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Intro + question

From: Sven Groppe <Sven.Groppe@deri.org>
Date: Wed, 18 Jan 2006 12:33:50 +0100
To: <public-rdf-dawg@w3.org>
Message-ID: <008201c61c23$0df8cc80$380110ac@at.deri.local>

Dear members of the DAWG working group,
I am an employee of the Digital Enterprise Research Institute (DERI), which
has a big focus on the Semantic Web and contributes already to other W3C
working groups like RIF, at the University of Innsbruck.
See below for my business contact.
Originally, I came from the database community. My topic of my Doctorate is
"XML Query Reformulation for XPath, XSLT and XQuery" (ISBN 3-933893-24-0).
I hope I can contribute to the DAWG working group regarding my background
and although the working group seems to be nearly finished.
I have a question concerning the
"SPARQL Query Language for RDF
W3C Working Draft 23 November 2005".
I think it is similar to the remarks of
but I apologize if I oversee further discussions.

I am of the opinion that is important
to support nested queries. Nested queries are important if you want e.g.
support views, which plays is a key point for integrating heterogeneous

I would expect that the production
[9]   DatasetClause   ::=   'FROM' ( DefaultGraphClause | NamedGraphClause )

would allow to query also the result of
a ConstructQuery, i.e. 

[9]   DatasetClause   ::=   'FROM' ( DefaultGraphClause | NamedGraphClause |

Simple Example:

PREFIX foaf:    <http://xmlns.com/foaf/0.1/>
PREFIX vcard:   <http://www.w3.org/2001/vcard-rdf/3.0#>

SELECT ?mbox
	CONSTRUCT   { <http://example.org/person#Alice> vcard:FN ?name }
	WHERE       { ?x foaf:name ?name }
  { ?x foaf:name "Johnny Lee Outlaw" .
    ?x foaf:mbox ?mbox }
Note that this is a simple example and that for other views in real
integration scenarios of course more complicated CONSTRUCT queries would

I apologize again if I oversee something in the specification that allows
some kind of nested queries or if there was a discussion with the decision
not allowing nested queries.
In the latter case, I would be interested in the arguments not to support
nested queries as I cannot imagine reasonable arguments (except
implementation effort).
Dr. Sven Groppe
 University of Innsbruck
 Institute of Computer Science
 Digital Enterprise Research Institute (DERI)
 EMail: Sven.Groppe@deri.org
 Phone: +43 512 507 6424
 Fax:   +43 512 507 9872
Received on Wednesday, 18 January 2006 11:37:25 UTC

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