Hi,
Having a look on this SPARQL query:
---------------------------------------------------------------------------
prefix dbo:<http://dbpedia.org/ontology/>
prefix dbr:<http://dbpedia.org/resource/>
prefix foaf:<http://xmlns.com/foaf/0.1/>
SELECT DISTINCT ?name ?birth ?death
WHERE { ?person dbo:birthPlace dbr:Berlin .
?person dbo:birthDate ?birth .
?person foaf:name ?name .
OPTIONAL { ?person dbo:deathDate ?death . }
FILTER (?birth < "1900-01-01") .
}
LIMIT 100
-----------------------------------------------------------------------------
Using Apache Jena ARQ command, ./arq --query exampleQuery.sparql --explain
I got this result.
13:11:41 INFO exec :: ALGEBRA
(slice _ 100
(distinct
(project (?name ?birth ?death)
(conditional
(sequence
(filter (< ?birth "1900-01-01")
(bgp
(triple ?person <http://dbpedia.org/ontology/birthPlace> <
http://dbpedia.org/resource/Berlin>)
(triple ?person <http://dbpedia.org/ontology/birthDate>
?birth)
))
(bgp (triple ?person <http://xmlns.com/foaf/0.1/name> ?name)))
(bgp (triple ?person <http://dbpedia.org/ontology/deathDate>
?death))))))
13:11:41 INFO exec :: BGP
?person <http://dbpedia.org/ontology/birthPlace> <
http://dbpedia.org/resource/Berlin>
?person <http://dbpedia.org/ontology/birthDate> ?birth
13:11:41 INFO exec :: Reorder/generic
?person <http://dbpedia.org/ontology/birthPlace> <
http://dbpedia.org/resource/Berlin>
?person <http://dbpedia.org/ontology/birthDate> ?birth
13:11:41 INFO exec :: BGP :: ?person <
http://xmlns.com/foaf/0.1/name> ?name
------------------------
| name | birth | death |
========================
------------------------ I have a question about the Basic Graph Patterns.
I think, in this query there are two BGPs. But here i shows 3. Can anyone
explain it to me? Also, I want to know, the number of joins, no of
projection variables, number of left joins, depth, and such other relevant
info about the query features. How can I get all at one place?
Best Regards,
*Hashim Khan*
