Hi all,
I need to query DBpedia to get the genre and release date of all the songs
that got picked in the BBC Radio 4 Desert Island Discs show. I'm using the
Jena API, in Java, to send all the SPARQL queries to the
http://dbpedia.org/sparql endpoint. Because I only have the title of the
songs and the name of the artist, I need to query by these strings. To
restrict the search, I've added the constraints on the resource type. If I
don't put a type constraint, the query times out. Here is one of the
queries I use for getting the song URI, genre and release date:
SELECT DISTINCT *
WHERE {
{
?song rdf:type <http://dbpedia.org/ontology/Single> .
?song rdfs:label ?songTitle .
OPTIONAL {?song dbpedia-owl:genre ?genre} .
OPTIONAL {?song dbpedia2:genre ?genre} .
OPTIONAL {?song dbpedia-owl:releaseDate ?releaseDate} .
FILTER ( regex(?songTitle, "Fallen Soldier", "i") ) .
FILTER (LANG(?songTitle) = 'en') .
}
UNION {
?song rdf:type <http://dbpedia.org/ontology/MusicalWork> .
?song rdfs:label ?songTitle .
OPTIONAL {?song dbpedia-owl:genre ?genre} .
OPTIONAL {?song dbpedia2:genre ?genre} .
OPTIONAL {?song dbpedia-owl:releaseDate ?releaseDate} .
FILTER ( regex(?songTitle, "Fallen Soldier", "i") ) .
FILTER (LANG(?songTitle) = 'en') .
}
UNION {
?song rdf:type <http://dbpedia.org/ontology/Work> .
?song rdfs:label ?songTitle .
OPTIONAL {?song dbpedia-owl:genre ?genre} .
OPTIONAL {?song dbpedia2:genre ?genre} .
OPTIONAL {?song dbpedia-owl:releaseDate ?releaseDate} .
FILTER ( regex(?songTitle, "Fallen Soldier", "i") ) .
FILTER (LANG(?songTitle) = 'en') .
}
UNION {
?song rdf:type <http://umbel.org/umbel/rc/MusicalComposition> .
?song rdfs:label ?songTitle .
OPTIONAL {?song dbpedia-owl:genre ?genre} .
OPTIONAL {?song dbpedia2:genre ?genre} .
OPTIONAL {?song dbpedia-owl:releaseDate ?releaseDate} .
FILTER ( regex(?songTitle, "Fallen Soldier", "i") ) .
FILTER (LANG(?songTitle) = 'en') .
}
} LIMIT 1
I've also tried to split the query into two: first to get the song URI by
title, and then get the genre and release date (which is a bit faster than
this one, but still very slow; sometimes it times out as it is.. ).
My question is, is there any way to optimize this search by literals ? It
takes up to 5 minutes per song to return results and I need to handle about
14,000 of them.
Thanks in advance!
Regards,
Alina Elena Băluşescu
MSc student in Advanced Computer Science department
The University of Manchester
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