- From: Arjohn Kampman <arjohn.kampman@aduna-software.com>
- Date: Fri, 06 Mar 2009 11:32:49 +0100
- To: Leigh Dodds <leigh.dodds@talis.com>
- CC: public-rdf-dawg-comments@w3.org
Hi all, Sesame also supports this in its HTTP protocol and we use it a lot. We decided to use a '$' prefix for variable names though, to prevent accidental name collisions with other URL-parameters (e.g. "query"). Regards, Arjohn Leigh Dodds wrote: > Hi, > > I have the following featur esuggestion for the WG. > > Feature: Parameterised Queries > > Feature Description: > > Extend the SPARQL protocol such that additional URL parameters in > the query string (or a subset that match > a specific naming convention) are reflected into the query as > initial variable bindings. > > Example: > > E.g. for a query such as: > > PREFIX foaf: <http://xmlns.com/foaf/0.1/> > SELECT ?name > WHERE { > ?x foaf:name ?name. > ?x foaf:weblog ?blog. > } > > A protocol request of the form: > > /sparql?query=...&blog=http://www.example.org/blog > > Would bind ?blog to the value in the URL parameter before it is > matched against the dataset. > > Existing Implementations > > ARQ supports this usage in its core URL, and I have used this to > implement the above style of parameter passing in > several apps and endpoints whilst at my previous employer. > > Use Cases > > Enable support SQL style parameterised query directly from the SPARQL > protocol. In conjunction with the proposed Query By Reference > feature it enables the creation of simple "web APIs" using only the > SPARQL protocol. E.g. I am able to publish a common > SPARQL query that does some useful data extraction, and then reuse > that query by altering the passed parameters. > > Even without the Query By Reference feature it would simplify > interaction with an endpoint (change url parameter(s) not query) and > would allow the endpoint to cache and parse a query for repeated use, > thereby removing any query parsing overheads. > > Cheers, > > L. > -- Arjohn Kampman, Senior Software Engineer Aduna - Semantic Power www.aduna-software.com
Received on Friday, 6 March 2009 10:33:27 UTC