<snip> I would say start & duration, since you can always calculate end time from the other 2 and it's easier to do offsets than diffs between times. </snip> Depends on how you store you date/time fields. I think using native DBMS date/time data types are worthless and, instead, we opt to use unix timestamps, when possible (since the timestamp can't work well before 1970 or whatever it is) --Tony