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Sail Ouplementation

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okram edited this page Jan 14, 2011 · 36 revisions

Sail is an RDF triple/quad store interface developed by OpenRDF. Any database the implements the Sail interfaces properly is a valid RDF triple/quad store. A graph database is a great way to build a triple/quad store because its possible to mix indexing and graph traversals to solve the RDF “pattern match” problem. To go from Graph to Sail, simply use GraphSail. GraphSail requires an IndexableGraph (e.g. TinkerGraph, Neo4jGraph, OrientGraph). The examples below use TinkerGraph and expose it as a GraphSail and thus, a Sail.

Basic Statement Handling

A statement in RDF is a triple or quad. The components of a statement are called: subject, predicate, object, and graph/context. The subject can be a URI or blank node. The predicate can only be a URI. The object can be a URI, blank node, or literal. Finally, the graph (or context) can be a URI or blank node.

Sail sail = new GraphSail(new TinkerGraph());
SailConnection sc = sail.getConnection();
ValueFactory vf = sail.getValueFactory();
sc.addStatement(vf.createURI("http://tinkerpop.com#1"), vf.createURI("http://tinkerpop.com#knows"), vf.createURI("http://tinkerpop.com#3"), vf.createURI("http://tinkerpop.com"));
sc.addStatement(vf.createURI("http://tinkerpop.com#1"), vf.createURI("http://tinkerpop.com#name"), vf.createLiteral("marko"), vf.createURI("http://tinkerpop.com"));
sc.addStatement(vf.createURI("http://tinkerpop.com#3"), vf.createURI("http://tinkerpop.com#name"), vf.createLiteral("josh"), vf.createURI("http://tinkerpop.com"));

System.out.println("get statements: ?s ?p ?o ?g");
CloseableIteration<? extends Statement, SailException> results = sc.getStatements(null, null, null, false);
while(results.hasNext()) {
    System.out.println(results.next());
}

System.out.println("\nget statements: http://tinkerpop.com#3 ?p ?o ?g");
results = sc.getStatements(vf.createURI("http://tinkerpop.com#3"), null, null, false);
while(results.hasNext()) {
    System.out.println(results.next());
}
get statements: ?s ?p ?o ?g
(http://tinkerpop.com#1, http://tinkerpop.com#knows, http://tinkerpop.com#3) [http://tinkerpop.com]
(http://tinkerpop.com#3, http://tinkerpop.com#name, "josh") [http://tinkerpop.com]
(http://tinkerpop.com#1, http://tinkerpop.com#name, "marko") [http://tinkerpop.com]

get statements: http://tinkerpop.com#3 ?p ?o ?g
(http://tinkerpop.com#3, http://tinkerpop.com#name, "josh") [http://tinkerpop.com]
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