- From: Dave Beckett <dave.beckett@bristol.ac.uk>
- Date: Thu, 07 Feb 2002 17:11:14 +0000
- To: Pat Hayes <phayes@ai.uwf.edu>
- cc: w3c-rdfcore-wg@w3.org
>>>Pat Hayes said: > Dave said: > >5. DCMI expects xml:lang attribute to be allowed on XML > > <dc:title xml:lang="en">title of thing</dc:title> > > > >and the DCMI community wants to be able to get at that language value > >somehow. I strongly support this. > > > >I have been asked by some people in DCMI community how RDF models > >this and could not give an answer. > > Dave, this keeps coming up and I would like to tackle it, but Im not > sure how, or even if, this XML feature is supposed to map into RDF > triples. If the answer is obvious to you, could you briefly explain > it, using Ntriples? Some answers I see are: 1 N-Triples (current version) <thing> dc:title "title of thing" . Loses the language; but there might be an application-specific method on the model that returned the language string. However, this is old RDF M&S territory and if it isn't in the model, how can it be interoperable? 2 Ntriples+ (with lang-strings): <thing> dc:title "title of thing"(en) . See Jeremy and Bill deHora's analysis: http://lists.w3.org/Archives/Public/w3c-rdfcore-wg/2001Sep/0341.html but it does seem awfully tricky and a bit ugly adding another pair where there used to be a Unicode string. Maybe the proper expansion (to 3 triples with a bnode) is what we will have to recommend, and deprecate the method above <dc:title xml:lang="en">title of thing</dc:title> in favour of <dc:title xml:lang="en" rdf:value="title of thing"/> which generates the 3 Ntriples by using an abbreviated syntax form: <thing> dc:title _:a . _:a xml:lang "en" . _:a rdf:value "title of thing" . Howver that will be a *very* hard sell to the DC community. i.e without language <dc:title>title of thing</dc:title> and with: <dc:title xml:lang="en" rdf:value="title of thing"/> will be hard to explain > >6. The DCMI has the idea of "encoding schemes" for expanding on the > >value of the simple string valued property like above. This is the > >closest thing to data types here. > > > >In the Qualified DC in RDF/XML document above, it is recommended to > >model like this (If I understand it correctly). > > > ><dc:subject> > > <rdf:Description> > > <rdf:value>19D10</rdf:value> > > <rdfs:label>Algebraic K-Theory of spaces</rdfs:label> > > <rdfs:isDefinedBy rdf:resource="URI2"/> > > </rdf:Description> > ></dc:subject> > > > >The rdfs:isDefinedBy might point to any relevant URI2 that defines > >the encoding - such as a term in a controlled vocabulary; this would > >not be to an RDF(s) document. > > > >Optionally an rdf:type might also be used to point to a node of type > >rdfs:Class in an rdf schema if such existed. > > > >The rdf:value isn't required to point to a literal; it might point to > >another blank node with another rdf:value, rdfs:label > > Hmm, thats an interesting idea. What would rdf:value mean if it wasnt > pointing to a literal? For example what relationship between _:x and > _:y would this state: > _:x rdf:value _:y . > _:y rdf:value "10" . The DC idea being referred to here was historically labelled "dumbing down". This was for DC applications just looking for literals about a resource (node) for some purpose, they follow the rdf:value arcs until they get a string, and use that. It is a flattening algorithm for all the properties of a resource. See 3.2 of http://dublincore.org/documents/2001/11/30/dcq-rdf-xml/ Dave
Received on Thursday, 7 February 2002 12:11:17 UTC