sparql

问题 I am querying DBpedia using SPARQL through Python. I am facing issues with the upper execution time limit. This is the error : Code : sparql = SPARQLWrapper("http://dbpedia.org/sparql") newquery = "DEFINE input:inference "skos-trans" PREFIX dcterms: <http://purl.org/dc/terms/> select distinct ?cat1 ?cat2 ?cat3 ?cat4 where { <http://dbpedia.org/resource/Pulp_Fiction> dcterms:subject ?cat1 . ?cat1 skos:broaderTransitive ?cat2. ?cat2 skos:broaderTransitive ?cat3. ?cat3 skos:broaderTransitive

问题 I'd like to use Jena's inference capabilities, but I'm having some performance problems when I am using InfModel. Here's a simplified overview of my ontology: Properties: hasX (Ranges(intersection): X, inverse properties: isXOf) |-- hasSpecialX (Ranges(intersection): X, inverse properties: isSpecialXOf) isXOf (Domains(intersection): X, inverse properties: hasX) |--isSpecialXOf (Domains(intersection): X, inverse properties: hasSpecialX) Furthermore there's a class 'Object': Object hasSpecialX

问题 Is it possible to bound the length of property path? For example getting all the triples with lengths that are between (m,n) or all that are not between this range? For instance, how could this be done with the following query? select ?x ?y where {?x p* ?y} 回答1: Some endpoints support this directly Some SPARQL engines support a method for doing this directly, with a regular-expression-like syntax. E.g., ?s :p{n,m} ?o would be a path with a length between n and m. That syntax is described in

问题 Is it possible to bound the length of property path? For example getting all the triples with lengths that are between (m,n) or all that are not between this range? For instance, how could this be done with the following query? select ?x ?y where {?x p* ?y} 回答1: Some endpoints support this directly Some SPARQL engines support a method for doing this directly, with a regular-expression-like syntax. E.g., ?s :p{n,m} ?o would be a path with a length between n and m. That syntax is described in

问题 Ok so i have this query PREFIX rdfs: <http://www.w3.org/2000/01/rdf-schema#> SELECT DISTINCT (COUNT(?instance) AS ?count) WHERE { ?instance a <http://dbpedia.org/ontology/Ambassador> . } and the result is 286. Cool. Now I want to get the number of ambassadors that have http://dbpedia.org/property/name property. But PREFIX rdfs: <http://www.w3.org/2000/01/rdf-schema#> SELECT DISTINCT (COUNT(?instance) AS ?count) WHERE { ?instance a <http://dbpedia.org/ontology/Ambassador> . ?instance <http:/

问题 I can include URIs and variables in my queries, but I can't include literals in my queries. Here, I have some code which successfully reads an RDF file, finds all the RDF triples with skos:prefLabels, counts them, and then identifies a couple of specific ones from a set of keywords: import rdflib.plugins.sparql as sparql import rdflib import rdflib.graph as g graph = g.Graph() # Read the RDF file graph.parse( 'h:\......SKOSTaxonomy.rdf', format='xml') # Build and execute the query q = sparql

问题 In a previous question, a comment suggests that select ?x ?y where { {?x rdf:type ex:someType} {?x ex:someProperty ?y} } is like (not identical) to: select ?x ?y where { ?x rdf:type ex:someType. ?x ex:someProperty ?y. } Same triple patterns are used. However, the first query contains two BGPs (each one in a group pattern), while the second contains one BGP (no group patterns). The algebra for the first query is a JOIN between two BGPs while the algebra of the second is only a BGP . First

问题 i am very new to sparql and i am trying to run 3 queries on wikidata: Persons who are not painters and who are students of painters. Persons who are not painters and who are academic offspring or children of painters (note: an academic offspring of a person P is somebody who is/was a student of P , or a student of a student of P , or .... ). People who are academic offspring of themselves. i got stuck on the first one, i tried: SELECT DISTINCT ?human ?humanLabel WHERE { ?human wdt:P31 wd:Q5.

问题 I'm new to sparql and trying to fegure out what is the best way to select the max value of a counter of another query without creating a new table, only using sub-queries. I'm working on a relatively small dataset so the computation time is not a problem. SELECT ?p1 ?c1 (MAX(?cnt1) AS ?maxc) WHERE{ { SELECT ?p1 ?c1 (COUNT(?s1) AS ?cnt1) WHERE { ?s1 ?p1 ?o1; a ?c1. }Group by ?p1 ?c1 #ORDER BY ?p1 DESC(?cnt1) } }GROUP BY ?p1 so I'm expecting to get a row for every value of ?p1 with the max

问题 Suppose we have a dataset that looks like this: :person :wantsCD :cd1; :wantsCD :cd2 . :storeA :sellsCD :cd1; sellsCD :cd2; sellsCD :cd3 . :storeB :sellsCD :cd1; sellsCD :cd10; sellsCD :cd100 . I'm interested in finding the stores that sell all the CD's :person wants, i.e. ( :storeA ). Is it possible to get this result with a SPARQL query? The query should also work when the number of CD's the :person wants is unknown at runtime. I tried: SELECT DISTINCT ?store ?cd WHERE { :person :wantsCD