RE: Querying dbpedia from the command line?



> -----Original Message-----
> From: public-lod-request@w3.org [mailto:public-lod-request@w3.org] On
> Behalf Of Richard Cyganiak
> Sent: 18 September 2008 12:29
> To: Bob DuCharme
> Cc: public-lod@w3.org
> Subject: Re: Querying dbpedia from the command line?

> 1. SPARQL is great, but too verbose for the command line. I would
> really like to use a single-line, XPath-style query language for RDF
> in situations like this. There are a couple of proposals for such a
> language out there, several of them are called "RDFPath" and there's
> Uche Ogbuji's Versa. It would be really great to see some progress in
> this area. The first one of these languages to get a well-packaged
> implementation on top of the Jena API will probably win.

Not only the command line but also for using in applications.  A more compact language would allow use in APIs.  I know some people have done their own libraries to do this but it would be nice to have a common compact language that translated to SPARQL (and so can be sent over the wire to existing endpoints).  One of the things that makes SPARQL verbose is full URIs and the prefix declarations.  Either the local context has to have local prefix declarations for compact URIs via prefixed names or servers need to publish their provided prefixes which they add to any query.

Path-like constructs can be added to SPARQLe.g.
http://jena.sourceforge.net/ARQ/property_paths.html

or PSPARQL or SPARQLeR.

> 3. We are all waiting for SPARQL processors that federate multiple
> SPARQL endpoints transparently into a single endpoint. Progress is
> being made in this area, but it's slow. Meanwhile, there is a very
> nice 80/20 solution to this problem: Andy Seaborne has implemented a
> SERVICE keyword for his extended variant of SPARQL, which allows you
> to address parts of a SPARQL query to a specific endpoint. This seems
> like an easy win for data integration demos.

One of the issues here might be the maturity of the ecosystem (in the general sense, not just money but also other motivations for running a service).  The present stage is open data is appearing but may be not yet reached critical mass to cause combination services to appear yet.  As open data continues to appear, applications driven by it will mature and new ones appear and that can drive the appearance of federated services.  Keep adding open data!

        Andy

>
> Richard
>
>
> >
> >
> > Bob

Received on Friday, 19 September 2008 11:08:37 UTC