test-sparql1.c

/*
 * test-sparql1.c - run SPARQL query against a librdf.sqlite model
 *
 * created for librdf.sqlite issue #17, https://github.com/mro/librdf.sqlite/issues/17
 *
 * compile:
 * gcc -I/usr/include/raptor2 -I/usr/include/rasqal -lrdf -lsqlite3 -o "test-sparql1" "test-sparql1.c"
 */
#include <stdio.h>
#include "rdf_storage_sqlite_mro.c"

static const char file_path[] = "books_sample.sqlite";

static const char query_string[] = ""
    "SELECT ?author ?title\n"
    "WHERE {\n"
    "       ?book a <http://dbpedia.org/ontology/Book> .\n"
    "       ?book <http://xmlns.com/foaf/0.1/name> ?title .\n"
    "       ?book <http://dbpedia.org/ontology/author> ?author.\n"
    "}\n";

int main()
{
    // for brevity error handling is removed
    librdf_world *world = librdf_new_world();

    // register SQLite storage factory
    librdf_init_storage_sqlite_mro(world);


    const char *options = "new='no',contexts='yes',synchronous='off'";


    librdf_storage *store = librdf_new_storage(world,
                                               LIBRDF_STORAGE_SQLITE_MRO,
                                               file_path,
                                               options);

    librdf_model *model = librdf_new_model(world, store, NULL);


    librdf_query *rdf_query = librdf_new_query(world, "sparql", NULL,
                                               (const unsigned char*) query_string,
                                               NULL);

    librdf_query_results *res = librdf_query_execute(rdf_query, model);
    if (res) {
        // display query results to console in CSV format
        librdf_query_results_to_file_handle2(res, stdout, "csv",
                                             NULL, NULL, NULL);
    }

    librdf_free_query_results(res);
    librdf_free_query(rdf_query);
    librdf_free_model(model);
    librdf_free_storage(store);
    librdf_free_world(world);
}