David Giragosian wrote: > Does Daylight Savings alter Zulu time? (I'm guessing "yes"). How did the > military deal with that? > > I use a date-time field as a primary key in db tables that get an > insert a > minute. I had to jump through a number of hoops to turn off DST on the > (RH > Linux) server. > > David > UTC (or GMT, or Zulu, or Z) does not observe Daylight Savings Time. In any database that you store timestamps and need to know exactly what that timestamp means you should use UTC, then use application logic to translate to the users time zone. Another option would be to store epoch time (seconds since the OS's epoch) and work the same result from that, I prefer storing human-readable timestamps even if you have to do the datemath in your head to read them in your own timezone. Epoch does not count leap-seconds like UTC so it can be off by a tiny bit at any given time. Epoch time also differs on different operating systems - Unix is 1970-01-01 at 00:00:00 UTC, Windows seems to use 1601-01-01 at 00:00:00 UTC... I don't know if that would ever matter though - I imagine the database server would mask this and the application would port to windows without problems (no idea.) UTC has no DST from: http://en.wikipedia.org/wiki/Time_zone >> Due to daylight saving time, UTC is local time at the Royal Observatory, Greenwich <http://en.wikipedia.org/wiki/Royal_Observatory%2C_Greenwich> only between 01:00 UTC on the last Sunday in October and 01:00 UTC on the last Sunday in March. For the rest of the year, local time there is UTC+1 <http://en.wikipedia.org/wiki/UTC%2B1>, known in the United Kingdom <http://en.wikipedia.org/wiki/United_Kingdom> as British Summer Time <http://en.wikipedia.org/wiki/British_Summer_Time> (BST). Similar circumstances apply in many places. << ** Travis Doherty TixTime -- PHP General Mailing List (http://www.php.net/) To unsubscribe, visit: http://www.php.net/unsub.php
