Re: Oracle date/time vs ingres date/time??

In article <1996Oct1.091049.2500_at_gems.vcu.edu>, Brainwave Surfer <agnew_at_gems.vcu.edu> writes
>Dear all,
>
>we are considering moving from Ingres to Oracle in the near future.
>
>We've been looking at all this, ingres' many files and tables against
>one Oracle "space" where all is contained, btree against extra indexes,
>etc. the most pressing thing, tho, is TIME. we store many time-related
>datapoints (30 second resolution data from an ICU), and will need to do
>time/date arithmetic. if that is not possible or even hard to do, we
>gotta look elsewhere.
>
>so, how does Oracle stack up? the market is swinging wildly to you
>guys, so it can't be too bad... ;-)
>

Oracle is very good on date arithmetic, but less good on times. All datetime manipulation is done on dates, with times as fractions of a day.

eg '10-oct-06 18:00:00' - '10-oct-06 06:00:00' = 0.5 (ie 12 hours)

30 seconds will be (30/(24*60) or 0.02083333333333 according to Windows calculator.

Default datetime format is 'dd-mon-yy' with the time element defaulting to 00:00:00. To insert a time alone or a date and time you need to use the TO_DATE function with a conversion format. THis may have performance implications. The format conversions are very flexible.

-- 
Jim Smith