How to find the composedBy relation in dbpedia? - sparql

Question

Look at this query:
construct {?symphony dct:composedBy <http://dbpedia.org/resource/Category:Symphonies_by_Ludwig_van_Beethoven>}
{
?symphony dct:subject <http://dbpedia.org/resource/Category:Symphonies_by_Ludwig_van_Beethoven>
}
You can run it over this endpoint:
http://dbpedia.org/sparql/
You will get results, so far so good:
I tried to get the music work for Beethoven by using the dct:subject, well ... that's no so correct, because it lists just the symphonies, there should be a relation to list all the works for Beethoven, including sonatas and strings ... do you know that property please?
Plus, I tried the subject property on some opera composers and the results were films that use the opera's opening for that composer as the theam for that movie. so we can see that the subject property is not good to get the musical works, i am looking for help to find something like composed by

Answer 1

here should be a relation to list all the works for Beethoven, including sonatas and strings
I don't see why that's necessarily the case; DBpedia only contains what people put into it, and that information, even if it's present in Wikipedia, isn't necessarily stored in a way that DBpedia can extract it.
It looks like you've got a reasonably good handle on how to explore DBpedia data, though, and that same kind of process can be helpful here. But if you're interested in what links to Beethoven, then you can have a look at the corresponding resources. This may have varied results.
For instance, if you look at the resource for Für Elise, you'll see there's no property directly linking it to the composer (and since those pages show properties in the reverse direction, too, there's no link from Beethoven to the piece, either). That's enough to show that DBpedia doesn't necessarily have the data you're looking for.
However, there is a property that might be useful, dct:subject dbc:Compositions_by_Ludwig_van_Beethoven. Based on that, you might be able to modify your query to use something like:
?symphony dct:subject dbc:Compositions_by_Ludwig_van_Beethoven
That's no guarantee, but this process of exploring the data looking for relevant bits is probably the best bet for finding this information.