Beispiel #1
0
        public void SparqlBgpEvaluation()
        {
            //Prepare the Store
            TripleStore store = new TripleStore();
            Graph       g     = new Graph();

            FileLoader.Load(g, "resources\\Turtle.ttl");
            store.Add(g);

            SparqlQueryParser parser     = new SparqlQueryParser();
            SparqlQuery       q          = parser.ParseFromString(@"PREFIX rdfs: <http://www.w3.org/2000/01/rdf-schema#>
SELECT * WHERE {?s ?p ?o . ?s rdfs:label ?label}");
            Object            testResult = store.ExecuteQuery(q);

            ISparqlAlgebra testAlgebra = q.ToAlgebra();

            if (testResult is SparqlResultSet)
            {
                SparqlResultSet rset = (SparqlResultSet)testResult;
                Console.WriteLine(rset.Count + " Results");
                foreach (SparqlResult r in rset)
                {
                    Console.WriteLine(r.ToString());
                }
                Console.WriteLine();
            }

            //Create some Triple Patterns
            TriplePattern t1 = new TriplePattern(new VariablePattern("?s"), new VariablePattern("?p"), new VariablePattern("?o"));
            TriplePattern t2 = new TriplePattern(new VariablePattern("?s"), new NodeMatchPattern(g.CreateUriNode("rdfs:label")), new VariablePattern("?label"));
            TriplePattern t3 = new TriplePattern(new VariablePattern("?x"), new VariablePattern("?y"), new VariablePattern("?z"));
            TriplePattern t4 = new TriplePattern(new VariablePattern("?s"), new NodeMatchPattern(g.CreateUriNode(":name")), new VariablePattern("?name"));

            //Build some BGPs
            Bgp selectNothing  = new Bgp();
            Bgp selectAll      = new Bgp(t1);
            Bgp selectLabelled = new Bgp(new List <ITriplePattern>()
            {
                t1, t2
            });
            Bgp selectAllDisjoint = new Bgp(new List <ITriplePattern>()
            {
                t1, t3
            });
            Bgp selectLabels = new Bgp(t2);
            Bgp selectNames  = new Bgp(t4);
            //LeftJoin selectOptionalNamed = new LeftJoin(selectAll, new Optional(selectNames));
            LeftJoin selectOptionalNamed = new LeftJoin(selectAll, selectNames);
            Union    selectAllUnion      = new Union(selectAll, selectAll);
            Union    selectAllUnion2     = new Union(selectAllUnion, selectAll);
            Filter   selectAllUriObjects = new Filter(selectAll, new UnaryExpressionFilter(new IsUriFunction(new VariableTerm("o"))));

            //Test out the BGPs
            //Console.WriteLine("{}");
            //this.ShowMultiset(selectNothing.Evaluate(new SparqlEvaluationContext(null, store)));

            //Console.WriteLine("{?s ?p ?o}");
            //this.ShowMultiset(selectAll.Evaluate(new SparqlEvaluationContext(null, store)));

            //Console.WriteLine("{?s ?p ?o . ?s rdfs:label ?label}");
            //SparqlEvaluationContext context = new SparqlEvaluationContext(null, store);
            //this.ShowMultiset(selectLabelled.Evaluate(context));
            //SparqlResultSet lvnResult = new SparqlResultSet(context);

            //Console.WriteLine("{?s ?p ?o . ?x ?y ?z}");
            //this.ShowMultiset(selectAllDisjoint.Evaluate(new SparqlEvaluationContext(null, store)));

            //Console.WriteLine("{?s ?p ?o . OPTIONAL {?s :name ?name}}");
            //this.ShowMultiset(selectOptionalNamed.Evaluate(new SparqlEvaluationContext(null, store)));

            Console.WriteLine("{{?s ?p ?o} UNION {?s ?p ?o}}");
            this.ShowMultiset(selectAllUnion.Evaluate(new SparqlEvaluationContext(null, new InMemoryDataset(store))));

            Console.WriteLine("{{?s ?p ?o} UNION {?s ?p ?o} UNION {?s ?p ?o}}");
            this.ShowMultiset(selectAllUnion2.Evaluate(new SparqlEvaluationContext(null, new InMemoryDataset(store))));

            Console.WriteLine("{?s ?p ?o FILTER (ISURI(?o))}");
            this.ShowMultiset(selectAllUriObjects.Evaluate(new SparqlEvaluationContext(null, new InMemoryDataset(store))));
        }