Filtering DBpedia disambiguation page - sparql

Question

I have a SPARQL Query, and I want to eliminate all disambigution resources. How can I do this? This is my query:
prefix rdf:<http://www.w3.org/1999/02/22-rdf-syntax-ns#>
prefix rdfs: <http://www.w3.org/2000/01/rdf-schema#>
prefix foaf: <http://xmlns.com/foaf/0.1/>
select distinct ?Nom ?resource ?url where {
?resource rdfs:label ?Nom.
?resource foaf:isPrimaryTopicOf ?url.
FILTER (langMatches( lang(?Nom), "EN" )).
?Nom <bif:contains> "Apple".
}

Answer 1

You can add the following prefix and filter to your query:
prefix dbo: <http://dbpedia.org/ontology/>
filter not exists {
?resource dbo:wikiPageRedirects*/dbo:wikiPageDisambiguates ?dis
}
This says to exclude resources and resources that redirect to a resources that disambiguate some articles. That gives you a query like this:
prefix rdf:<http://www.w3.org/1999/02/22-rdf-syntax-ns#>
prefix rdfs: <http://www.w3.org/2000/01/rdf-schema#>
prefix foaf: <http://xmlns.com/foaf/0.1/>
prefix dbo: <http://dbpedia.org/ontology/>
select distinct ?Nom ?resource ?url where {
?resource rdfs:label ?Nom.
?resource foaf:isPrimaryTopicOf ?url.
FILTER (langMatches( lang(?Nom), "EN" )).
?Nom <bif:contains> "Apple".
filter not exists {
?resource dbo:wikiPageRedirects*/dbo:wikiPageDisambiguates ?dis
}
}
SPARQL results
Now, even though that removes all the disambiguation pages, you may still have results that include "disambiguation" in the title. For instance, one of the results is:
The Little Apple (disambiguation)"#en
http://dbpedia.org/resource/The_Little_Apple_(disambiguation)
Even though that has "disambiguation" in the name, it's not a disambiguation page. It doesn't have any values for dbo:wikiPageDisambiguates. it does redirect to another page, though. You may want to filter out things that redirect to something else, too. You can modify the filter though:
filter not exists {
?resource dbo:wikiPageRedirects|dbo:wikiPageDisambiguates ?dis
}
That says to filter out any resource that either redirects to something, or that disambiguates something. This is actually a simpler filter, really. This makes your query:
prefix rdf:<http://www.w3.org/1999/02/22-rdf-syntax-ns#>
prefix rdfs: <http://www.w3.org/2000/01/rdf-schema#>
prefix foaf: <http://xmlns.com/foaf/0.1/>
prefix dbo: <http://dbpedia.org/ontology/>
select distinct ?Nom ?resource ?url where {
?resource rdfs:label ?Nom.
?resource foaf:isPrimaryTopicOf ?url.
FILTER (langMatches( lang(?Nom), "EN" )).
?Nom <bif:contains> "Apple".
filter not exists {
?resource dbo:wikiPageRedirects|dbo:wikiPageDisambiguates ?dis
}
}
SPARQL results