Table of Contents
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:
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.
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
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>
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> |
--------------------------------------