CONSTRUCT and SELECT queries return no results

[nmerkle]

Hi,

currently I try to execute CONSTRUCT and SELECT queries via the rdfstore-js library. However, if I execute the queries, the result array is empty, although there should be values.

First I load a graph into the store. In the second step, I add some triples to the loaded graph in the following way: `store.graph((err, g) => { for (let feat in featVector) { let subject = store.rdf.createNamedNode(store.rdf.resolve("wiki:HearRate")) let predicate = store.rdf.createNamedNode(store.rdf.resolve("property:HasValue")) let literal = store.rdf.createLiteral("45", undefined, store.rdf.resolve("xsd:double")) let statement = store.rdf.createTriple(subject, predicate, literal) g.add(statement) }

//Here I make SELECT Queries to the graph for (let query in stateRules) { store.execute(stateRules[query], (err, res) => { if (err == null) { res.forEach((triple) => { states.push(triple.state.value) }) } }) } })`

Regarding the literal expression: let literal = store.rdf.createLiteral("45", undefined, store.rdf.resolve("xsd:double"))

I also tried these two alternatives, since I was not sure which one of them works: let literal = store.rdf.createLiteral("45") and let literal = store.rdf.createLiteral("45"^^xsd:double)

My select queries look like the following:

SELECT ?state WHERE { ?state <http://localhost/Property-3AHasExpression> "HeartRate < 50". ?state <http://localhost/Property-3AHasObservationFeature> <http://localhost/HeartRate>. <http://localhost/HeartRate> <http://localhost//Property-3AHasValue> ?heartrate. FILTER(?heartrate < 50) }

If I put away the FILTER expression and the HasValue statement, then it works. Therefore, I think something goes wrong as I add new triple statements to the graph with the appropriate values. My questions is now, how to make it right? For instance, I could not find an example that shows how to add double value literals to the graph. Second, what do I have to change in the FILTER expression so that it works? Any hints and solutions regarding this issue are appreciated.

Best, Nicole