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*