I agree with Rod and Gregor that we ought to use full URIs to indicate nomenclatural codes.
Gregor is right that we could use
rdf:resource="&tn;/botanical"
as an abbreviated reference to such a URI, so long as we provide an entity definition for tn in an embedded DTD. If this is done properly, RDF parsers can handle it (because the entity is expanded during XML parsing). However, it's easy to lose the DTD when copying and pasting, when creating your own RDF using someone else's as an example, or when using text processing routines on serialized RDF/XML.
DTDs are defined at the document level while non-anonymous/non-blank RDF resources are global and the full description of a global resource can be split among multiple files. To cut down the likelihood of errors we should probably keep it simple and suggest the use of full URIs as a best practice.
-Steve
Gregor Hagedorn wrote:
Steve writes:
However, using XML namespace prefixes in resource references inside RDF/XML documents tends to cause problems because not all RDF/XML parsers are smart enough to dereference the namespace prefix and build a fully-qualified resource URI. A safer form of the above would be
the fully qualified resource URI which looks like: <tn:nomenclaturalCode rdf:resource="http://tdwg.org/2006/03/12/TaxonNames/botanical" />
It seems the discussion confuses QNames ("namespace-colon") and XML-Entities (ampersand-semicolon) - or am I confused???
An attempt to clarify: From my understanding, xml itself has no such thing as a namespace-colon in literals - xml-schema has introduced it as a convenient thing (QName). However, the use of xml-entities is a requirement of xml 1.0 itself. I agree with Rod that URIs are correct way for RDF:
rdf:resource="http://tdwg.org/2006/03/12/TaxonNames/botanical"
and under no circumstances (even with RDF-xml-Schema) can we use
rdf:resource="tn:/botanical"
because RDF does not use QNames. However, we can use (if abbreviation is an issue, and providing an entity definition for it, as the protege examples do.)
rdf:resource="&tn;/botanical"
If RDF-parsers fail to deal with the latter, they are grossly non-interoperable with xml as a whole.
Gregor---------------------------------------------------------- Gregor Hagedorn (G.Hagedorn@bba.de) Institute for Plant Virology, Microbiology, and Biosafety Federal Research Center for Agriculture and Forestry (BBA) Königin-Luise-Str. 19 Tel: +49-30-8304-2220 14195 Berlin, Germany Fax: +49-30-8304-2203
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