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Re: RDF/XML and named graphs

From: Story Henry <henry.story@bblfish.net>
Date: Wed, 19 Dec 2007 13:17:35 -0200
Cc: Richard Cyganiak <richard@cyganiak.de>, Chris Richard <chris.richard@gmail.com>, Steffen Staab <staab@uni-koblenz.de>, Peter Ansell <ansell.peter@gmail.com>, Fabien Gandon <Fabien.Gandon@sophia.inria.fr>, p.roe@qut.edu.au, j.hogan@qut.edu.au, Semantic Web <semantic-web@w3.org>
Message-Id: <A3191E10-B9D9-481F-A4DE-3EC411E237F4@bblfish.net>
To: Jeremy Carroll <jjc@hpl.hp.com>
I would always recommend people learn N3 first.

But I would not completely condemn RDF/XML . XML is a very powerful  
format. And RDF/XML has a lot of interesting advantages . You can use  
the XML tools with it for example, if you provide what I call a  
crystallisation of the RDF graph [1]

My feeling is that RDF/XML is very close to being a good format, but  
that perhaps as more people start getting into RDF, via N3, at some  
point we will have enough knowledgeable people on both the RDF and the  
XML side of the fence that a breakthrough solution will be found.

Henry

[1] http://blogs.sun.com/bblfish/entry/crystalizing_rdf

On 19 Dec 2007, at 13:05, Jeremy Carroll wrote:

>
> Richard Cyganiak wrote:
>> In every other regard, RDF/XML is a complete and utter train wreck.  
>> Adding named graph support to RDF/XML would be polishing a turd.
>
> I used to think this, but have been slowly coming round to seeing  
> some of the advantages of RDF/XML ....
>
> To engage in self quotation, from:
>
> http://www.hpl.hp.com/techreports/2004/HPL-2004-56.pdf
> (Carroll + Stickler, p6)
>
> What's Right With RDF/XML?
>
> Given the number of suggestions for change and RDF/XML's lack of  
> popularity with the practioners, why does it continue?
> Once you get used to it, it is surprisingly concise. The RDF data  
> model, in which everything is triples, is inevitable verbose - but  
> writing these triples in RDF/XML tends to ameliorate things.
>
> The use of qnames to abbreviate URI references is concise, and  
> sufficiently liked that this convention is widely used, also in non- 
> XML contexts, e.g. in N3 [N3], and the OWL Semantics [OWL S&AS]  
> document. The use of typed nodes, to avoid making a common triple  
> explicit, adds to the efficiency with which RDF/XML encodes the RDF  
> graph, and permits syntaxes which, to some extent, hide the  
> underlying triple structure.
>
> This hiding of the triple structure makes it easy for users to get  
> into an RDF application such as OWL with only a partial  
> understanding of its representation in RDF.
> However, RDF/XML neithers permits complete hiding of the underlying  
> RDF, nor does it make it clear what that underlying RDF is. We  
> suggest that it is better to have clarity in the basic syntax, with  
> hiding achieved by using alternative syntactic forms that are  
> transformed into the basic syntax.
> RDF/XML also provides a number of syntactic features which are  
> useful for certain sorts of construct:
>   rdf:parseType="Literal" is the only sensible way of embedding XML  
> into the RDF graph. (The alternative requires knowledge of Exclusive  
> XML
> Canonicalization [Excl XML C14N]).
>   rdf:parseType="Collection" is useful when writing OWL Ontologies  
> [OWL
> Ref].
>   rdf:parseType="Resource" is used extensively in XMP [XMP].
>   The use of property attributes is useful when embedding RDF in  
> HTML.
>
> Thus many communities find that while RDF/XML has many features they  
> do not like, certain key features are highly attractive and keep  
> them enagaged.
>
>
> =====
>
> If you want concise compact XML (if that isn't a contradiction),  
> with the extensibility of RDF, then actually working from, rather  
> than against RDF/XML is not an appalling idea.
>
> Jeremy
>
>



Received on Wednesday, 19 December 2007 15:41:05 GMT

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