- From: Simon Raboczi <raboczi@tucanatech.com>
- Date: Wed, 15 Dec 2004 00:23:10 +1000
- To: Dave Beckett <dave.beckett@bristol.ac.uk>
- Cc: public-rdf-dawg@w3.org
On 14/12/2004, at 0:34, Dave Beckett wrote: > > I've updated > SPARQL Variable Binding Results XML Format > http://www.w3.org/2001/sw/DataAccess/rf1/ > > to include some words as well as example, rdf query, xslt, XML Query > and outputs. There are a few issues: > > ISSUE: This is a problem, you cannot distinguish a bound variable > value with an empty string literal, from a variable with no > binding. > > Either go with <var empty="something"/"> or omit the <var/>? > ISSUE: XML style - rename variables to header or head? > > But I can't think of anything else that'd go in the header at present. > > ISSUE: Normativeness of the XML schemas. Pick one? I don't think the <variables> element defined in section 2.2 of the current document shouldn't use empty XML elements to represent the variables. The reason this isn't a good idea is that the variable elements no longer have a consistent type throughout the document. For example, I can't assume that <x/> is always the variable ?x and that I should always expect it to have attributes or element content that represent the RDF node that ?x is bound to. I have to check the parent element, either <variables/> or <result/> to figure out in which context I should be interpreting <x/>. I'm not familiar with RELAXNG, but I'm of the impression that XML Schema supports space-delimited lists of qnames or tokens as a simple type. I'd suggest that something like <results variables="x y z"> <result> <x>foo</x> <y>bar</y> </result> <result> <x>baz</x> <z>quux</z> </result> </results> would give every element a consistent type. Do we need the outermost <dawg-result> element?
Received on Tuesday, 14 December 2004 14:23:51 UTC