Subject Re: [firebird-support] Re: Date Range
Author Lester Caine
Martijn Tonies wrote:

>>I do see that you're working with genealogy, I don't even follow your
>>calendar reasoning.
>>However, assuming the simple bits that I thought was the Julian
>>calendar (leapyears every 4th year, except those ending in 00 which is
>>not divisible by 400), I think the calendar should repeat itself every
>>2800 years. Hence, if you add 5600 years to each and every value, you
>>should be able to store dates from before the beginning of
>>'Astronomical calculations' (1 January 4713 BC) to about 2395 years
>>from now. Before then, I expect Firebird 5 to have been released, and
>>I'm certain a solution to your date problem will have been found.

Of cause you then add in the fact that the day count in FB has an offset
as well ;) Some date in December 1899?

> If it only was that easy :-)

We haven't added in WHEN the day starts yet :)

> During the years, sometimes a couple of days have gone "missing".

And they are all documented, along with lots of other useful stuff such
as years changing on 25th March rather than 1st January. So as well as
slipping dates, the 1st January to 25th March are also missing from odd
years in a range of countries.

> And depending on where you live, this could have happened sooner
> or later. eg, the Russian October Revolution is celebrated in November,
> I believe, because 2 weeks are gone :-) ... Or the other way around,
> for that matter.
> And the Russians were years later with adjusting their calendar compared
> to others... So this all makes "date" a rather strange thingy :-)

1-13 Feb 1918 are omitted from the Russian calendar ?
The delay was mainly due to the orthodox church.

THIS is the main reason I am starting by confirming the accuracy of the
day calculation in DATE. The conversion routines mainly work from Julian
days, but as long as the Gregorian day count is correct, I can convert.
I think that there will probably be a UDF with a lot of the conversions
in, and display functions for chinese, islamic and hebrew dates from the
underlying 'calendar' later.

Lester Caine
L.S.Caine Electronic Services