Roy Tang

All entries tagged sparql.

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Dec 2016

• I tried to insert the following test document:

  db.documents.write(
      {
          uri: "/test/doc1.json",
          contentType: "application/json",
          collections: "test",
          content: {
              name : "Peter",
              hobby: "Sleeping",
              other: "Some other info",
              "triple": {
                  "subject": {   
                      "datatype": "http://example.com/name/",  
                      "value": "Peter"   
                  },   
                  "predicate": {     
                      "datatype": "http://example.com/relation/",  
                      "value": "livesin"   
                  },   
                  "object": {     
                      "datatype": "http://example.com/location/",  
                      "value": "Paris"   
                  }
            	}
          }
      }
    ).
    result(function(response){
      console.log("Done loading");
    }); 
  

  Then I queried as follows:

  var query = [
    'SELECT ?s ?p ?o' ,
    'WHERE { ?s ?p ?o }' ,
  ];
  db.graphs.sparql('application/sparql-results+json', query.join('\n')
  ).result(function (result) {
    console.log(JSON.stringify(result, null, 2));
  }, function(error) {
    console.log(JSON.stringify(error, null, 2));
  });
  

  The results showed me the values of the triple, but what if I also want to get the entire document where the triple was embedded? Is it also possible to filter by other fields in the document?

  Posted by Roy Tang under notes at 5 Dec 2016 6:44am #node.js #sparql #marklogic #questions #stackoverflow #software development
  Also on: stackexchange / 2

• I inserted a test document using the Node.js API:

    db.documents.write(
      {
          uri: "/test/doc1.json",
          contentType: "application/json",
          collections: "test",
          content: {
              name : "Peter",
              "triple": {
                  "subject": {   
                      "datatype": "http://example.com/name/",  
                      "value": "Peter"   
                  },   
                  "predicate": {     
                      "datatype": "http://example.com/relation/",  
                      "value": "livesin"   
                  },   
                  "object": {     
                      "datatype": "http://example.com/location/",  
                      "value": "Paris"   
                  }
            	}
          }
      }
    ).
    result(function(response){
      console.log("Done loading");
    }); 
  

  Then I tried querying it via SPARQL on the Marklogic console webapp:

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

  The query above works fine, it retrieves the test triple I inserted above

  However, if I want to filter by the literal value “Paris”, I tried the following:

  PREFIX loc: <http://example.com/location/>
  
  SELECT ?s ?p 
    WHERE { ?s ?p loc:Paris }
  

  But in this case I got zero results. Is this syntax incorrect? I was just following how the queries looked in https://docs.marklogic.com/guide/semantics/semantic-searches

  What is the proper way to do it?

  Posted by Roy Tang under notes at 5 Dec 2016 6:02am #sparql #marklogic #questions #stackoverflow #software development
  Also on: stackexchange / 1