I guess this is really a question about RDF datatyping but I thought I'd
ask here first....
I've recently been looking at a draft DC application profile which
recommends the use of XML literals as value strings and URIs
corresponding to XML Schema complexTypes as Syntax Encoding Scheme URIs
[1]
(Actually I think the SES URIs refer to the element declarations rather
than the complexType definitions, but I think the intent is to refer to
the complexType?)
Let's leave to one side for a moment the issue of whether this approach
makes the information represented by that XML fragment opaque to an
RDF/DCAM application: XML Literals are still good as value strings in a
DCAM description set.
So my question is about the use of XML Schema complexTypes as Syntax
Encoding Schemes/RDF datatypes. Can I refer to an XML Schema complexType
- assuming I have a URI for it (XML Schema itself uses Qnames to refer
to a datatype, but I can still coin a URI for one) - as an RDF datatype?
Or indeed can I provide any datatype for an XML Literal, other than the
rdf:XMLLiteral datatype? I don't think I'd ever seen a case where an XML
literal was typed with a "more specific" datatype corresponding to an
XML Schema complexType.
As a secondary question, if RDF does permit this, how would I express
this in RDF/XML? In RDF/XML, the use of the rdf:XMLLiteral datatype is
indicated using the rdf:parseType="Literal" attribute, but AFAIK I can't
use rdf:parseType="Literal" and the rdf:datatype attribute on a single
RDF/XML Property Element, or at least the parser won't interpret the
rdf:datatype attribute as a datatype for the literal.
e.g. given
http://www.incognitum.net/petej/projects/xmlliteral/20080425/ex1/
http://www.incognitum.net/petej/projects/xmlliteral/20080425/ex2/
I get the same triples in each case (with a literal object with the
datatype rdf:XMLLiteral)
http://triplr.org/ntriples/www.incognitum.net/petej/projects/xmlliteral/
20080425/ex1/
http://triplr.org/ntriples/www.incognitum.net/petej/projects/xmlliteral/
20080425/ex2/
Pete
[1]
http://www.ukoln.ac.uk/repositories/digirep/index/Geospatial_Application
_Profile
[2] http://www.w3.org/TR/rdf-concepts/#section-XMLLiteral
---
Pete Johnston
Technical Researcher, Eduserv Foundation
Web: http://www.eduserv.org.uk/foundation/people/petejohnston/
Weblog: http://efoundations.typepad.com/efoundations/
Email: [log in to unmask]
Tel: +44 (0)1225 474323
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