W3C home > Mailing lists > Public > public-rdfa@w3.org > May 2009

Re: RDFa in <head>

From: Kingsley Idehen <kidehen@openlinksw.com>
Date: Tue, 05 May 2009 08:07:50 -0400
Message-ID: <4A002C16.9090207@openlinksw.com>
To: Mark Birbeck <mark.birbeck@webbackplane.com>
CC: Stephane Corlosquet <stephane.corlosquet@deri.org>, RDFa <public-rdf-in-xhtml-tf@w3.org>, public-rdfa@w3.org
Mark Birbeck wrote:
> Hi Stephane,
>> This brings me to the next topic! In RDF, the URI of a resource should be
>> different from the URI of the page that describes it. I've heard this is not
>> so important with RDFa since the RDF is self contained. Is that right?
> I'm not sure what lies behind this point, but if I understand it
> correctly, I'd have to disagree; ultimately the data is RDF, whether
> carried via RDFa, N3, RDF/XML, or whatever. So we still need to solve
> the same problems, and we still need to ensure that there is no
> confusion between items.
>> Crafting a URI for a resource described at http://example.com/node/1 is easy
>> by appending #self, #me or #this, and this can be automated. However in the
>> particular case of a blog post for instance, the page and the resource it
>> describes are in fact the same thing. Shouldn't they have the same URI?
> This is where it starts to get esoteric. :)
> My suggestion would be that Drupal should generate a unique identifier
> on the node itself (using @about) since this will then work in any
> context. For example, if I search for items, then each node in the
> search results would have its own @about value, and so be
> self-contained. Similarly, if I use Views to create some new block or
> something, by having @about on each node, everything 'just works'
> within the block.
> Of course, even in this scenario, you could possibly get away with
> having the same URI for a blog post and the page that carries that
> post, but I'd still advise against it.
> By merging the two URIs you are effectively saying that you don't
> envision a scenario where you would like to say things about a blog
> post, independent of the page that carries the post...and as we know
> in software, never say never.
> A good example of where things can start to break down comes when
> republishing blog posts (or YouTube videos, or Flickr images, etc.)
> from other sites onto your own site; the subject of the post should
> really refer to the original post's location, and not the URL on the
> republishing site.
> In short, I'd say that you can't go wrong if you keep the two
> separate, whilst if you try to cut corners by merging the two URIs,
> you could be storing up problems.

Yes! Identifiers (URIs)  should always be totally independent of factors 
such as location, value, and structure changes :-)

> Regards,
> Mark



Kingsley Idehen	      Weblog: http://www.openlinksw.com/blog/~kidehen
President & CEO 
OpenLink Software     Web: http://www.openlinksw.com
Received on Tuesday, 5 May 2009 12:08:29 UTC

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