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Chapter 8. Quick Start for the RDF Graph Feature
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## Chapter 8. Quick Start for the RDF Graph Feature

This section provides examples for the major capabilities of the RDF Graph feature. Each example is self-contained: it typically creates a graph, adds triples, performs a query that may involve inference, displays the result, and drops the model.

These examples can be found in the `examples/` directory.

This section includes examples that do the following:

- Create a graph (or named graph) and insert/delete triples.

- Create an inferred graph (or inferred named graph) and insert/delete inferred triples belonging to a graph.

- Load a RDF file into the Oracle NoSQL Database.

- Run several SPARQL queries using a "family" ontology, including:

- SPARQL query features such as LIMIT, OFFSET, ASK, DESCRIBE, CONSTRUCT.

- RDF Graph feature query options like TIMEOUT, DOP, ORDERED, INF_ONLY, ASSERTED_ONLY.

- RDF Graph feature hints such as PLAN.

- Use the Apache Jena ARQ built-in function.

- Use a SELECT cast query.

- SPARQL Update requests to insert data into the Oracle NoSQL Database.

- Create a connection to an Oracle NoSQL Database using `OracleNoSqlConnection`.

- Use Oracle NoSQL Database connection pooling.

- Generate sampling data for a specified graph or data set.

To run a query, you must do the following:

1. Include the code in a Java source file. The examples used in this section are provided as files in the examples directory of the package.

2. Compile the Java source file. For example:

       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 Example.java

3. Run the compiled file. For example:

       java -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 Example <store_name \
       > <host_name> <host_port>

## Example1.java: Create a default graph and add/delete triples

This example shows how to add/remove a set of triples over a default graph stored in an Oracle NoSQL Database.

    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 Example1 {

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

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

    OracleNoSqlConnection conn
         = OracleNoSqlConnection.createInstance(szStoreName,
                                                szHostName,
                                                szHostPort);

    // This object will handle operations over the default graph
    OracleGraphNoSql graph = new OracleGraphNoSql(conn);
    graph.clearRepository(); //Clear the graph including inferred triples

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

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

    String queryString = " select ?x ?y WHERE {?x <u:parentOf> ?y}";
    System.out.println("Execute query " + queryString);

    Model model = new OracleModelNoSql(graph);
    Query query = QueryFactory.create(queryString);
    QueryExecution qexec = QueryExecutionFactory.create(query, model);

    try {
          ResultSet results = qexec.execSelect();
          ResultSetFormatter.out(System.out, results, query);
        }

    finally {
          qexec.close();
        }

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

    queryString = "select ?x ?y ?z WHERE {?x ?y ?z}";
    System.out.println("Execute query " + queryString);

    query = QueryFactory.create(queryString) ;
    qexec = QueryExecutionFactory.create(query, model);

    try {
          ResultSet results = qexec.execSelect();
          ResultSetFormatter.out(System.out, results, query);
        }

    finally {
          qexec.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 Example.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 \
    Example1 <store_name> <host_name> <host_port>

    Execute query select ?x ?y WHERE {?x <u:parentOf> ?y}
    -----------------------
    | x        | y        |
    =======================
    | <u:Mary> | <u:Jack> |
    | <u:John> | <u:Mary> |
    -----------------------

    Execute query select ?x ?y ?z WHERE {?x ?y ?z}
    --------------------------------------
    | x        | y            | z        |
    ======================================
    | <u:Mary> | <u:parentOf> | <u:Jack> |
    --------------------------------------

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