What is SPARQL

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An endpoint to play with

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select ?s2 as ?c1 count (*) as ?c2
where {
?s1 ?s1textp ?o1 .
?o1 bif:contains '"hexokinase"' .
?s1 a <http://purl.uniprot.org/core/Sequence> .
?s1 a <http://purl.uniprot.org/core/Citation_Statement> .
?s1 <http://purl.uniprot.org/core/memberOf> ?s2 .
} group by ?s2 order by desc 2 limit 20 offset 0

In a triple store, I have the label of the predicate.

Sample queries 

select *
where {?s ?p ?o}
limit 100

select ?o count(*)
where {?s a ?o}

select ?t ?p count(*)
 where {
?s ?p ?o .
?s rdf:type ?t .
?o bif:contains "hexokinase" .
}
  • bif:contains (full-text search) is not standard.
  • count(*) is not standard. 
select ?s ?p ?o
 where {
?s ?p ?o .
?o bif:contains "hexokinase" .
}

select ?s ?p ?o
 where {
?s ?p ?o .
?s ?p1 ?o1 .
?o bif:contains "hexokinase" .
}
ORDER BY (?s)

select ?s1
 where {
?s ?p ?o .
?s1 ?p1 ?s .
?o bif:contains "hexokinase" .
}

?s1 ?p1 ?s is the JOIN of SPARQL. 

select count(*) 
where { 
?s ?p ?o
}

This counts the number of triples in the database. 

select ?s count(*)
where {
?s ?p ?o
}

select ?t ?p
where {
?s a ?t .
?s ?p ?o .
}
order by ?t

select ?o1 ?p ?o2 count(*)
where {
?s1 a ?o1 .
?s2 a ?o2 .
?s1 ?p ?s2 .
FILTER (?o1 != ?o2)
}
order by desc(count(*))

books

  • Programming the semantic web