Re: on independence of elements, relating versions [XMLVersioning-41]

Dan Connolly writes:

> It occurred to me that in a way, RDF/XML syntax takes
> the principle of independence of elements to an
> extreme.

Indeed, but I think it's important to realize that this approach is just 
what you say: an XML syntax for another (I.e. RDF)  model.  I agree that 
the RDF model has many desirable characteristics, including at least 
several that make it an interesting basis for negotiating interoperation 
between software written at different times and to different assumptions 
(I.e. for tackling the versioning problem.)  I would agree that it 
potentially is a richer and more promising starting point than XML trees 
and XML schema.

On the other hand, I remain unconvinced that XML tools are usually the 
right prism through which to view such a serialized RDF document. Consider 
a document containing the serialization of an RDF triple that expresses 
[Noah(known by his URI), isAuthorOf, Document(known by its URI)].  While 
you can use XPath,  XSL and or XQuery on the XML serialization, it's not 
clear to me that this is the architecturally robust way to extract the 
author for the document.  It seems that if the data is fundamentally RDF, 
you usually want a query mechanism that's aware of RDF and triples. 
Similarly, I don't think that XML schema (or WSDL) would be a first class 
way of enforcing the rule that every such document must have a statement 
of authorship.  It seems to me that using XML tools on such RDF 
serializations is about like using Grep on XML documents;  both are useful 
tricks at times, but Grep is not usually the right way to extract 
information from an XML document and XML tools are not RDF tools. 

As some of you have probably heard me state too often:  it's exactly this 
tension between two interesting architectures, both of which we are 
promoting to our users at about the same time, that most concerns me about 
the coexistence between XML and RDF.  Still, I agree that it's interesting 
to look at RDF in our discussions of XML versioning.  Maybe there's 
something we can indeed apply.

Noah Mendelsohn 
IBM Corporation
One Rogers Street
Cambridge, MA 02142

Received on Wednesday, 17 March 2004 19:36:19 UTC