>>>>>>>>>>>> Fabio wrote (2009-10-24 11:12:48): > Hello, > > I'm using Apache Derby to store hourly values of electricity > consumption. The values are used in an electricity market simulation > implemented in Java. > > Now because of DST, hourly values mean that (for central Europe): > - one day in March has 23 hours (there's no 2 a.m. to 3 a.m. during that > night) > - one day in October has 25 hours (2 a.m. to 3 a.m. appears twice during > that night) > > The data in October is published as: > (..) > 02:00 > 3A:00 > 3B:00 > 04:00 > 05:00 > (..) > > I have yet to find a good solution on how to store this data in the > database. Obviously, "3A:00" is not a valid time format. > Currently, I'm storing the consumption data in conjunction with a field > named "hour_in_year" (1-8760) but having the date and time is more handy > for sql select queries. > > Any ideas how to support the "curse of dst" in a time field?
The obvious solution is to store dates and times as UTC in your databases, and handle time zones dst in your application. I don't know the nature of your application, but if you implement special treatmet of 3A:00 and 3B:00 it is still of no use if your application is to be run in some Brazilian locale where the change to and from dst happens at 00:00/01:00 instead of 02:00/03:00 as in most countries. Bernt > > Fabio
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