SELECT ?name ?birth ?person ?subject
WHERE { ?person dbo:birthPlace :London . ?person
dbo:birthDate ?birth . ?person foaf:name ?name .
?person dct:subject :English_rock_singers. ?person dct:subject ?
subject. } ORDER BY ?name
This query works only if I delete the "subject".
Is there a way to query dbpedia with a category?
Though your question is not clear, I think your problem is with formatting the query and defining the prefixes. This should work:
PREFIX dbo: <http://dbpedia.org/ontology/>
PREFIX foaf: <http://xmlns.com/foaf/0.1/>
PREFIX dct: <http://purl.org/dc/terms/>
PREFIX dbr: <http://dbpedia.org/resource/>
PREFIX dbc: <http://dbpedia.org/resource/Category:>
SELECT ?name ?birth ?person ?subject WHERE {
?person dbo:birthPlace dbr:London.
?person dbo:birthDate ?birth.
?person foaf:name ?name.
?person dct:subject dbc:English_rock_singers.
?person dct:subject ?subject.
}
ORDER BY ?name
Related
I know this is an easy question to answer, but I have been googling this for a few hours without success. Why does the following SPARQL being entered in http://dbpedia.org/snorql/ not return anything?
prefix dbo: <http://dbpedia.org/ontology/>
SELECT ?country ?city ?city_name ?country_name
WHERE {
?city rdf:type dbo:City .
?city foaf:name ?city_name .
?city dbo:country ?country .
FILTER(?country=dbpedia:Canada).
?country foaf:name ?country_name .
}
LIMIT 200
I also tried -with the same results (i.e. none)
prefix dbo: <http://dbpedia.org/ontology/>
SELECT ?country ?city ?city_name
WHERE {
?city rdf:type dbo:City .
?city foaf:name ?city_name .
?city dbo:country ?country .
?country foaf:name ?country_name .
FILTER(langMatches(lang(?country_name),"EN") && ?country_name="Canada")
}
LIMIT 200
No need for filters for an equality.
PREFIX dbo: <http://dbpedia.org/ontology/>
PREFIX foaf: <http://xmlns.com/foaf/0.1/>
PREFIX rdf: <http://www.w3.org/1999/02/22-rdf-syntax-ns#>
SELECT ?country ?city ?city_name
WHERE {
?city rdf:type dbo:City ;
foaf:name ?city_name ;
dbo:country ?country .
?country foaf:name "Canada"#en .
FILTER(langMatches(lang(?city_name), "en"))
}
ORDER BY ?city_name
LIMIT 100
Test : http://linkedwiki.com/query/Filter_cities_by_country_with_DBpedia
Figured it out with some further digging.
To get the first query digging, I was using the wrong prefix. I needed to use <http://dbpedia.org/Resource> not the ontology one. This comes pre-defined in snorql - but it didn't actually have a prefix. But with some fiddling the following worked.
prefix dbo: <http://dbpedia.org/ontology/>
SELECT ?country ?city ?city_name ?country_name
WHERE {
?city rdf:type dbo:City .
?city foaf:name ?city_name .
?city dbo:country ?country .
FILTER(?country=:Canada).
?country foaf:name ?country_name .
}
LIMIT 200
As for matching on name, apparently you can't just match on a literal when using foaf. You need to add the language tag:
prefix dbo: <http://dbpedia.org/ontology/>
SELECT ?country ?city ?city_name
WHERE {
?city rdf:type dbo:City .
?city foaf:name ?city_name .
?city dbo:country ?country .
?country foaf:name ?country_name .
FILTER(langMatches(lang(?country_name),"EN") && ?country_name="Canada"#en)
}
LIMIT 200
I'm trying to run this Sparql statement to read data from DBpedia; However, it only return the column names and no row data.
If anybody can let me know what's the issue. I'll be more appreciated
Sparql query below:
PREFIX dbp: <http://dbpedia.org/property/>
PREFIX dc: <http://purl.org/dc/terms/>
PREFIX rdfs: <http://www.w3.org/2000/01/rdf-schema#>
PREFIX xsd: <http://www.w3.org/2001/XMLSchema#>
SELECT ?actor ?movie ?director ?movie_date
WHERE {
?m dc:subject <http://dbpedia.org/resource/Category:American_films> .
?m rdfs:label ?movie .
FILTER(LANG(?movie) = "en")
?m dbp:released ?movie_date .
FILTER(DATATYPE(?movie_date) = xsd:date)
?m dbp:starring ?a .
?a rdfs:label ?actor .
FILTER(LANG(?actor) = "en")
?m dbp:director ?d .
?d rdfs:label ?director .
FILTER(LANG(?director) = "en")
}
The problem is not all the queried triples exist. If at least one of the relations doesnt exist, no result will be given.
So with the OPTIONAL keyword, answers will be given only if they exist and wont block your query if they don't. It simply leaves the missing value empty.
PREFIX dbp: <http://dbpedia.org/property/>
PREFIX dc: <http://purl.org/dc/terms/>
PREFIX rdfs: <http://www.w3.org/2000/01/rdf-schema#>
PREFIX xsd: <http://www.w3.org/2001/XMLSchema#>
SELECT ?actor ?movie ?director ?movie_date
WHERE {
?m dc:subject <http://dbpedia.org/resource/Category:American_films> .
OPTIONAL{
?m rdfs:label ?movie .
FILTER(LANG(?movie) = "en") }
OPTIONAL {
?m dbp:released ?movie_date .
FILTER(DATATYPE(?movie_date) = xsd:date) }
OPTIONAL{
?m dbp:starring ?a .
?a rdfs:label ?actor .
FILTER(LANG(?actor) = "en") }
OPTIONAL{
?m dbp:director ?d .
?d rdfs:label ?director .
FILTER(LANG(?director) = "en") }
}
I created the following SPARQL query to Wikidata. And the result of this query are records related to states in Germany. But as you can see, results are occurring four times in a row (you can test it here: https://query.wikidata.org/). I supposed that there is a problem with geo coordinates and languages but I can't resolve it anyway. What is wrong with this query and how can I fix it to receive a result without repetition?
PREFIX p: <http://www.wikidata.org/prop/>
PREFIX schema: <http://schema.org/>
PREFIX psv: <http://www.wikidata.org/prop/statement/value/>
PREFIX wdt: <http://www.wikidata.org/prop/direct/>
PREFIX wikibase: <http://wikiba.se/ontology#>
PREFIX rdfs: <http://www.w3.org/2000/01/rdf-schema#>
PREFIX wd: <http://www.wikidata.org/entity/>
SELECT DISTINCT ?subject ?featureCode ?countryCode ?name ?latitude ?longitude ?description ?iso31662
WHERE
{ ?subject wdt:P31 wd:Q1221156 ;
rdfs:label ?name ;
wdt:P17 ?countryClass .
?countryClass
wdt:P297 ?countryCode .
?subject wdt:P31/(wdt:P279)* ?adminArea .
?adminArea wdt:P2452 "A.ADM1" ;
wdt:P2452 ?featureCode .
?subject wdt:P300 ?iso31662
OPTIONAL
{ ?subject schema:description ?description
FILTER ( lang(?description) = "en" )
?subject p:P625 ?coordinate .
?coordinate psv:P625 ?coordinateNode .
?coordinateNode
wikibase:geoLatitude ?latitude ;
wikibase:geoLongitude ?longitude
}
FILTER ( lang(?name) = "en" )
FILTER EXISTS { ?subject wdt:P300 ?iso31662 }
}
ORDER BY lcase(?name)
OFFSET 0
LIMIT 200
In short, "9.0411111111111"^^xsd:double and "9.0411111111111"^^xsd:decimal are distinct, though they might be equal in some sense.
Check this:
SELECT DISTINCT ?subject ?featureCode ?countryCode ?name ?description ?iso31662
(datatype(?latitude) AS ?lat)
(datatype(?longitude) AS ?long)
and this:
SELECT DISTINCT ?subject ?featureCode ?countryCode ?name ?description ?iso31662
(xsd:decimal(?latitude) AS ?lat)
(xsd:decimal(?longitude) AS ?long)
I created this query to return all books that are notable works by George Orwell but it returns no result.
PREFIX dbo: <http://dbpedia.org/ontology/>
PREFIX dbp: <http://dbpedia.org/resource/>
PREFIX foaf: <http://xmlns.com/foaf/0.1/>
SELECT ?name ?title where {
?person foaf:name ?name .
?title dbo:author ?person .
?title dbo:notableWork dbp:George_Orwell .
}
I cannot seem to figure out why there is no result.
I am running the query in http://dbpedia.org/snorql
Don't you have the triples about notable works in the wrong order?
Try rewriting based on this working query
SELECT *
WHERE {
:George_Orwell dbo:notableWork ?title
}
.
title
:Nineteen_Eighty-Four
:Animal_Farm
You can also bind :George_Orwell to a variable and ask more about that:
SELECT *
WHERE {
values ?author { :George_Orwell } .
?author rdfs:label ?l .
?title ?p ?author .
?title rdf:type dbo:Book .
filter (lang(?l) = "en")
}
and DESCRIBE things
describe :Animal_Farm
I am writing a federated query to get the books based on films in dbpedia and in turn using the film name from dbpedia to retrieve the corresponding imdblink link for the same. I am getting an empty set when I add the service of linkedmdb.
Here is my code
PREFIX owl: <http://www.w3.org/2002/07/owl#>
PREFIX rdfs: <http://www.w3.org/2000/01/rdf-schema#>
PREFIX movie: <http://data.linkedmdb.org/resource/movie/>
PREFIX dc: <http://purl.org/dc/terms/>
PREFIX rdf: <http://www.w3.org/1999/02/22-rdf-syntax-ns#>
PREFIX dbo: <http://dbpedia.org/ontology/>
PREFIX foaf: <http://xmlns.com/foaf/0.1/>
PREFIX dbp: <http://dbpedia.org/property/>
SELECT distinct ?name ?author ?filmname ?imdbID WHERE {
SERVICE <http://dbpedia.org/sparql> {
?book rdf:type dbo:Book .
?book foaf:name ?name .
?book dbp:author ?author .
?author foaf:name ?authname .
?book ^dbo:basedOn ?movie .
?movie a dbo:Film .
?movie foaf:name ?filmname
FILTER (str(?name) IN ("Royal Flash","White Oleander", "Possession: A Romance", "Misery", "Intensity", "The War of The Roses", "Momo", "The Sicilian", "Derailed", "Ragtime"))
}
SERVICE <http://data.linkedmdb.org/sparql> {
?filmname foaf:page ?imdbID .
?filmname dc:title ?title .
FILTER(regex(str(?imdbID), "www.imdb.com" ) )
}
}
I am using the following endpoint http://www.sparql.org/query.html
That does not work because of the ?filename variable
in the first SERVICE clause you get
?movie foaf:name ?filmname, thus, those are string literals
in the second SERVICE clause ?filmname are URIs
It will become easy to see if you run both SPARQL queries separately.
What you would have to do is to match on the title, i.e. change
?filmname dc:title ?title .
to
?filmname dc:title ?filmname .
Note, this might not work because of different types of strings, e.g. with and without language tag etc.
In that case you would have to match on the lexical form again, i.e. use temporary variables ?filmname1 and ?filmname2 and use
FILTER(str(?filmname1) = str(?filmname2))
PREFIX dbo: <http://dbpedia.org/ontology/>
PREFIX dbp: <http://dbpedia.org/property/>
PREFIX movie: <http://data.linkedmdb.org/resource/movie/>
PREFIX owl: <http://www.w3.org/2002/07/owl#>
PREFIX rdf: <http://www.w3.org/1999/02/22-rdf-syntax-ns#>
PREFIX rdfs: <http://www.w3.org/2000/01/rdf-schema#>
PREFIX foaf: <http://xmlns.com/foaf/0.1/>
PREFIX dc: <http://purl.org/dc/terms/>
SELECT DISTINCT ?name ?author ?filmname1 ?imdbID
WHERE
{ SERVICE <http://dbpedia.org/sparql>
{ ?book rdf:type dbo:Book ;
foaf:name ?name ;
dbp:author ?author .
?author foaf:name ?authname .
?book ^dbo:basedOn ?movie .
?movie rdf:type dbo:Film ;
foaf:name ?filmname1
FILTER ( str(?name) IN ("Royal Flash", "White Oleander", "Possession: A Romance", "Misery", "Intensity", "The War of The Roses", "Momo", "The Sicilian", "Derailed", "Ragtime") )
}
SERVICE <http://data.linkedmdb.org/sparql>
{ ?filmname foaf:page ?imdbID ;
dc:title ?filmname2
FILTER regex(str(?imdbID), "www.imdb.com")
}
FILTER ( str(?filmname1) = str(?filmname2) )
}