From: Peter MATTHEWS (matthews_at_melbpc.org.au)
Date: Sat Feb 24 2001 - 01:26:23 CET
Received: (from mdom_at_localhost) by karto.ethz.ch (8.9.3/8.9.3/SuSE Linux 8.9.3-0.1) id BAA01391 for cavexml-outgoing; Sat, 24 Feb 2001 01:26:24 +0100 Received: from newemu.melbpc.org.au (newemu.melbpc.org.au [203.12.152.25]) by karto.ethz.ch (8.9.3/8.9.3/SuSE Linux 8.9.3-0.1) with ESMTP id BAA01387 for <cavexml_at_cartography.ch>; Sat, 24 Feb 2001 01:26:22 +0100 Received: from peter (a1-32.melbpc.org.au [203.12.158.32]) by newemu.melbpc.org.au (8.9.3+Sun/8.9.3) with SMTP id LAA07044 for <cavexml_at_cartography.ch>; Sat, 24 Feb 2001 11:25:37 +1100 (EST) Message-Id: <3.0.6.32.20010224112623.0083a990@popa.melbpc.org.au> X-Sender: matthews_at_popa.melbpc.org.au X-Mailer: QUALCOMM Windows Eudora Light Version 3.0.6 (32) Date: Sat, 24 Feb 2001 11:26:23 +1100 To: cavexml_at_cartography.ch From: Peter MATTHEWS <matthews_at_melbpc.org.au> Subject: Re: Dates: explicit fields and missing values In-Reply-To: <Pine.GSO.4.05.10102221702170.16386-100000_at_cor.oz.cc.utah.e du> Content-Type: text/plain; charset="us-ascii" Sender: owner-cavexml_at_karto.baug.ethz.ch Precedence: bulk Reply-To: cavexml_at_cartography.ch
One of the main reasons I have preferred split-up dates in my database work
is that sometimes you don't know all the components of the date, especially
with old data, e.g. sometimes you only know the year, or the year and
month. Obviously these would fail a "date" field validity test, so you
would have to leave such a field empty. By splitting it you can just fill
in as much as you know, then format it sensibly during presentation. Or if
day, month and year *have* been filled in, then a routine algorithm can
check their validity.
Re presentation, ISO has an international standard on date formats (sorry,
can't find its actual number just at the moment), so we should pick
format(s) from their range.
Peter Matthews
At 17:13 22-02-2001 -0700, John Halleck wrote:
>> From: Michael Lake <mikel_at_speleonics.com.au>
>> To: cavexml_at_cartography.ch
>> Subject: Re: Dates: explicit fields and missing values
>>
>> Paul & Eleanor wrote:
>> > to his own format. Month followed by day is the American format (but
>> > Anyway, You should be able to detect a non-conforming format quick
>> > enough as soon as someone surveys on a day of the month past the
>> > 12th. :-)
>
>> Yes if its written as 14-12-2001 we know that it must be dd-mm-yyyy but
>
>> Date: 07-11-2001
>
>> 7th day of November or the 11th day of July?
>
>
>> You cannot detect a non-conforming format all of the time.
>> QED. :-)
>
>
>> Conclusion: we have to split the dd, mm and yyyy into either attributes
>> of a date element or split then into individual elements. I'd go for
>> attributes.
>
> I don't think the conclusion is warrented.
> We can define attributes to suit, and we could claim an attribute
> "data" to always be in ISO date format.
>
>> <DATES><surveyDate year="1974" />
>> <creationDate year="1998" month="01" day="10" />
>> <modificationDate year="1999" month="06" day="22" />
>> </DATES>
>
><Survey>
> <Creation date="1998-01-10" who="Nahaj G. Burynag" />
> <Modification date="1999-06-22" who="Edsel J Murphy" />
></Survey>
>
>> Mike
>
>> --
>
>
>
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