librasqal

Section: C Library Functions (3)
Updated: 2011-01-12
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NAME

librasqal - Rasqal RDF query library

SYNOPSIS

#include <rasqal.h>


 


rasqal_world*world=rasqal_new_world();


rasqal_query_results *results;


raptor_uri *base_uri=raptor_new_uri("http://example.org/foo");


rasqal_query *rq=rasqal_new_query(world,"rdql",NULL);


const char *query_string="select * from <http://example.org/data.rdf>";


 


rasqal_query_prepare(rq,query_string,base_uri);


results=rasqal_query_execute(rq);


while(!rasqal_query_results_finished(results)) {


 for(i=0;i<rasqal_query_results_get_bindings_count(results);i++) {


  const char *name=rasqal_query_results_get_binding_name(results,i);


  rasqal_literal *value=rasqal_query_results_get_binding_value(results,i);


  /* ... */


 }


 rasqal_query_results_next(results);


}


rasqal_free_query_results(results);


rasqal_free_query(rq);


raptor_free_uri(base_uri);


rasqal_free_world(world);



cc prog.c -o prog `pkg-config rasqal --cflags` `pkg-config rasqal --libs`

DESCRIPTION

The Rasqal library provides a high-level interface to RDF query parsing, query construction, query execution over an RDF graph and query results manipulation and formatting. The library provides APIs to each of the steps in the process and provides support for handling multiple query language syntaxes. At present Rasqal supports most of the W3C SPARQL 1.0 Query language, some of SPARQL 1.1 draft and fully supports RDQL.

Rasqal uses the libraptor(3) library for providing URI handling, WWW content retrieval and other support functions.

API REFERENCE

See the HTML API docs that may be installed system wide at /usr/share/gtk-doc/html/rasqal/ or on the web at http://librdf.org/rasqal/docs/api/

API CHANGES

See the Raptor API docs changes section at http://librdf.org/rasqal/docs/api/rasqal-changes.html

CONFORMING TO

SPARQL Query Language for RDF, Eric Prud'hommeaux and Andy Seaborne (eds), W3C Recommendation, 15 January 2008 http://www.w3.org/TR/2008/REC-rdf-sparql-query-20080115/

SPARQL Query Results XML Format, Jeen Broekstra and Dave Beckett (eds), W3C Recommendation, 15 January 2008. http://www.w3.org/TR/2008/REC-rdf-sparql-XMLres-20080115/

RDQL - A Query Language for RDF, Andy Seaborne, W3C Member Submission 9 January 2004 http://www.w3.org/Submission/2004/SUBM-RDQL-20040109/

AUTHOR

Dave Beckett - http://purl.org/net/dajobe/