oracle8.1.6
declare
owner_id acs_objects.creation_user%TYPE;
begin
select creation_user into owner_id
from acs_objects
where object_id = :pres_item_id;
if (owner_id <> :user_id) then
acs_permission.revoke_permission(:pres_item_id, :user_id, :privilege);
end if;
end;