Java SPARQL Select query

Question

I wrote a SELECT statement that returns me all data from the fuseki-server. My question is how I can get a list with all names available below the o column (see the attached image)?

For example, I need an array that will contain the following items: [Pavel Ionut, Cirstea Aurel, Test1]

This is my SELECT statement, which should be changed to return only the name property ... but I did not use SPARQL before and any solution would help me a lot.

QueryExecution qe = QueryExecutionFactory.sparqlService(
        "http://localhost:3030/Date/query", "SELECT * WHERE {?s ?p ?o}");
ResultSet results = qe.execSelect();
ResultSetFormatter.out(System.out, results);
qe.close();
System.out.println(results);

Please start with a SPARQL tutorial. It doesn't make sense that people provide you the query now without you understanding the *why* and *how* - next time you will need another query and have to ask here again. SPARQL is not difficult to learn — UninformedUser, Apr 23 '17 at 19:04

Jens Piegsa · Accepted Answer · 2017-04-23T18:35:25.203

2

To return the set of objects from all existing s-p-o triples use this SPARQL query:

SELECT DISTINCT ?o WHERE { ?s ?p ?o . }

To only get the names, try:

PREFIX dc: <http://purl.org/dc/elements/1.1/>
SELECT DISTINCT ?n WHERE { ?s dc:name ?n . }

or just:

SELECT DISTINCT ?n WHERE { ?s <http://purl.org/dc/elements/1.1/name> ?n . }

The specification contains some good examples:

https://www.w3.org/TR/sparql11-query/

To iterate over the result set of the query above with Apache Jena Fuseki in Java, this might work:

while (results.hasNext()) {
    QuerySolution querySolution = results.next();
    RDFNode node = querySolution.get("n");
    String name = node.asLiteral().getString();
    System.out.println(name);
}

edited Apr 23 '17 at 18:35

answered Apr 23 '17 at 18:00

Jens Piegsa

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Thank you, but how can I get only the names? – Laura Cîrstea Apr 23 '17 at 18:04
That works! Do you also know how can I loop through each name using Java? – Laura Cîrstea Apr 23 '17 at 18:22
1

@LauraCîrstea I currently can not test this in code, but maybe it works. – Jens Piegsa Apr 23 '17 at 18:36

score 0 · Answer 2 · edited May 23 '17 at 10:31

0

You need to identify what the same you queried in your query. More detail you can find here:

exploratory SPARQL queries?

edited May 23 '17 at 10:31

Community

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answered Apr 23 '17 at 17:11

Vasyl Lyashkevych

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Can you be more explicit, please? – Laura Cîrstea Apr 23 '17 at 17:15
here you can identify what the same you want SELECT ?s ?p ?o – Vasyl Lyashkevych Apr 23 '17 at 17:23
and later from where: – Vasyl Lyashkevych Apr 23 '17 at 17:23
SELECT ?s ?p ?o WHERE { ?Srule Answer:rule_s ?s. ?Prule Answer:rule_p ?p. ?Orule Answer:rule_o ?o. } – Vasyl Lyashkevych Apr 23 '17 at 17:26
"Person test" must be defined by " s " "Pavel Ionut", etc must be defined by " o" – Vasyl Lyashkevych Apr 23 '17 at 17:29
Ok, but how can I get all names, like "Pavel Ionut, Cirstea Aurel, Test1" – Laura Cîrstea Apr 23 '17 at 18:00

Java SPARQL Select query

2 Answers2