SPARQL: selecting people by country

Question

I am trying to select all people born in a specific country (e.g. Portugal) from DBPedia.

I could use this query:

         SELECT DISTINCT ?person   
         WHERE {
            ?person dbpedia-owl:birthPlace dbpedia:Portugal.
          }

But the problem is that not all people have dbpedia:Portugal as birthPlace. About 30% of people have just a town name as birthPlace, e.g.

       dbpedia:Lisbon

I could add all Portugal cities in a FILTER clause but it's a big list.

May be it's possible to infer Portugal from Lisbon in the SPARQL query somehow?

(to not to add all Portugal cities in FILTER to get ALL persons)

Answer 1

If we assume all the cities in a specific country are defined as part of that country in dbpedia, you could have a query that first looks for the people that have dbpedia:Portugal as a country and then cities within dbpedia:Portugal.

SELECT DISTINCT ?person
WHERE {
    ?person a dbpedia-owl:Person.
Optional{
    ?person dbpedia-owl:birthPlace ?country.
}
Optional{
    ?person dbpedia-owl:birthPlace ?place.
    ?place dbpedia-owl:country ?country
}
filter(?country= dbpedia:Portugal)
}

The query that you have written identifies 1723 distinct URIs, and this finds 2563 URIs.