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The metamodel thread (was: Re: [dcat] Tomorrow's dcat Agenda)

From: Richard Cyganiak <richard@cyganiak.de>
Date: Thu, 22 Apr 2010 21:30:54 +0100
Cc: Cory Casanave <cory-c@modeldriven.com>, public-egov-ig@w3.org
Message-Id: <63AC08B9-F09E-42D5-8470-0E60804CF2F8@cyganiak.de>
To: Erik Wilde <dret@berkeley.edu>
Erik,

Interesting discussion -- you made some good points, BUT...

On 22 Apr 2010, at 19:13, Erik Wilde wrote:
> In XML, you can see three levels:
>
> - individual nodes in the XML tree (elements, attributes, ...)
> - the XML document (which can be tiny or huge)
> - the set of all XML documents connected by links
>
> in RDF, there are two levels:
>
> - triples
> - the graph of all the triples you know of.

This is correct when you just consider what's said in the 2004 RDF  
specs.

The missing additional level has been recognized as a major problem of  
RDF many years ago. A *lot* of effort went into addressing that -- the  
whole httpRange-14 debate, the work of the Named Graphs crew, the LOD  
practices.

When people in 2010 talk about RDF on the Web, you can pretty much  
take it for granted that they silently assume the “named graphs” data  
model, where graph names correspond to the URLs of RDF documents.

The RDF specs haven't quite caught up with reality and common practice  
yet.

Best,
Richard



>
> another important difference is that in REST, the most important  
> concept is that of a resource which has a URI because then it is  
> possible to link to this URI and interact with the resource using  
> the uniform interface. in semweb, the most important concept is that  
> a resource has a URI because then it is possible to describe the  
> resource by making assertions about that URI, instead of interacting  
> with it.
>
>> But, every solution has issues it is just a matter of which one(s) we
>> are going to vest in so that we don't have the information  
>> fragmentation
>> problems we do now.  Of course we can always invent new ones, but  
>> people
>> are getting tired of that.
>
> yes, and what i wanted to do was to point out the differences  
> between the architectural style of REST, and that of semweb. they  
> are not the same (one focuses on interactions *with* resources, the  
> other on description *of* resources) and both have advantages and  
> disadvantages for certain use cases, exactly like you say.
>
> cheers,
>
> dret.
Received on Thursday, 22 April 2010 20:31:29 GMT

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