- From: Sergey Melnik <melnik@db.stanford.edu>
- Date: Tue, 04 Dec 2001 14:28:29 -0800
- To: Graham Klyne <GK@NineByNine.org>
- CC: RDF core WG <w3c-rdfcore-wg@w3.org>
Oops, Graham, I read your posting after writing http://lists.w3.org/Archives/Public/w3c-rdfcore-wg/2001Dec/0004.html. There, Idiom B corresponds pretty much to what you suggested. And I agree that this alternative idiom could be used as a convenient migration path. Sergey Graham Klyne wrote: > > This isn't really a new proposal, so much as some extra definitions that I > see as allowing proposal S to work with some naive usage of RDF. It is my > attempt to pull together comments from other messages into a single place > for consideration. > > My understanding is that at the heart of proposal S is the idea that RDF > literals denote strings. What I want to propose here is an account of how > XML schema datatypes can be used with RDF, scheme S handling of literals, > and the original model theory from F2F. > > (I'm basing much of my understanding of S on Sergey's message at > http://lists.w3.org/Archives/Public/w3c-rdfcore-wg/2001Nov/0312.html and > sliding around the datatype-as-property aspect.) > > Let 'foo' be an XML schema datatype (e.g. 'integer'). The URI derived from > the XML schema specification for this would be: > http://www.w3.org/2001/XMLSchema#foo > or > http://www.w3.org/2001/XMLSchema-datatypes#foo > > XML schema talks about a datatype having a value space and a lexical space > (http://www.w3.org/TR/xmlschema-2/#datatype). > > My proposal is that additional datatype-related URIs be defined, based on > the XML schema space, such as: > http://www.w3.org/2001/XMLSchema-datatypes#foo > http://www.w3.org/2001/XMLSchema-values#foo > http://www.w3.org/2001/XMLSchema-mappings#foo > where: > http://www.w3.org/2001/XMLSchema-datatypes#foo denotes the lexical space of > the datatype. > http://www.w3.org/2001/XMLSchema-values#foo denotes the value space of the > datatype. > http://www.w3.org/2001/XMLSchema-mappings#foo denotes an RDF property that > relates the value space to its lexical space > > Thus, in N3, we might have: > > @prefix xsd-lex: <http://www.w3.org/2001/XMLSchema-datatypes#> . > @prefix xsd-val: <http://www.w3.org/2001/XMLSchema-values#> . > @prefix xsd-map: <http://www.w3.org/2001/XMLSchema-mappings#> . > @prefix ex: <http://example.org/> . > > xsd-lex:integer a rdfs:Class . > xsd-val:integer a rdfs:Class . > xsd-map:integer a rdf:property . > xsd-map:integer rdfs:domain xsd-val:integer . > xsd-map:integer rdfs:range xsd-lex:integer . > > _:number0 rdf:type xsd-val:integer . > _:number0 rdf:xsd-map "0" . > _:number1 rdf:type xsd-val:integer . > _:number1 rdf:xsd-map "1" . > : > (etc.) > > ex:person ex:age_in_years_as_string "10" . > ex:age rdfs:range xsd-lex:integer . > > ex:person ex:age_in_years > [ a xsd-val:integer ; xsd-map:integer "10" ] . > > .. > > What all this means is that there's nothing new to define for RDF. The > idiom for dealing in detail with values and their lexical representation is > pretty much as indicated by S. But the naive approach of using strings > directly is also supported, with a clear migration path (i.e. use new > properties) from the naive approach to the more precise form that is the > preferred idiom. > > #g > > ------------------------- > __ > /\ \ Graham Klyne > / \ \ (GK@ACM.ORG) > / /\ \ \ > / / /\ \ \ > / / /__\_\ \ > / / /________\ > \/___________/
Received on Tuesday, 4 December 2001 17:00:30 UTC