Re: Oracle dates and timezones

/ hpcc01:comp.databases.oracle / Austin Moseley <\"moseba_at_audv55.aud.alcatel.com'> / 7:09 pm Mar 28, 1996 /

>How would the system know the time zone? Who would tell it?
>How many timezones are there in the world? What if Alaska time
>becomes PST? Or we dump daylight savings time?

    Those are not events that 'just happen'. There will be lots of discussions     before those go into effects because it affects so many people. The kernel     groups are always tracking those changes, we don't have to.

    If you don't believe me, try on any Unix : "cal 9 1752" and     you'll see a month with only 19 days.

   September 1752
 S M Tu W Th F S

       1 2 14 15 16
17 18 19 20 21 22 23
24 25 26 27 28 29 30

    That was when Great Britain and its colonies - including the American     colonies- switched from the Julian to the Gregorian calendar.     As a side effect, George Washington who was born 11 Feb 1732 in the Julian     Calendar system, now has his birthday on 22 Feb.

>Most organizations which are international, like the weather
>bureaus, the military, aviation, track zulu or GMT time.

    From a white paper I wrote about Time:

    GMT is a civil time, not scientific time. It is decreed by the Brittish     Parliament, not by any algorithm/measurement as people would think.     Here are excerpt from discussions about GMT.

 1:51 am  Oct 10, 1994     comp.protocols.time.ntp             Note 2121 of 2137
                  Looking for Current Timezone definitions     Resp   7 of  11
zlsiial_at_cfs2.mcc.ac.uk               A O V Le Blanc at University of Manchester

In article <781565557snz_at_tcs01.demon.co.uk> david_at_tcs01.demon.co.uk writes:
>
>Parliament must decide the date more than a few weeks beforehand, surely,
>otherwise how could diaries give the dates for time changes?

Two or three years ago there was a problem. Parliament failed to confirm the date because of a heavy work load, and the clocks changed a week after the date in the diaries. Our University diaries have not put the BST/GMT changeover dates in ever since.

• Owen LeBlanc_at_mcc.ac.uk ...... ...... GMT = Greenwich Mean Time. It's ambiguous, and is now used (although not in astronomy) in the sense of UTC in addition to the earlier sense of UT. Prior to 1925, it was reckoned for astronomical purposes from Greenwich mean noon (12h UT)

       "NO - it pains me to say it (given that it was invented here) but the 
       term GMT should not now be used - it has no formal definition." 
		 Philip Taylor at Royal Greenwich Observatory,
                     pbt_at_mail.ast.cam.ac.uk.