SPARQL client

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Description

Load SPARQL SELECT query result tables as a data frame, or UPDATE the triple store by connecting to an end-point over HTTP.

The development of this library has been developed in part within the COMBINE project supported by the ONR Global NICOP grant N62909-11-1-7060.

Details

Package: SPARQL
Type: Package
Version: 1.15
Date: 2013-10-23
License: GPL-3
Depends: XML
LazyLoad: yes

Author(s)

Willem Robert van Hage <willem.van.hage@synerscope.com>, with contributions from: Tomi Kauppinen, Benedikt Graeler, Christopher Davis, Jesper Hoeksema, Alan Ruttenberg, and Daniel Bahls. Maintainer: Willem Robert van Hage <willem.van.hage@synerscope.com>

References

SPARQL specification, http://www.w3.org/TR/rdf-sparql-query/.
Examples of SPARQL end-points, http://www.w3.org/wiki/SparqlEndpoints.

Examples

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## Not run: 
d <- SPARQL(url="http://services.data.gov.uk/reference/sparql",
            query="SELECT * WHERE { ?s ?p ?o . } LIMIT 10",
            ns=c('time','<http://www.w3.org/2006/time#>'))

is.data.frame(d$results)

# draw a pie chart from data from the Linked Open Piracy data set
endpoint <- "http://semanticweb.cs.vu.nl/lop/sparql/"
q <-
  "SELECT *
   WHERE {
     ?event sem:hasPlace ?place .
     ?place eez:inPiracyRegion ?region .
   } LIMIT 20"
prefix <- c("lop","http://semanticweb.cs.vu.nl/poseidon/ns/instances/",
            "eez","http://semanticweb.cs.vu.nl/poseidon/ns/eez/")
res <- SPARQL(endpoint,q,prefix)$results
pie(sort(table(res$region)),col=rainbow(12))

## End(Not run)