object_name)
  VALUES
  (ora_login_user, machine, SYSDATE, ora_sysevent,
   ora_dict_obj_type, ora_dict_obj_owner,
   ora_dict_obj_name);
END drop_trig;
/

select * from drop_log;