Sparql DBPedia not returning foaf:name query

Question

I am using the Virtuoso SPARQL endpoint for DBpedia. I am having no issue running some test queries, but my issue is when I run on a query based on the foaf:name "literal" of an entity. Here is my code below:

prefix db: <http://dbpedia.org/resource/>
prefix dbo: <http://dbpedia.org/ontology/>
prefix foaf: <http://xlms.com/foaf/0.1/>

SELECT ?capital WHERE{
        ?state dbo:capital ?capital .
        ?state foaf:name "State of Alaska"@en .
        }

My logic is that by ?state dbo:capital ?capital refers to the capital of a state within DBpedia owl ontology. ?state foaf:name "State of Alaska"@en should match the variable ?state up with the literal entity Alaska . I am having no issue when my queries are controlled by variables that are not foaf:name . I have looked up examples and can't see what the issue is with my syntax. Even when I edit the last line to --

?state a foaf:name "State of Alaska"@en .

-- the code continues to fail. I have looked up other examples and can't find my specific issue. It appears as if this code SHOULD return the capital for Alaska based on the foaf:name Literal.

Answer 1

I found the answer. The key is to not add this prefix at the top

prefix foaf: <http://xlms.com/foaf/0.1/> 

That should be replaced with the correct foaf: prefix declaration:

prefix foaf: <http://xmlns.com/foaf/0.1/> 

Or probably even skipped, since the foaf: prefix is predefined .

So the query below actually works:

SELECT ?capital WHERE {
        ?state dbo:capital ?capital .
        ?state foaf:name "State of Alabama"@en .
}