W3C home > Mailing lists > Public > semantic-web@w3.org > July 2010

Re: Subjects as Literals

From: Hugh Glaser <hg@ecs.soton.ac.uk>
Date: Thu, 1 Jul 2010 14:21:08 +0000
To: Steve Harris <steve.harris@garlik.com>
CC: Ross Singer <rossfsinger@gmail.com>, Robert Sanderson <azaroth42@gmail.com>, Linked Data community <public-lod@w3.org>, Semantic Web <semantic-web@w3.org>
Message-ID: <EMEW3|7264cf05cd3ae1eae723cd5547dfce3am60FLc02hg|ecs.soton.ac.uk|C85262E4.157AF%hg@ecs.soton.ac.uk>
Thanks Steve.
Sort of settles the issue for me.

Yes, I see RDF as simply a graph, and so can't understand why rdfs:label is
any more sensible than rdfs:labels (as an inverse of rdfs:label)- it looks
like a convention on the directed graph to me, and arbitrary.
But as others have pointed out, pragmatism in use is very important.
If the cost is to break things, then it is a Bad Thing to change at this
moment.

So leave as be (but perhaps encourage technology providers to think about
being able to be liberal in accepting literals in subject position, where
possible).

By the way, in answer to questions of how easy it is to use RDF, my
experience is that it is just great for the big bucket of triples
applications that we seem to be using in our system.
That is, as a data interchange format.
Of course, if you actually want to model things, then it gets more
challenging, but then it is expected that it should be.

So it ain't broke enough to make it worth fixing, and there are a whole
bunch of other issues that Dan points out that might be worth thinking about
first.

Cheers
Hugh

On 01/07/2010 11:34, "Steve Harris" <steve.harris@garlik.com> wrote:

> On 2010-07-01, at 03:20, Hugh Glaser wrote:
>> In fact, a question I would like to ask, but suspect that noone who can
>> answer it is still reading this thread ( :-) ):
>> For those who implement RDF stores, do you have to do something special to
>> reject RDF that has literals as subject?
> 
> In my defence, I'm not reading this thread, but someone pointed me at it :)
> 
> Yes, and no. The engine will reject any literals in the subject position, the
> index can't represent that. It's a source of significant optimisations, and we
> would have to do a /lot/ of engineering work to allow them.
> 
> To be brief: I don't care if there are usecases for literals in the subject
> position. It you could rewind time 10 years I might like them in there, but
> we've invested millions of pounds in engineering RDF stores conforming to RDF
> 2004. I can't, and won't throw that work away for some relatively obscure
> benefits.
> 
> - Steve

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Hugh Glaser
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Received on Thursday, 1 July 2010 14:22:12 UTC

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