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Re: Serializing datetime

From: David Booth <david@dbooth.org>
Date: Tue, 31 Jul 2012 12:06:56 -0400
To: Andy Seaborne <andy.seaborne@epimorphics.com>
Cc: public-rdf-dawg-comments <public-rdf-dawg-comments@w3.org>
Message-ID: <1343750816.2725.73576.camel@dbooth-laptop>
Hi Andy,

I am satisfied with this resolution provided that "Advice on canonical
datetime values" is added to the wish list for consideration in the next

It certainly is possible to convert, but one important point of
standardization is to reduce the amount of conversion that is needed
when transferring data from one system to another.


On Tue, 2012-07-31 at 09:05 +0100, Andy Seaborne wrote:
> David,
> Thank you for your comment on serializing datetime values.
> As noted in the response to your comment on "Serializing xsd:decimal, 
> xsd:float, xsd:double", SPARQL reuses the body of work for XSD and 
> XQuery/XPath functions and operators.  The rules for operations on 
> datetimes derive from that work and this includes comparing datetime 
> values.  Support is also now to be found in many programming languages.
> An implementation is free to provide custom function that converts 
> between timezones; XQuery/XPath does not itself provide such a function.
> The working group is not planning to make any changes in this area.
> I would be grateful if you reply to this message to confirm that the 
> working group has responded to your comment.
> Yours, on behalf of the SPARQL Working Group,
>      Andy
> On 20/07/12 16:21, David Booth wrote:
> > I have also noticed that it is a hassle trying to compare datetime
> > values from two different SPARQL servers, because the same datetime may
> > be written with different timezone offsets.  This is less vexing than
> > xsd:decimal serializations, because at least timezone offsets are
> > information preserving, but still it makes comparisons more difficult
> > than they otherwise need to be.
> >
> > I think the WG should consider defining a default datetime format (such
> > as UTC or zero timezone offset) that SHOULD be use, while allowing
> > servers to make this a configurable option.
> >
> > I assume it is too late in the WG process to consider this for SPARQL
> > 1.1, so please add this to the wish list for the next version.
> >
> > Thanks!
> >

David Booth, Ph.D.

Opinions expressed herein are those of the author and do not necessarily
reflect those of his employer.
Received on Tuesday, 31 July 2012 16:07:29 UTC

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