Library Version 12.1.3.0

Example8.java: SPARQL Construct query
Prev | Chapter 8. Quick Start for the RDF Graph Feature | Next

## Example8.java: SPARQL Construct query

This example shows a SPARQL CONSTRUCT query. It inserts triples that assert the following:

- John is a parent of Mary.

- John is a parent of Jack.

- Amy is a parent of Jack.

- Each parent loves all of his or her children.

It then constructs an RDF graph with information about who loves whom.

    import com.hp.hpl.jena.graph.*;
    import com.hp.hpl.jena.query.*;
    import com.hp.hpl.jena.rdf.model.Model;
    import oracle.rdf.kv.client.jena.*;

    public class Example8
    {
      public static void main(String[] args) throws Exception
      {

    String szStoreName  = args[0];
    String szHostName   = args[1];
    String szHostPort   = args[2];
    String szModelName  = args[3];

    System.out.println("Create Oracle NoSQL connection");
    OracleNoSqlConnection conn
    = OracleNoSqlConnection.createInstance(szStoreName,
                                           szHostName,
                                           szHostPort);

    System.out.println("Create Oracle NoSQL model");

    OracleModelNoSql model =
                     OracleModelNoSql.createOracleModelNoSql(szModelName,
                                                             conn);

    System.out.println("Clear model");
    model.removeAll();

    System.out.println("Get graph from model");
    OracleGraphNoSql graph = model.getGraph();

    System.out.println("Add triples");

    graph.add(Triple.create(Node.createURI("u:John"),
                            Node.createURI("u:parentOf"),
                            Node.createURI("u:Mary")));

    graph.add(Triple.create(Node.createURI("u:John"),
                            Node.createURI("u:parentOf"),
                            Node.createURI("u:Jack")));

    graph.add(Triple.create(Node.createURI("u:Amy"),
                            Node.createURI("u:parentOf"),
                            Node.createURI("u:Jack")));

    String szQuery = "CONSTRUCT { ?s <u:loves> ?o } " +
                     "WHERE {?s <u:parentOf> ?o }";

    System.out.println("Execute construct query " + szQuery);

    Query query = QueryFactory.create(szQuery) ;
    QueryExecution qexec = QueryExecutionFactory.create(query, model);

    Model constructModel = qexec.execConstruct();
    System.out.println("Construct result = " + constructModel.toString());

    qexec.close();
    constructModel.close();

    model.close();
    conn.dispose();
      }
    }

The following are the commands to compile and run this example, as well as the expected output of the java command.

    javac -classpath ./:./jena-core-2.7.4.jar:./jena-arq-2.9.4.jar: \
    ./sdordfnosqlclient.jar:./kvclient.jar:./xercesImpl-2.10.0.jar: \
    ./slf4j-api-1.6.4.jar:./slf4j-log4j12-1.6.4.jar:./log4j/1.2.16.jar: \
    ./jena-iri-0.9.4.jar:./xml-apis-1.4.01.jar Example8.java

    javac -classpath ./:./jena-core-2.7.4.jar:./jena-arq-2.9.4.jar: \
    ./sdordfnosqlclient.jar:./kvclient.jar:./xercesImpl-2.10.0.jar: \
    ./slf4j-api-1.6.4.jar:./slf4j-log4j12-1.6.4.jar:./log4j/1.2.16.jar: \
    ./jena-iri-0.9.4.jar:./xml-apis-1.4.01.jar Example8 <store_name> \
    <host_name> <host_port> <graph_name>
    Execute construct query CONSTRUCT { ?s <u:loves> ?o }
    WHERE {?s <u:parentOf> ?o }
    Construct result = <ModelCom   {u:Amy @u:loves u:Jack;
    u:John @u:loves u:Mary; u:John @u:loves u:Jack} | >

Prev | Up | Next
Example7.java: SPARQL Describe query | Home | Example9.java: SPARQL OPTIONAL query