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Re: RDF 2.0 Wishlist - Legal RDF which I can't SPARQL

From: Mischa Tuffield <mischa.tuffield@garlik.com>
Date: Thu, 29 Jul 2010 17:38:34 +0100
Cc: Damian Steer <pldms@mac.com>, Semantic Web <semantic-web@w3.org>
Message-Id: <7EA65061-099B-40D8-A38F-05DD9070B4A3@garlik.com>
To: Paul Gearon <gearon@ieee.org>
<snip/>
On 29 Jul 2010, at 15:25, Paul Gearon wrote:

> On Thu, Jul 29, 2010 at 10:05 AM, Mischa Tuffield
> <mischa.tuffield@garlik.com> wrote:
>> Do you think that the same logic should be applied to rdfxml too ? Otherwise
>> there will be things you can write in turtle and not in rdfxml which you can
>> subsequently sparql, which simply doesn't feel right to me.
>> I wonder if I should contact the current sparql working group, as they are
>> currently active, and see how they respond. I think it is unfortunate that
>> you can write valid rdf which can't be queried in sparql.
> 
> <snip/>
> 
> Well it's reasonably well known that it's possible to write N3 that
> can't be encoded in RDF/XML, and that doesn't seem to have caused
> great stress until now. Personally, I *much* prefer N3, so it doesn't
> bother me what RDF/XML can't do.  :-)

Sure, I too much prefer turtle to rdf/xml, way easier ... But I guess I am a slave to the tools I use, and as a result n3 isn't an option for me. 

> 
> As for being queried in SPARQL, that's a relative concept. Yes, you
> can't match it directly, as you've pointed out, but it can still be
> returned in results (unless an implementation specifically tries to
> put the data into an internal IRI and a validation error occurs, but
> that's implementation specific). It's always possible to bind it to a
> variable and return the data. Alternatively, if you really did want to
> search for it, you could bind to a variable, and FILTER on its string
> representation. Yes, it will be slow, but my point is that the
> language isn't *completely* deficient (complain to Steve if it is).
> ;-)

I understand that I can query the RDF using sparql and I can bind it to a variable to get the URI returned. I stumbled upon this because I was doing a "insert data {graph <http://example.com/graph> { , <http://example.com/foo'bar> foo:Property "something" . }" as per the sparql update work, which I can't really do the bind trick with, but I didn't want to use that as an example as the sparql people are not finished with their work.

But yes point taken, I have already moaned about this with Steve (and trust me I do bug him the whole time), I guess I will probably end up poking the sparql wg about this. 

Cheers,

Mischa

> 
> Regards,
> Paul Gearon

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Mischa Tuffield PhD
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Received on Thursday, 29 July 2010 16:39:09 UTC

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