public static void Main()
{
System.Net.ServicePointManager.Expect100Continue = false; // don't send HTTP Expect: headers which confuse some servers
string endpoint = "http://dbpedia.org/sparql";
string query =
"PREFIX owl: <http://www.w3.org/2002/07/owl#>\n" +
"PREFIX xsd: <http://www.w3.org/2001/XMLSchema#>\n" +
"PREFIX rdfs: <http://www.w3.org/2000/01/rdf-schema#>\n" +
"PREFIX rdf: <http://www.w3.org/1999/02/22-rdf-syntax-ns#>\n" +
"PREFIX foaf: <http://xmlns.com/foaf/0.1/>\n" +
"PREFIX dc: <http://purl.org/dc/elements/1.1/>\n" +
"PREFIX : <http://dbpedia.org/resource/>\n" +
"PREFIX dbpedia2: <http://dbpedia.org/property/>\n" +
"PREFIX dbpedia: <http://dbpedia.org/>\n" +
"PREFIX skos: <http://www.w3.org/2004/02/skos/core#>\n" +
"\n" +
"SELECT ?property ?hasValue ?isValueOf\n" +
"WHERE {\n" +
" { <http://dbpedia.org/resource/Category:First-person_shooters> ?property ?hasValue }\n" +
" UNION\n" +
" { ?isValueOf ?property <http://dbpedia.org/resource/Category:First-person_shooters> }\n" +
"}\n";
SparqlHttpSource source = new SparqlHttpSource(endpoint);
Console.WriteLine("RunSparqlQuery(query, Console.Out):");
source.RunSparqlQuery(query, Console.Out);
Console.WriteLine();
Console.WriteLine("RunSparqlQuery(query, SparqlXmlQuerySink):");
source.RunSparqlQuery(query, new SparqlXmlQuerySink(Console.Out));
Console.WriteLine();
Console.WriteLine();
}
public static void Main()
{
System.Net.ServicePointManager.Expect100Continue = false; // don't send HTTP Expect: headers which confuse some servers
string endpoint = "http://www.rdfabout.com/sparql";
string ex1 = "PREFIX foaf: <http://xmlns.com/foaf/0.1/>\n"
+ "SELECT ?name \n"
+ "WHERE { [] foaf:name ?name . }\n"
+ "LIMIT 10 \n";
string ex2 = "PREFIX foaf: <http://xmlns.com/foaf/0.1/>\n"
+ "ASK \n"
+ "WHERE { [] foaf:name ?name . }\n";
string ex3 = "PREFIX foaf: <http://xmlns.com/foaf/0.1/>\n"
+ "CONSTRUCT { ?person foaf:name2 ?name } \n"
+ "WHERE { ?person foaf:name ?name . }\n"
+ "LIMIT 10 \n";
SparqlHttpSource source = new SparqlHttpSource(endpoint);
Console.WriteLine("RunSparqlQuery(ex1, Console.Out):");
source.RunSparqlQuery(ex1, Console.Out);
Console.WriteLine();
Console.WriteLine("RunSparqlQuery(ex1, SparqlXmlQuerySink):");
source.RunSparqlQuery(ex1, new SparqlXmlQuerySink(Console.Out));
Console.WriteLine();
Console.WriteLine();
Console.WriteLine("RunSparqlQuery(ex2, bool):");
bool result;
source.RunSparqlQuery(ex2, out result);
Console.WriteLine(result);
Console.WriteLine();
Console.WriteLine("RunSparqlQuery(ex3, N3Writer):");
using (N3Writer writer = new N3Writer(Console.Out))
source.RunSparqlQuery(ex3, writer);
Console.WriteLine();
Console.WriteLine("Select(subject,__,__)");
using (N3Writer writer = new N3Writer(Console.Out))
source.Select(new Statement("http://www.rdfabout.com/rdf/usgov/congress/people/M000303", null, null), writer);
Console.WriteLine();
Console.WriteLine("Query(...) A");
Variable a = new Variable("a");
QueryOptions qo = new QueryOptions();
qo.Limit = 10;
source.Query(new Statement[] {
new Statement(a, "http://xmlns.com/foaf/0.1/name", (Literal)"John McCain"),
new Statement(a, new Variable("b"), new Variable("c")),
}, qo, new SparqlXmlQuerySink(Console.Out));
Console.WriteLine();
Console.WriteLine();
Console.WriteLine("Query(...) B");
QueryResultBuffer qb = new QueryResultBuffer();
source.Query(new Statement[] {
new Statement(a, "http://xmlns.com/foaf/0.1/name", (Literal)"John McCain"),
new Statement(a, new Variable("b"), new Variable("c")),
}, qo, qb);
foreach (VariableBindings b in qb)
{
Console.WriteLine("a => " + b["a"]);
Console.WriteLine("b => " + b["b"]);
Console.WriteLine();
}
Console.WriteLine();
}
private static void ExecuteQuery(Path cache)
{
var namespaces =
new[]
{
new { Prefix = "foaf", Uri = foaf },
new { Prefix = "dbo", Uri = dbo },
new { Prefix = "dbp", Uri = "http://dbpedia.org/property/" },
new { Prefix = "skos", Uri = "http://www.w3.org/2004/02/skos/core#" },
new { Prefix = "xsd", Uri = "http://www.w3.org/2001/XMLSchema#" },
};
var attributes =
new[]
{
new { Name = "foaf:page", Variable = "page" },
new { Name = "dbo:thumbnail", Variable = "photo" },
new { Name = "foaf:name", Variable = "name" },
new { Name = "dbo:abstract", Variable = "description" },
new { Name = "dbo:birthYear", Variable = "birthYear" },
new { Name = "dbo:birthPlace", Variable = "birthPlace" },
new { Name = "dbo:deathYear", Variable = "deathYear" },
new { Name = "dbo:deathPlace", Variable = "deathPlace " },
new { Name = "dbp:children", Variable = "child " },
new { Name = "dbp:parents", Variable = "parent " },
};
Console.WriteLine("Refreshing DBpedia data...");
var query = new StringBuilder();
foreach (var @namespace in namespaces)
{
query.AppendLine(string.Format("PREFIX {0}: <{1}>", @namespace.Prefix, @namespace.Uri));
}
query.AppendLine("CONSTRUCT {");
foreach (var attribute in attributes)
{
query.AppendLine(string.Format("?person {0} ?{1} .", attribute.Name, attribute.Variable));
}
query.AppendLine("} WHERE {");
query.AppendLine("?person skos:subject <http://dbpedia.org/resource/Category:American_inventors> .");
foreach (var attribute in attributes)
{
query.AppendLine(string.Format("OPTIONAL {{ ?person {0} ?{1} . }}", attribute.Name, attribute.Variable));
}
query.AppendLine("FILTER (bound(?name) && lang(?name) = 'en') .");
query.AppendLine("FILTER (!bound(?description) || lang(?description) = 'en') .");
//query.AppendLine("FILTER (!bound(?birthYear) || datatype(?birthYear) = xsd:gYear) .");
//query.AppendLine("FILTER (!bound(?deathYear) || datatype(?deathYear) = xsd:gYear) .");
query.AppendLine("} ORDER BY ?person");
//query.AppendLine("LIMIT 20");
Console.WriteLine(query);
using (var writer = new RdfXmlWriter(cache.FullPath))
{
foreach (var @namespace in namespaces)
{
writer.Namespaces.AddNamespace(@namespace.Uri, @namespace.Prefix);
}
var source = new SparqlHttpSource("http://dbpedia.org/sparql");
source.RunSparqlQuery(query.ToString(), writer);
}
}
