- From: Dave Reynolds <der@hplb.hpl.hp.com>
- Date: Thu, 17 May 2001 09:49:39 +0100
- To: Peter Breton <pbreton@MIT.EDU>
- CC: Mick Bass <bass@MIT.EDU>, www-rdf-dspace@w3.org, "Brian McBride (E-mail)" <bwm@hplb.hpl.hp.com>
Peter Breton wrote: > It seems to me that at least part of the problem seems to be that RDF is > format-agnostic (RDF is the same whether it's expressed as triples, in a > visual graph, or in XML serialization -- and there are multiple possible > XML serializations), whereas the intent of OAI is to be directly > parsable and usable. Actually I'm not sure that that is the main problem with RDF in OAI. The problem, as I see it, is that OAI requires not just well-formed XML but XML validatable by a fixed XML-Schema. The whole point of RDF is to be able to combine metadata formats and thus properties drawn from different namespaces can appear in the same set of assertions. So while is it possible to define an XML-Schema for, say, Dublin Core in RDF it is not obvious that you can have a fixed XML-Schema that would validate arbitrary RDF conforming to the M&S spec. It is this flexibility of property name spaces rather than format-agnosticism which I see as the issue. The latter is actually the solution. > Would a specific OAI-blessed canonical XMLserialization fly, d'you think? Exactly. It is perfectly possible to define a simple XML syntax for RDF which is XML-schema validatable, so long as you don't want any deep meaning to the validation (e.g. serialize property names just as text, into attribute values or into element bodies). Both Sergey Melnik and Brian McBride (and probably others) have proposed raw RDF-triple-in-XML syntaxes which either do, or could easily be adapted to, meet this need. It is conceivable that the new W3C RDF Core working group might specify a raw triple syntax which meets the constraints of XML Schema validation. OAI could define/bless such a serialization anyway. Dave
Received on Thursday, 17 May 2001 04:49:42 UTC