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QName to URI reference

From: Jonathan Borden <jborden@mediaone.net>
Date: Thu, 8 Mar 2001 22:18:18 -0500
To: <www-rdf-comments@w3.org>
Message-ID: <00d901c0a847$9697f7a0$0201a8c0@ne.mediaone.net>
Mapping namespace qualified element names to URIs

REC: insert '#' between namespace URI and local name when namespace URI ends
in alphanumeric.


The current convention of concatenating a namespace URI reference and local
name to convert a QName to URI reference is inconsistent with common usage
of QNames

For example in XML Schema the QName: "xsd:unsignedInt" is used to refer to
the simple datatype "unsigned integer". This corresponds to the fragment:

<simpleType name="unsignedInt" id="unsignedInt" ...>

within the document resolved from the URI:
http://www.w3.org/2000/10/XMLSchema which is bound to the "xsd" prefix.

This simpleType definition is referenced by the URI reference:

http://www.w3.org/2000/10/XMLSchema#unsignedInt

however the RDF convention would produce
http://www.w3.org/2000/10/XMLSchemaunsignedInt

It is not acceptable for RDF and XML Schema (among others) to have different
conventions for naming the same concepts/resources.

A proposal:

It is necessary to map namespace qualified element names (QNames) to URIs
for a variety of purposes but particularly in RDF. The RDF Model and Syntax
specification directs this mapping to occur via concatenation of the
namespace URI with the local name. This is acceptable when the namespace URI
does not end with a character which cannot be used to begin an element name
(an NCName) i.e. a Letter or '_', because the first non Letter or '_'
encountered from the end of the URI can be used to delimit the namespace URI
from the element name. Yet when the URI ends in a Letter or '_', several
URI, NCName pairs may map to the same concatenated URI.

It is proposed for namespace URIs that when a namespace URI ends in a Letter
or '_' that a '#' be inserted between the namespace URI and the element tag
name to create the resultant URI. When such a URI is resolvable to a
resource of media type text/html or text/xml, the fragment identifier
resolves to an identifier of the element name. When the document is of type
text/html, the identifier might point to a section which describes the
element. When the document is of type text/xml (or application/xml) and the
base document contains an RDF Schema, the identifier is expected to point to
the Property or Class definition for the element name.

Jonathan Borden
The Open Healthcare Group
http://www.openhealth.org
Received on Thursday, 8 March 2001 22:16:42 GMT

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