- From: Aaron Swartz <aswartz@swartzfam.com>
- Date: Sat, 10 Feb 2001 22:11:23 -0800
- To: Dan Brickley <danbri@w3.org>, Dave Beckett <dave.beckett@bristol.ac.uk>
- CC: David Megginson <david@megginson.com>, <www-rdf-interest@w3.org>
Dan Brickley <danbri@w3.org> wrote: >>>> I feel it might be needed for serialisation of the RDF graph to >>>> RDF/XML, but I haven't implemented that yet. >>> Unfortunately, the serialization of an RDF graph is impossible in the >>> general case: the XML Namespaces spec describes two-part names, but >>> RDF treats them as single part names, and the act of combining the two >>> is lossy. ... >> I appreciated this, which is why in Redland I'll probably start >> recording namespace URIs/prefixes in the RDF model just for >> re-serialisation purposes something like >> >> [model URI] -> [redland:hasXMLnsPrefix] -> "xmlns:foo=http://foo.com/ns"] > Maybe we could agree to use eg dc:title or rdfs:label for this, to express > preferred namespace prefixes of a vocabualry? For SWAG[1] I've proposed a similar term as part of MetaVocab[2]. I don't think reusing another property would be a good idea since things could quickly get confused. In my own databases I've set up an internally-maintained constraint of a unique 1:1 correspondence of URIs to prefixes. However, it is important to remember that since RDF simply concatenates the URIs, it is not necessary to store this information to re-serialize. For example: xmlns:foo="http://foo.com/ns" foo:bar -> http://foo.com/nsbar To re-serialize, you simply break the URI at the first character not allowed in a Qname (here a /). xmlns:a="http://foo.com/" http://foo.com/nsbar <- a:nsbar Sure, the re-serialized graph will not contain the same namespace URIs as the original, but to an RDF parser this will make no difference. (This will eventually cause a problem for XML signatures, since the Canonical XML will be different. Perhaps we need a Canonical RDF? Would it just be a list of triples?) [1] http://purl.org/swag/ [2] http://webns.net/mvcb/ -- [ Aaron Swartz | me@aaronsw.com | http://www.aaronsw.com ]
Received on Saturday, 10 February 2001 23:12:13 UTC