From: martinl_at_talk21.com
Date: Mon Feb 26 2001 - 01:44:42 CET
Received: (from mdom_at_localhost) by karto.ethz.ch (8.9.3/8.9.3/SuSE Linux 8.9.3-0.1) id BAA10826 for cavexml-outgoing; Mon, 26 Feb 2001 01:47:26 +0100 Received: from t21mta00-app.talk21.com (mta00.talk21.com [62.172.192.40]) by karto.ethz.ch (8.9.3/8.9.3/SuSE Linux 8.9.3-0.1) with ESMTP id BAA10822 for <cavexml_at_cartography.ch>; Mon, 26 Feb 2001 01:47:24 +0100 From: martinl_at_talk21.com Received: from t21mtaV-lrs ([10.216.84.21]) by t21mta00-app.talk21.com (InterMail vM.4.01.02.27 201-229-119-110) with SMTP id <20010226004506.OLTK20466.t21mta00-app.talk21.com_at_t21mtaV-lrs>; Mon, 26 Feb 2001 00:45:06 +0000 X-Mailer: talk21 v1.17 - http://www.talk21.com To: cavexml_at_cartography.ch, cavexml_at_cartography.ch X-Talk21Ref: none Date: Mon, 26 Feb 2001 00:44:42 GMT Subject: Re: Dates: explicit fields and missing values Content-type: text/plain; charset="ISO-8859-1" Message-Id: <20010226004506.OLTK20466.t21mta00-app.talk21.com@t21mtaV-lrs> Content-Transfer-Encoding: 8bit X-MIME-Autoconverted: from quoted-printable to 8bit by karto.ethz.ch id BAA10823 Sender: owner-cavexml_at_karto.baug.ethz.ch Precedence: bulk Reply-To: cavexml_at_cartography.ch
XML schema defines a builtin datatype of "date" as a timePeriod of 1 day from midnight, expressed in one of the ISO 8601 formats: CCYY-MM-DD (the hyphens seem to be required, the calendar is Gregorian). This can be extended to the right to specify hours and minutes or truncated to the left to represent year and month or just year. The reference is http://www.w3.org/TR/xmlschema-2/#date.
> 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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