SQL & PL/SQL :: Created Trigger On Database Level In System Schema

I have created trigger on database level in system schema. While i am creating new tables in system schema, trigger logged the entry but when i am creating table in scott schema it is not working for that.

CREATE OR REPLACE TRIGGER ddltrigger
AFTER DDL ON DATABASE
BEGIN
INSERT INTO aud_log
(user_name, ddl_date, ddl_type, object_type,
owner, object_name
)
VALUES (ora_login_user, SYSDATE, ora_sysevent, ora_dict_obj_type,
ora_dict_obj_owner, ora_dict_obj_name
);
END;