- From: Graham Klyne <GK-lists@ninebynine.org>
- Date: Mon, 11 Oct 2010 16:28:16 +0100
- To: Tim Berners-Lee <timbl@w3.org>
- CC: Jonathan Rees <jar@creativecommons.org>, "www-tag@w3.org" <www-tag@w3.org>
Tim Berners-Lee wrote: > If rdf:ID is defined as having uniqueness constraints then it is surely broken for > RDF as the same thing can of course be referred to in lots of of places > in the file, with exactly the same syntax. Well, yes. I tend to ignore it in favour of rdf:about, for that reason. I think the constraints are a diluted carry over from the earlier RDF spec. According to the W3C validator (http://www.w3.org/RDF/Validator/), the following is broken in exactly the way you suggest: [[ <?xml version="1.0"?> <rdf:RDF xmlns:rdf="http://www.w3.org/1999/02/22-rdf-syntax-ns#" xmlns:dc="http://purl.org/dc/elements/1.1/"> <rdf:Description rdf:ID="a"> <dc:title>A label for 'a'</dc:title> </rdf:Description> <rdf:Description rdf:ID="a"> <dc:creator>A creator for 'a'</dc:creator> </rdf:Description> </rdf:RDF> ]] [[ Error: {W105} Redefinition of ID: a[Line = 7, Column = 31] Error: {W105} Previous definition of 'a'.[Line = 4, Column = 31] ]] #g -- Tim Berners-Lee wrote: > If rdf:ID is defined as having uniqueness constraints then it is surely broken for > RDF as the same thing can of course be referred to in lots of of places > in the file, with exactly the same syntax. > > Tim > >> >> >> Jonathan Rees wrote: >>> [...] The RDF/XML DTD >>> (http://www.w3.org/XML/9710rdf-dtd/rdf.dtd) gives the rdf:ID attribute >>> type ID, and the XML specs (including xml:id and Xpointer) do their >>> very best to ensure that attributes with type ID are as much as >>> possible the same as xml:id. The RDF/XML spec also makes rdf:ID very >>> similar to xml:id - same syntactic and uniqueness constraints. So it >>> seemed highly likely to me that rdf:ID defines fragids the same way >>> that xml:id does. > >
Received on Monday, 11 October 2010 15:30:06 UTC