On 01/02/07, Thomas Winningham <[EMAIL PROTECTED]> wrote: > Check out SPARQL,
Absolutely. Couple of other points: You do have the option of getting the results (view) in RDF/XML using CONSTRUCT, or SPARQL results XML format, but also several of the SPARQL engines support a JSON equivalent of the results format - handy for in-browser processing. The current SPARQL spec doesn't include aggregate functions, things like COUNT and GROUP BY, but I think some of the implementations support these as extensions (along with custom extensions which could do calculations or whatever). It's also possible to do aggregates on the results (grouping with XSLT 1.0 can get hairy, but XSLT 2.0 has built-in support and it should be trivial with JSON). Something I think is a useful pattern is a two-phase query, first do a CONSTRUCT (producing an intermediate RDF model) and then do a SELECT on those results. The advantage here is that CONSTRUCT allows you to map across vocabularies, so although the CONSTRUCT will be tied to the domain vocabulary of the soure data, the SELECT can be domain-independent. Not long ago in some contract work I used this with a made-up report vocabulary in the middle, and it meant that the logical query was separated from the presentation part of the code (I had preset queries for SELECT feeding preset XSLT to produce HTML). I didn't have chance to look into it, but the Fresnel vocabulary might make a good candidate for using in the intermediate model. re. fun with CONSTRUCT, see also: http://www.thefigtrees.net/lee/blog/2007/01/using_rdf_on_the_web_a_vision.html http://dannyayers.com/2006/12/24/merging-results-from Cheers, Danny. /me giggles at male_members -- http://dannyayers.com _______________________________________________ General mailing list [email protected] http://simile.mit.edu/mailman/listinfo/general
