- From: Bijan Parsia <bparsia@cs.man.ac.uk>
- Date: Sat, 5 Aug 2006 22:40:28 +0100
- To: RDF Data Access Working Group <public-rdf-dawg@w3.org>
It occurs to me that one way to manage the distinguished/ semidistinguished/nondistinguished mechanism a bit more neatly would be to dispense with the distinction between BNodes and query variables (except for spelling and syntactic restrictions on placements) in queries, and force the range of the variables to depend on the query form. That is, SELECT forces distinguished variables, and ASK the rest. We could then allow variables to be listed in the "head" of the ASK clause (as in the SELECT clause), so that the distinction between semi and nondistinguished variables is merely projection/listing in the head. You could list BNodes in the head just like other query variables, or dispense with them altogether, or allow them to have their present form, to wit, being dedicately non-distinguished. Unfortunately, while rather neat, it's not very practical, as people are used to using SELECT as their query form (a la SQL) and, especially in the RDF case, likely to want semi-distinguished variables by default. But it *would* be neat ;) Perhaps an argument could be made that violating the SQL expections would help people avoid false analogies. This is a common problem with things that look similar but behave rather differently, people think that they should behave as similarly as they look. Cheers, Bijan.
Received on Saturday, 5 August 2006 21:39:47 UTC