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Re: RDF-ISSUE-25 (Deprecate Reification): Should we deprecate (RDF 2004) reification? [Cleanup tasks]

From: Richard Cyganiak <richard@cyganiak.de>
Date: Fri, 8 Apr 2011 11:02:00 +0100
Cc: Ivan Herman <ivan@w3.org>, Eric Prud'hommeaux <eric@w3.org>, David Wood <dpw@talis.com>, RDF Working Group WG <public-rdf-wg@w3.org>
Message-Id: <B913A241-E964-4130-8990-B9EE916E0984@cyganiak.de>
To: Sandro Hawke <sandro@w3.org>
On 8 Apr 2011, at 05:42, Sandro Hawke wrote:
> <u1> { <a> <b> 1, 2 }
> <u2> { <a> <c> 3, 4 }
> 
> would be:
> 
> <u1> eg:hasTriple [ rdf:subject <a>; rdf:predicate <b>; rdf:object 1 ],
>                  [ rdf:subject <a>; rdf:predicate <b>; rdf:object 2 ].
> 
> <u2> eg:hasTriple [ rdf:subject <a>; rdf:predicate <c>; rdf:object 3 ],
>                  [ rdf:subject <a>; rdf:predicate <c>; rdf:object 4 ].
> 
> So, why do SPARQL folks prefer TriG and N-Quads to these forms?  I don't
> know.    

The second is about five times more verbose. It is unsuitable for hand-writing. To be even remotely readable and efficiently processable, it relies on something that is not significant in RDF: order of statements. It is brittle because it raises the question of what to do with incomplete reified triples. Its verbosity explodes exponentially when one wants to say that Alice said that Bob said that Charlie said something.

> If you put that into N-Triples and sort it by predicate, performing the import is going to
> require holding the entire structure in memory.  But a valid response might be, "don't do that".

"Don't do that" is not a practical response. The order of statements is not significant in RDF, and not maintained by many systems.

Richard
Received on Friday, 8 April 2011 10:02:30 GMT

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