antoniogarrote/rdfstore-js reusing blank node

Question

I am using rdfstore in nodejs and I cannot figure out how to reuse Blank nodes. I need to use blank node more then just once.

Here is the code:

graph.add(rdf.createTriple(
   new rdf.api.BlankNode(id);
   rdf.createNamedNode(predicate)
   rdf.createBlankNode()
);

id is taken from previously entered blankNode "_:30" => "30"

I have checked created blank node and it is correct (with correct id). But when I look into db it has wrong one. It seems to be using some counter even I give him exact node.

EDIT 1

I have checked created triple and it looks as I want it. So problem must be somewhere in adding triple into graph/storing the triple.

Thanks for any help,

Michal.

Answer 1

The reason is actually simple: Each call to rdfstore.Store.insert creates a SPARQL INSERT statement. And each separate SPARQL statement has its own set of unique blank nodes.

That said, the only solution for our problem is to collect the triples to add in an array and finally add them all in one go.

var triples = [];
[...]
store.insert(store.rdf.createGraph(triples), 
  graph, 
  function(success, cnt) {
    if(success) console.log(cnt + ' triples successfully added.');
  });

I hope this helps.