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RE: Requirement: queries written as RDF

From: Howard Katz <howardk@fatdog.com>
Date: Thu, 8 Apr 2004 07:14:13 -0700
To: "Dirk Colaert" <Dirk.Colaert@quadrat.be>, "Eric Prud'hommeaux" <eric@w3.org>
Cc: "Rob Shearer" <Rob.Shearer@networkinference.com>, <public-rdf-dawg@w3.org>
Message-ID: <IKEOLCDFPBBPPAHGNKKOOEBCEKAA.howardk@fatdog.com>


> >(2) If queries are represented in XML they can be treated as data
> > and you can run XQueries over a collection of XQueries.
>
> That's interesting. A Query expressed in RDF could be treated as RDF. It
> would be easy to do queries about queries. That's an argument for
> using RDF
> (or a subset, or a convertible format).
>
> All we have to do know is find a use case justifying this
> requirement... :-)

It does sound wonderful, doesn't it? I too would like to know what you would
want to query in a query. Examples anyone ... ?

>
> Or do we have a solution without a problem?
>
> Dirk
>
> -----Original Message-----
> From: Howard Katz [mailto:howardk@fatdog.com]
> Sent: mercredi 7 avril 2004 7:08
> To: Eric Prud'hommeaux
> Cc: Rob Shearer; public-rdf-dawg@w3.org
> Subject: RE: Requirement: queries written as RDF
>
>
> I got several responses back from members of the Query wg on the XQueryX
> question. I particularly liked this one. I don't know if it'll shed any
> light on our own issues, but it's delightfully clear and succinct. The
> author prefers to remain anonymous.
>
> In response to a question on why XQueryX:
>
> > (1) An XML-based syntax was considered easier for machines to
> > generate and exchange than a human-oriented syntax that would
> > require some sophisticated parsing.
> > (2) If queries are represented in XML they can be treated as data
> > and you can run XQueries over a collection of XQueries.
> > (3) Since XML is known to be an answer to all questions, it must be
> > an answer to the question "What would be a good format for expressing
> > queries over XML data"?
>
> In response to a question on the technical difficulties that
> arose once the
> requirement was formulated:
>
> > Once the requirement for an XML query syntax was adopted,
> > arguments immediately broke out over the level of detail at
> which a query
> > should be broken down into XML elements. The working group
> finally settled
> > on two separate approaches that represent extreme points on the
> spectrum:
> > (a) The whole query is wrapped in a <query> element, and otherwise
> unchanged.
> > This approach obviously does not take the XML syntax requirement very
> seriously.
> > (b) The query is parsed, and each and every node in the parse tree
> (including individual
> > operators, function calls, steps in path expressions, etc.) is
> represented
> by its own
> > element, thus making the query incredibly verbose. This format is
> obviously useless to humans.
>
> > At various times and places, people have attempted to define some
> intermediate point
> > between these two extremes. These attempts have always ended in
> rancor and
> controversy.
>
> Finally, in a follow-up clarification:
>
> > I believe that the editor of the XQueryX specification is currently
> pursuing both approaches
> > (a) minimal expansion and (b) maximal expansion. Both will be defined as
> valid forms of
> > XQueryX.
>
> Just to close on a personal note, I've always felt that XML is
> the answer to
> all questions. I'm now coming to feel increasingly that RDF is
> even more so!
>
> Howard
>
> > > On Sun, Apr 04, 2004 at 09:23:14AM -0700, Howard Katz wrote:
> >
> >    [snip ...]
> >
> > > > I certainly agree with the sentiments of the second, "human
> readable"
> > > > requirement. Interestingly enough, the third, "XML" requirement
> > > has been the
> > > > one that's caused the group the most difficulty to my
> > > knowledge, and at the
> > > > moment conformance with this requirement has been downgraded to
> > > optional. I
> > > > don't know what the major issues have been, but it might be
> > > interesting to
> > > > know, if only for the sake of curiosity.
> > >
> > > Can we go beyond the meta-lesson of "that may be hard. it's been hard
> > > in XQuery" to some of the particular problems that requirement caused
> > > the XQuery WG? Also, was this requirement born of some compelling use
> > > cases, or a general notion that it's good practice to express anything
> > > in XML?
> >
> > I wasn't trying to impart a particular lesson. My intention, not knowing
> > what DAWG members know or don't know about it, was simply to
> > provide data on
> > the experience of the Query wg in the event that might prove
> useful to the
> > group. In response to your questions, I've asked several
> members of the wg
> > about their XQueryX experience. If they see fit to pass that on
> > to me, I'll
> > be happy to share it with the group.
> >
> > Howard
> >
Received on Thursday, 8 April 2004 10:13:13 GMT

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