What I do is I have a LastUpdate column in my Oracle tables. I then use an Insert/Update trigger to populate this column with the SYSDATE. The following is an example Insert/Update trigger:

create or replace trigger ADDRESS_HISTORY_BEFORE_INSUPDT
before insert or update on npdes.ADDRESS_HISTORY for each row
declare
v_Id   Number;
v_User Char(8);
v_Date Date;
BEGIN
 select USER into v_User from dual;
 :new.Updated_By := v_User;
 select SYSDATE into v_Date from dual;
 :new.Last_Update := v_Date;
 If :new.KeyID Is Null or :new.KeyID < 1 Then
    select s_npdes_ADDRESS_HISTORY.nextval into v_Id from dual;
    :new.KeyID := v_Id;
 End If;
End;
/