SPARQL degrees of separation - sparql

Question

Using SPARQL, how can I find entities linked to an entity by x degrees of separation, for example 4 or 5 degrees? For example, with test data like this, how do I find which of my relatives connects to which one? The aim is to form a graph from the triples. (Using only “raised” as predicates in this example, but any connection should be considered.)
<http://www.example.com/great-grandma> <:raised1> <http://www.example.com/grandma> .
<http://www.example.com/grandma> <:raised2> <http://www.example.com/ma> .
<http://www.example.com/ma> <:raised3> <http://www.example.com/me> .
<http://www.example.com/ma> <:raised4> <http://www.example.com/sis> .
<http://www.example.com/me> <:raised5> <http://www.example.com/kid> .
<http://www.example.com/spouse> <:raised6> <http://www.example.com/kid> .
So from the above, the wanted first-degree relationships would be:
<http://www.example.com/ma> <:raised3> <http://www.example.com/me> .
<http://www.example.com/me> <:raised5> <http://www.example.com/kid> .
With the whole s-p-o triple as the result.
I can get to two degrees relatively easily:
SELECT *
WHERE
{ { SELECT DISTINCT ?s ?p ?o
WHERE
{ ?s ?p1 <http://www.example.com/me> .
?s ?p ?o
}
}
UNION
{ SELECT DISTINCT ?s ?p ?o
WHERE
{ <http://www.example.com/me> ?p1 ?o .
?s ?p ?o
}
}
UNION
{ SELECT DISTINCT ?s ?p ?o
WHERE
{ ?o ?p1 <http://www.example.com/me> .
?s ?p ?o
}
}
UNION
{ SELECT DISTINCT ?s ?p ?o
WHERE
{ <http://www.example.com/me> ?p1 ?s .
?s ?p ?o
}
}
}
This finds my grandmother and sister, for example. But this does not seem practical with more degrees of separation, as the number of sub-queries would double with each new degree. Is there a better way to do this? It would need to work with larger amounts of data too, so can't just run a new query on every linked entity.
EDIT: Highlighting that different predicates should be expected, I clarified and changed the example a bit.

Answer 1

Property paths are your friend.
SELECT DISTINCT ?rel {
{
SELECT ?rel {
:me (:raised|^:raised) ?rel
}
}
UNION {
SELECT ?rel {
:me (:raised|^:raised)/(:raised|^:raised) ?rel
}
}
UNION {
SELECT ?rel {
:me (:raised|^:raised)/(:raised|^:raised)/(:raised|^:raised) ?rel
}
}
}
and so on...