- From: Dan Brickley <danbri@danbri.org>
- Date: Tue, 4 Sep 2012 20:40:37 +0800
- To: Richard Smith <richard@ex-parrot.com>
- Cc: Richard Cyganiak <richard@cyganiak.de>, public-rdf-comments@w3.org
On 4 September 2012 20:26, Richard Smith <richard@ex-parrot.com> wrote: > > Hi Richard, > > Richard Cyganiak wrote: >> >> Richard Smith wrote: > > > [snip] > > >>> <xsd:schema xmlns:xsd="http://www.w3.org/2001/XMLSchema" >>> xmlns:rdf="http://www.w3.org/1999/02/22-rdf-syntax-ns#" >>> xmlns:dct="http://purl.org/dc/terms/"> >>> <xsd:annotation><xsd:appinfo> >>> <rdf:RDF><rdf:Resource about=""> >>> <dct:issued >>> rdf:datatype="xsd:gYearMonth">2012-08</dct:issued> >>> </rdf:Resource></rdf:RDF> >>> </xsd:appinfo></xsd:annotation> >>> </xsd:schema> >>> >>> I certainly don't think a substantive change is required. But at the risk >>> of advancing the argument that I wrote bad RDF and therefore it's a bug in >>> someone else's standard, I do think a non-normative note mentioning this >>> difference might be in order. >> >> >> The xs: prefix is conventionally associated with one namespace URI, and >> the xsd: prefix is conventionally associated with another URI. > > > Except that isn't applied uniformly, even amongst the W3 recommendations. > For instance, in section 2.1 of the XML Schema Primer > > http://www.w3.org/TR/xmlschema-0/#POSchema > > the example begins with > > > <xsd:schema xmlns:xsd="http://www.w3.org/2001/XMLSchema"> > > and that recommendation uniformly uses 'xsd' as the prefix for the XML > Schema namespace, without the '#'. > > And a google search finds comparably many hits for "xsd:element" and > "xs:element", so even if using 'xs' is recommended practice, it certainly > doesn't seem to be established practice. > > > >> As far as I know, we have no evidence, and no reason to believe, that this >> is a common confusion. > > > Probably not in the form I gave. But the much the same problem manifests in > a second manner that I hadn't considered when I sent the earlier email. I > think this is more serious. > > The implication of section 5 of the RDF 1.1 Concepts draft is that it should > be possible to use suitable types from third-party XML Schemas. A real > example: English counties have a three-letter abbreviation known as a > Chapman code, and I can define an XML Schema type to represent them. E.g. > > <xs:schema xmlns="http://www.w3.org/2001/XMLSchema" > targetNamespace="http://www.example.com/geo"> > <xs:simpleType name="chapman-code"> > <xs:restriction base="xs:string"> > <!-- I could enumerate them or use a pattern --> > </xs:restriction> > <xs:simpleType> > </xs:schema> > > If I want to use this type in RDF, what is its datatype URI? The RDF 1.1 > Concepts draft is silent on the issue. By comparison with XML Schema, we > might infer that it should be > > http://www.example.com/geo#chapman-code > > But nothing in the Concepts draft says we should add a '#' in this way. And > I am aware of nothing in the XML Schema recommendations that defines the > notion of a datatype URI for a schema type. Just FWIW, this old-ish Note discusses that issue: http://www.w3.org/TR/swbp-xsch-datatypes/ Dan
Received on Tuesday, 4 September 2012 12:41:05 UTC