- From: Phil Dawes <pdawes@users.sf.net>
- Date: Mon, 3 May 2004 14:58:19 +0100
- To: Patrick Stickler <patrick.stickler@nokia.com>
- Cc: "ext Chris Bizer" <chris@bizer.de>, <www-rdf-interest@w3.org>
Hi Patrick, Patrick Stickler writes: > > RDFQ has been a useful "thought experiment" that I would like to have > seen reach a higher stage of maturity in the implementation, but further > development is at the moment, and probably for the summer, "on ice". > That's a shame - for me it represents the most promising query language for cross-store querying. I suspect querying across multiple sources will start to become an important requirement for applications in the near future, especially if tools like Chris's D2R mapping software open up existing relational databases to RDF query languages. RDFQ is compelling for this sort of thing because of the following features: 1) supports adding RDF knowledge to be considered in addition to the contents of the knowledge base being queried. - important when carrying out a query across multiple sources since passing existing results between stores facilitates additional results to be found. 2) supports multiple queries in one dispatch - useful when trying to augument existing knowledge with extra descriptive triples - e.g. labels, comments, types. Also I often find myself needing to do a number of un-related queries to obtain enough information to carry out an action. 3) supports named graphs - important when results are syndicated from multiple sources. The only thing that puzzled me about the RDFQ spec[1] is the result format. It's currently constrained to being either a set of consise-bounded-descriptions or in the rdf format from the recording-query-results[2] document. For me, the most useful result format for server-side querying is a single rdf graph containing all the matched triples. This is because usually (in software I've written) query results are required to be used in tandem with other knowledge to carry out the required functionality. Getting the results as a graph enables the client to merge the information with its existing internal store. Cheers, Phil http://phildawes.net/ [1] http://sw.nokia.com/rdfq/RDFQ.html [2] http://www.w3.org/2003/03/rdfqr-tests/recording-query-results.html
Received on Monday, 3 May 2004 11:02:40 UTC