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Re: [Graphs] Proposal: RDF Datasets

From: Yves Raimond <Yves.Raimond@bbc.co.uk>
Date: Mon, 22 Aug 2011 16:41:51 +0100
To: Pierre-Antoine Champin <pierre-antoine.champin@liris.cnrs.fr>
Cc: Richard Cyganiak <richard@cyganiak.de>, RDF Working Group WG <public-rdf-wg@w3.org>
Message-ID: <20110822154151.GF24767@dvbstreamer.national.core.bbc.co.uk>
On Mon, Aug 22, 2011 at 04:36:43PM +0100, Yves Raimond wrote:
> Hello!
> 
> > As I promissed to Richard during the last TC, I'm reactivating the
> > thread on his proposal to "lift" the definition of RDF datasets into
> > from SPARQL to RDF concepts [1]
> > 
> > My main concern with this proposal is that it defines a somewhat complex
> > structure (the dataset) as a primitive concept in RDF. My gut feeling is
> > that we could instead define more basic concepts, on top of which SPARQL
> > datasets, SPARQL graph stores, and possibly other structures, could be
> > defined. In my understanding, this is what the g-* terminology was
> > aiming at.
> > 
> > In this perspective, back in June, I made an alternate proposal [2] for
> > which I got almost no feedback. In a nutshell, it provides a minimal
> > vocabulary for reifying RDF graphs into standard RDF, and sketches the
> > semantics of such a reification. From there, it illustrates how
> > multi-graphs syntaxes (such as Trig) and models (such as SPARQL
> > datasets) can be defined on top of it.
> > 
> 
> One concern I have with that proposal is that instructions modifying the parsing behavior are embedded within certain URIs (rdf:xml-serialization). Does that mean, when writing an RDF parser, you'd need to manually check for those specific predicates (which would need to be added as soon as there's a new serialisation for RDF ; rdf:jsonld-serialization, rdf:binaryrdf-serialization, rdf:ntriples-utf8-serialization...).

Also, what if a serialisation you support points to a literal in a serialisation you don't support? Or does that mean we need to mandate a set of serialisations all serialisers should support? Or to force a particular serialisation to only point to graphs in that same serialisation?

Best,
y

> 
> Also, the relationship between the holding graphs and the contained graphs would need to be specified exactly - are the prefixes and the base URI shared?
> 
> On a different note, it might be very difficult to read if you have a graph g quoting a graph g2 quoting a graph g3?
> 
> Best,
> y
> 
> > I know that Richard was concerned about several multi-graph models had
> > slight differences (e.g. can a BNode be used as a graph name), and his
> > solution was to endorse one of them and wait for the others to converge.
> > My proposal is rather to provide the building blocks for everyone to
> > describe their model in RDF itself, and leave it open for different
> > models to coexist, which is ok as long as they can all be expressed in
> > plain RDF.
> > 
> >   pa
> > 
> > 
> > [1] http://www.w3.org/2011/rdf-wg/wiki/TF-Graphs/RDF-Datasets-Proposal
> > [2] http://www.w3.org/2011/rdf-wg/wiki/TF-Graphs/RDF-Quadless-Proposal
> > 
Received on Monday, 22 August 2011 15:42:25 GMT

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