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RE: Supplemental XQuery reading list

From: Howard Katz <howardk@fatdog.com>
Date: Fri, 16 Apr 2004 07:54:06 -0700
To: "Eric Prud'hommeaux" <eric@w3.org>
Cc: "RDF Data Access Working Group" <public-rdf-dawg@w3.org>
Message-ID: <IKEOLCDFPBBPPAHGNKKOCEIFEKAA.howardk@fatdog.com>


> I can't speak to Andy's agenda, but one point that's been kicking
> around in the XQuery/RDF Query arena for a while is that XQuery can be
> used to express SQL queries so it must be able to express RDF
> queries.

It can, if you're able to work out a mapping from the RDF data model into
the XQuery data model, which is basically the XML Infoset + XML Schema
support + support for multiple documents.

I'm finding myself quite interested in the inverse problem: would it be
possible and useful to be able to map from the XQuery surface language into
an underlying RDF graph-based data model, so that XQuery syntax can be used
to interrogate an RDF data store more or less directly? In other words, can
we swap out XQuery's underlying XML-based data model and slide in an
RDF-based one in its place so that we don't have to do the mapping to XML?
I'll be talking about this after Amsterdam.

> I've seen a couple approaches that I believe workable [1]
> [2], but would like to see how people solve the problem for SQL.

I've given a few pointers in my response to Andy's email re SQL-to-XML
mappings for XQuery.

> I suspect that in standardizing an RDF query language we are going
> beyond where existing SQL mappings to XQuery have gone in that we want
> *one* mapping to XQuery that operates on XQuery+whatever
> implementations from different vendors. Does such a "standard" mapping
> to SQL exist?

I'm not sure what you mean by the last, Eric. Can you explain a bit more?

Howard

> [1] http://www.w3.org/2001/11/13-RDF-Query-Rules/#XQueryFA
> [2] http://www.w3.org/2001/11/13-RDF-Query-Rules/#TreeHugger
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Received on Friday, 16 April 2004 10:52:56 GMT

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