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Re: XQuery syntax for BRQL semantics

From: Dan Connolly <connolly@w3.org>
Date: Tue, 07 Sep 2004 08:07:35 -0500
To: Rob Shearer <Rob.Shearer@networkinference.com>
Cc: RDF Data Access Working Group <public-rdf-dawg@w3.org>
Message-Id: <1094562455.6086.168.camel@dirk>

On Sun, 2004-09-05 at 23:15, Rob Shearer wrote:
[...]
> I propose that we adopt a syntax
> which is fully compatible with XQuery, in that every DAWG query is in
> fact a valid XQuery.

I managed to read thru this once, somewhat carefully but pretty
quickly, and it looks like a pretty complete proposal.

I see just a couple points that look significantly
different from BRQL, other than surface syntax and
the omission of optionals that you discussed...


> XQuery syntax makes it quite straightforward to add as much, or as
> little, structure as you like to a result:
> 
> for $x in dawg:anything(), $name in dawg:anything() $mbox in
> dawg:anything()
> where dawg:related($x, foaf:name, $name)
>   and dawg:related($x, foaf:box, $mbox)
> return <x><name>{$name}</name><mbox>{$mbox}</mbox></x>
> 
> <x><name>Johnny Lee
> Outlaw</name><mbox>mailto:jlow@example.com</mbox></x>
> <x><name>Peter Goodguy</name><mbox>mailto:peter@example.org</mbox></x>


That's a significant difference. BRQL queries return
binding sets or graphs; handling arbitrary XQuery data
models is different.

And how does this proposal handle returning graph
results? I suppose another function to go with
dawg:anything() to return the original graph would
do it.


-- 
Dan Connolly, W3C http://www.w3.org/People/Connolly/
Received on Tuesday, 7 September 2004 13:07:27 GMT

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