W3C home > Mailing lists > Public > www-rdf-interest@w3.org > May 2002

Re: Innovation, community and queries

From: Patrick Stickler <patrick.stickler@nokia.com>
Date: Thu, 23 May 2002 09:13:43 -0400
To: "ext Seaborne, Andy" <Andy_Seaborne@hplb.hpl.hp.com>, "'Jeen Broekstra'" <jeen.broekstra@aidministrator.nl>, Graham Klyne <GK@ninebynine.org>, Aaron Swartz <me@aaronsw.com>
CC: RDF Interest <www-rdf-interest@w3.org>
Message-ID: <B912634A.153D5%patrick.stickler@nokia.com>

I would like to see a standardized RDF QL *in* RDF. It is hard to
get folks to learn "yet another language" and having a means to
express query-by-example in RDF makes it easier for users who already
are familiar with RDF/XML to use it.

I appreciate that SQL is a well established and widely known query
language, but I see no overwhelming reason why an RDF QL need emulate it.

Attached is an RDF schema and some additional explaination of such
an RDF QL in RDF that I've myself been working on. Comments very welcome.



On 2002-05-23 8:42, "ext Seaborne, Andy" <Andy_Seaborne@hplb.hpl.hp.com>

>> There are several good proposals for QLs out there, and I think
>> that creating a "working draft QL" hybrid of a couple of these
>> would be a seriously good idea.
> This is a good way forward - take the first generation languages and
> consolidate the ideas.
> It would really help toolkit/framework builders, both current ones and
> future ones to have one common QL.  It would help semantic web application
> builders to have a common language they could get to learn.  It would help
> tool builders to be independent of the RDF system they would otherwise need
> to choose.
> Andy 
> -----Original Message-----
> From: Jeen Broekstra [mailto:jeen.broekstra@aidministrator.nl]
> Sent: 23 May 2002 13:15
> To: Graham Klyne; Aaron Swartz
> Cc: www-rdf-interest@w3.org
> Subject: Re: Innovation, community and queries
> Graham,
> On Thursday 23 May 2002 01:40, Graham Klyne wrote:
>> As someone who has recently designed and implemented a (yet
>> another) RDF query "language", I'm not convinced we're ready to
>> standardize. I'm not convinced we know enough about the performance
>> issues in RDF, and I'm also not convinced that standardizing a query
>> language at this time would bring great benefits.  But I could be
>> wrong on both counts.
> A possible benefit I see of standardizing on an RDF QL would be
> to harness efforts made in several groups to optimize tools for
> "their own" QL into a single framework. This makes it much
> easier for such groups to compare results and benefit from each
> other.
> There are several good proposals for QLs out there, and I think
> that creating a "working draft QL" hybrid of a couple of these
> would be a seriously good idea. In fact, we have some plans of
> our own to try this, but we haven't pursued this further sofar,
> because we do not think it is a good idea to propose Yet Another
> RDF QL[tm] on our own.
> As for performance issues, I do not think that should be an
> impediment to standardizing on a language, or at least making a
> "starting effort" to do so. The implementation and storage
> format should be seen as seperate from the QL spec, I think. I
> would say that expressive power and complexity/"learning curve"
> are the most important parameters for any QL.
>> My own intuition is that a query language for RDF should aim to
>> operate at a higher level than "find this pattern of triples", but in
>> my implementation it was hard to break away from.
> I am not quite sure what kind of higher level you have in mind.
> Do you mean something like RDF Schema semantics interpretation,
> or something more along the lines of query formulation in
> natural language?
>> I'd like to see more work on storage formats before we
>> nail down a query language.
> As I said, I think they are seperate issues. I'm hammering this
> because the system I work on (Sesame) operates on the premise
> that storage and retrieval are completely abstract operations.
> The query interpreter does not have knowledge of the storage
> format, nor is the storage format dependent on the QL we use.
> Regards,
> Jeen

Patrick Stickler              Phone: +358 50 483 9453
Senior Research Scientist     Fax:   +358 7180 35409
Nokia Research Center         Email: patrick.stickler@nokia.com

Received on Thursday, 23 May 2002 09:10:44 UTC

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