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Re: Introducing myself - SOA organised with RDF

From: Richard Newman <r.newman@reading.ac.uk>
Date: Wed, 22 Aug 2007 15:56:16 -0700
Message-Id: <21035766-7828-408C-8343-38B3F690B4B5@reading.ac.uk>
Cc: semantic-web@w3.org
To: Frank Carvalho <dko4342@vip.cybercity.dk>

> What do you mean when you say "tree serialization", BTW? The only  
> serialization I work with
> is a large set of triples.

(I see from other email that you already normalize your data, but I  
already had this written.)

There are multiple possible serializations in RDF/XML of an RDF  
graph. (In fact, some RDF graphs can't be serialized in RDF/XML.)

For example, the triples

   ex:foo ex:bar "baz" .
   ex:foo rdf:type ex:Thing.

can be serialized as

   <RDF xmlns:ex="http://ex/" xmlns="http://www.w3.org/1999/02/22-rdf- 
syntax-ns#">
     <ex:Thing resource="http://ex/foo" ex:bar="baz"/>
   </RDF>

or as

   <rdf:RDF xmlns:rdf="http://www.w3.org/1999/02/22-rdf-syntax-ns#">
     <rdf:Description rdf:about="http://ex/foo">
       <ex:bar>baz</ex:bar>
       <rdf:type rdf:resource="http://ex/Thing"/>
     </rdf:Description>
   </rdf:RDF>

... or in a few other ways.

Now, what XSLT will you use to get the type of ex:foo, or the value  
of ex:bar?

Using XML tools on RDF/XML will require you to either normalize your  
representation, or write convoluted queries to handle RDF/XML's many  
possible appearances. If you're normalizing down into triple-level  
chunks, why not use a real triple store?

>>   cwm is not really designed for large-scale storage.
>
> No, I kind of suspected that from it's behaviour. It's really a  
> shame. It
> was descibed as a sort of RDF swiss army knife, and on small graphs  
> it seems
> to be able to merge graphs nicely. But when I started to load large  
> graphs,
> it came up with odd errors.

Yup, Swiss Army knife, not chainsaw :D

-R
Received on Wednesday, 22 August 2007 22:56:28 GMT

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