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RE: XSRQL proposal

From: Seaborne, Andy <andy.seaborne@hp.com>
Date: Mon, 28 Jun 2004 22:18:18 +0100
To: "'Howard Katz'" <howardk@fatdog.com>, <public-rdf-dawg@w3.org>
Message-ID: <000301c45d55$7069ed10$0a01a8c0@atlas>

Howard,

I have got through the XsRQL proposal - nicely written document and I have a
good sense of what XsRQL is and does.  I particularly liked the style except
the yellow (!) ... 

A few "straightforward" questions:

1/ Is the output always syntactic?  Some of the examples are explicitly
creating strings in the query itself.

In RDQL, the output is not defined: indeed, in Jena, the output is a Java
structure with the real RDF Java objects so you can switch between query and
other APIs.  The formatted output shown in the tutorial is based on feeding
queries to a general result as formatter as accessed through the command
line wrapper.  The decision on formatting is not part of the query process
but part of the formatting process.

2/ XsRQL is strong on the construction side of results: how do you see this
working with rules?

3/ The data model has subjects, predicates and objects and the syntax uses
cues to indicate what is a predicate using @.  How do I write a query that
does 

(?x ?x anything)

Which would match the well known "rdf:type rdf:type rdf:Property."  RDF
works on URIrefs rather than types so I wonder if this makes a difference or
not.

[More common would be queries that work on properties and then access any
domain and range constraints use a predicted URI is a property and as a
subject.]

4/ (checking question) In

{ $libby, @newFoaf:Name, $libby/@foaf:name/* }

does the generation create many triples, one for each match of
$libby/@foaf:name/* or a triple with a sequence for the object value?  I
presume it's the former.

5/ Could you add collections to the types?  This seems quite tricky to deal
with in any triple oriented RDF query language.


	Andy


-------- Original Message --------
> From: public-rdf-dawg-request@w3.org <>
> Date: 27 June 2004 21:40
> 
> I've finished my XSRQL proposal, which can be found at
> http://www.fatdog.com/xsrql.html. You'll notice I've shortened the
> acronym slightly: XSRQL stands for XQuery-style RDF Query Language. I
> hope this latest addition to the query-language canon isn't
> considered overly XS-ive (groan).
> 
> I'm slightly embarrassed; I've gone totally overboard on
> this. (If you encounter graffiti in public lavatories
> reading, "Stop me before I write again!", it was probably
> me.) In any event, those who don't have the time or the
> desire to plow through the proposal in its entirety can
> probably get a fairly quick idea of what the language is
> about by reading the introduction [1] and then skipping to
> the section on the path language [2] . You might also find
> the Examples section [3], which looks at several examples of
> code in both RDQL and XSRQL, of interest. Once you've
> recovered from that, you can go back and read the rest at your leisure.
> 
> I'd be honoured if somebody would volunteer to pick this up
> for evaluation before the agenda deadline (July 7?). I'm
> around through this coming Tuesday evening, so if anybody has
> any questions, either get a hold of me before then or after
> I'm back from vacation on the 6th.
> 
> Ta,
> Howard
> 
> [1] http://www.fatdog.com/xsrql.html#Introduction
> 
> [2]  http://www.fatdog.com/xsrql.html#Path%20language
> 
> [3] http://www.fatdog.com/xsrql.html#Examples
Received on Monday, 28 June 2004 17:18:42 GMT

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