Re: does RDF require understanding all 82 URI schemes?

Dave Beckett writes:

 > I feel it might be needed for serialisation of the RDF graph to
 > RDF/XML, but I haven't implemented that yet.

Unfortunately, the serialization of an RDF graph is impossible in the
general case: the XML Namespaces spec describes two-part names, but
RDF treats them as single part names, and the act of combining the two
is lossy.  Consider:

  <rdf:Description rdf:about="urn:xxx:001" xmlns:foo="">

The RDF data model sees the triple

How can you serialize that back to XML?  This isn't an abstract
problem; the Namespace for the XML Schema datatyping is

and the Namespace for the magic "xml" prefix is

That means that the data type for a decimal number in RDF's view is

and xml:lang in RDF's view is

Ouch!  Fortunately, neither of these is likely to be used as a
property name, but other similar ones likely will be.  We can
hard-code some into RDF processors, but in the general case, we have a
very bad mess on our hands.

All the best,


David Megginson       

Received on Thursday, 8 February 2001 12:56:58 UTC