如何使用SPARQL在dbpedia中搜索与给定术语部分匹配的rdfs：label？

Question

I am using this query to search for all labels that contains the word "Medi"

select distinct ?label where 
{ 
    ?concept rdfs:label  ?label 
    filter contains(?label,"Medi") 
    filter(langMatches(lang(?label),"en")) 
}

However, as soon as I change the term from "Medi" to "Medicare" it doesn't work and times out. How do I get it to work with longer words like Medicare ie extract all labels which has the word Medicare in it.

Answer 1

Your query has to iterate over all labels in DBpedia - which is quite a large number - and then apply String containment check. This is indeed expensive.

Even a count query leads to an "estimated timeout error":

select count(?label) where 
{ 
    ?concept rdfs:label  ?label 
    filter(regex(str(?label),"Medi")) 
    filter(langMatches(lang(?label),"en")) 
}

Two options:

1. Virtuoso has some fulltext search support:

    SELECT DISTINCT ?label WHERE { ?concept rdfs:label ?label . ?label bif:contains "Medicare" FILTER(langMatches(lang(?label),"en")) } 

2. Since the public DBpedia endpoint is a shared endpoint, the solution is to load the DBpedia dataset into your own triple store, eg Virtuoso. There you can adjust the max. estimated execution timeout parameter.