RE: RDF in XHTML

Dan Brickley wrote:
>
>
> On Mon, 16 Apr 2001, Murray Altheim wrote:
> >
> > The difficulty with external links is first of all management.
> If you have
> > 1000 documents you'd have 1000 metadata files. It's a lot simpler to add
> > the markup into the document, a lot easier to be sure you've
> got the right
> > metadata, and spiders can obtain the data directly. I also
> think it'll be
> > a lot easier for authors and braindead tools. Documents will also remain
> > rather portable.
>
> It doesn't follow from the use of LINK REL that you have to manage
> metadata on a file-per-document basis. You might point into a CGI or
> servlet (hopefully disguising this to the outside world), or autogenerate
> those files from a database managed elsewhere. I do share your bias
> towards (at least some) embedded metadata though.


The term "validation" used in the strict DTD fashion really works poorly
with RDF. "Schema validation" works a bit better, especially the idea that
the schemata used to (schema) validate a mixed namespace document (such as
XHTML + foo) are referenced by the namespace URI.

This is where RDDL helps. For example suppose the RDF namespace URI where to
reference a RDDL document containing referenced resources for both the RDF
and XML Schemata for RDF (assuming Dan Connolly were to update and complete
his XML Schema for RDF).

A RDDL aware XML Scheme validator would obtain a to be included schema
module for some embedded RDF by reference of the document at the end of the
namespace URI, and hence be able to schema validate an XHTML document with
an embedded <rdf:RDF> chunk.

>
> Yes, pointing to metadata generically isn't so informative. It would be
> nice to have some mechanism for hinting at the sort of thing found at the
> other end... (hmm... doesn't XLink do this for us, allegedly.)
>

That would be the xlink:role, also known as the RDDL "nature" of a related
resource. The xlink:arcrole or RDDL "purpose" describes how a resource is to
be used with respect to a namespace, the nature describes the "sort of
thing" found at the xlink:href.

-Jonathan

Received on Monday, 16 April 2001 22:13:16 UTC