I am trying to query dbpedia to get some people data and I don't have subjects just names of the people I want to query and their birth/death dates.
I am trying to do a query along these lines. I want the name, birth date, death date and thumbnail of everyone with the surname Presley. What I then intend to do is loop through the results returned and find the best match for Elvis Presley 1935-1977 which is the data I have.
PREFIX dbo: <http://dbpedia.org/ontology/>
SELECT ?Name ?thumbnail ?birthDate ?deathDate WHERE {
{
dbo:name ?Name ;
dbo:birthDate ?birthDate ;
dbo:birthDate ?deathDate ;
dbo:thumbnail ?thumbnail ;
FILTER contains(?Name#en, "Presley")
}
What is the best way to construct my sparql query?
UPDATE:
I have put together this query which seems to work to some extent but I don't entirely understand it, and I can't figure out the contains, but it does at least run and return results.
PREFIX rdf: <http://www.w3.org/1999/02/22-rdf-syntax-ns#>
PREFIX foaf: <http://xmlns.com/foaf/0.1/>
PREFIX dbo: <http://dbpedia.org/ontology/>
SELECT ?subject ?thumbnail ?birthdate ?deathdate WHERE {
{
?subject rdfs:label "Elvis Presley"#en ;
dbo:thumbnail ?thumbnail ;
dbo:birthDate ?birthdate ;
dbo:deathDate ?deathdate ;
a owl:Thing .
}
UNION
{
?altName rdfs:label "Elvis Presley"#en ;
dbo:thumbnail ?thumbnail ;
dbo:birthDate ?birthdate ;
dbo:deathDate ?deathdate ;
dbo:wikiPageRedirects ?s .
}
}
Some entities might not have all of that information, so it's better to use optional. You can use foaf:surname to check for surname directly.
select * where {
?s foaf:surname "Presley"#en
optional { ?s dbo:name ?name }
optional { ?s dbo:birthDate ?birth }
optional { ?s dbo:deathDate ?death }
optional { ?s dbo:thumbnail ?thumb }
}
Related
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'm developing my own Fuseki endpoint from some DBpedia data.
I'm in doubt on how to aggregate properties related to a single resource.
SELECT ?name ?website ?abstract ?genre ?image
WHERE{
VALUES ?s {<http://dbpedia.org/resource/Attack_Attack!>}
?s foaf:name ?name ;
dbo:abstract ?abstract .
OPTIONAL { ?s dbo:genre ?genre } .
OPTIONAL { ?s dbp:website ?website } .
OPTIONAL { ?s dbo:image ?image } .
FILTER LANGMATCHES(LANG(?abstract ), "en")
}
SPARQL endpoint: http://dbpedia.org/sparql/
This query returns 2 matching results. They are different just for the dbo:genre value. There is a way I can query the knowledge base and retrieving a single result with a list of genres?
#chrisis's query works well on the DBpedia SPARQL Endpoint, which is based on Virtuoso.
However, if you are using Jena Fuseki, you should use more conformant syntax:
PREFIX dbo: <http://dbpedia.org/ontology/>
PREFIX dbp: <http://dbpedia.org/property/>
SELECT
?name
(SAMPLE(?website) AS ?sample_website)
(SAMPLE(?abstract) AS ?sample_abstract)
(SAMPLE(?image) AS ?sample_image)
(GROUP_CONCAT(?genre; separator=', ') AS ?genres)
WHERE {
VALUES (?s) {(<http://dbpedia.org/resource/Attack_Attack!>)}
?s foaf:name ?name ;
dbo:abstract ?abstract .
OPTIONAL { ?s dbo:genre ?genre } .
OPTIONAL { ?s dbp:website ?website } .
OPTIONAL { ?s dbo:image ?image} .
FILTER LANGMATCHES(LANG(?abstract ), "en")
} GROUP BY ?name
The differences from the #chrisis's query are:
Since GROUP_CONCAT is an aggregation function, it might be used with GROUP BY only;
Since GROUP BY is used, all non-grouping variables should be aggregated (e.g. via SAMPLE);
GROUP_CONCAT syntax is slightly different.
In Fuseki, these AS in the projection are in fact superfluous: see this question and comments.
Yes, the GROUP_CONCAT() function is what you want.
SELECT ?name ?website ?abstract (GROUP_CONCAT(?genre,',') AS ?genres) ?image
WHERE{
<http://dbpedia.org/resource/Attack_Attack!> a dbo:Band ;
foaf:name ?name;
dbo:abstract ?abstract .
OPTIONAL{ <http://dbpedia.org/resource/Attack_Attack!> dbo:genre ?genre } .
OPTIONAL{ <http://dbpedia.org/resource/Attack_Attack!> dbp:website ?website} .
OPTIONAL{ <http://dbpedia.org/resource/Attack_Attack!> dbo:image ?image} .
FILTER LANGMATCHES(LANG(?abstract ), "en")
}
I have to use this Spaql query to retrive information about a person, my problem is to break the optional construct up into multiple optional constructs.
PREFIX rdfs: <http://www.w3.org/2000/01/rdf-schema#>
PREFIX dbo: <http://dbpedia.org/ontology/>
PREFIX dbpprop: <http://dbpedia.org/property/>
PREFIX foaf: <http://xmlns.com/foaf/0.1/>
SELECT DISTINCT ?label ?abstract ?placeOfBirth
?birthPlace ?birthDate ?page ?thumbnail
WHERE {
<http://dbpedia.org/resource/Ismail_Kadare> rdfs:label ?label ;
dbo:abstract ?abstract ;
foaf:page ?page .
OPTIONAL {
<http://dbpedia.org/resource/Ismail_Kadare> dbpprop:placeOfBirth ?placeOfBirth ;
dbpprop:birthPlace ?birthPlace ;
dbo:birthDate ?birthDate ;
dbo:thumbnail ?thumbnail .
}
FILTER (LANG(?label) = 'en')
FILTER (LANG(?abstract) = 'en')
}
LIMIT 1
Splitting the OPTIONAL pattern into parts
The pattern
<http://dbpedia.org/resource/Ismail_Kadare> dbpprop:placeOfBirth ?placeOfBirth ;
dbpprop:birthPlace ?birthPlace ;
dbo:birthDate ?birthDate ;
dbo:thumbnail ?thumbnail .
is shorthand for four triple patterns:
<http://dbpedia.org/resource/Ismail_Kadare> dbpprop:placeOfBirth ?placeOfBirth .
<http://dbpedia.org/resource/Ismail_Kadare> dbpprop:birthPlace ?birthPlace .
<http://dbpedia.org/resource/Ismail_Kadare> dbo:birthDate ?birthDate .
<http://dbpedia.org/resource/Ismail_Kadare> dbo:thumbnail ?thumbnail .
Instead of OPTIONAL { …first pattern… }, you just need to use four optional blocks, one for each of the four triple patterns:
optional { <http://dbpedia.org/resource/Ismail_Kadare> dbpprop:placeOfBirth ?placeOfBirth }
optional { <http://dbpedia.org/resource/Ismail_Kadare> dbpprop:birthPlace ?birthPlace }
optional { <http://dbpedia.org/resource/Ismail_Kadare> dbo:birthDate ?birthDate }
optional { <http://dbpedia.org/resource/Ismail_Kadare> dbo:thumbnail ?thumbnail }
Other issues
It's worth nothing that language matching is a bit more complicated than string matching, so rather than
FILTER (LANG(?label) = 'en')
FILTER (LANG(?abstract) = 'en')
you should really be using
filter(langMatches(lang(?label),'en'))
filter(langMatches(lang(?abstract),'en'))
which allows you to retrieve results that use different language tags that are all English.
select distinct and limit 1 aren't both necessary
Notice that select distinct ensures that you don't have any duplicate rows in your results. However, limit 1 means that you'll only have one result at most anyhow, so there won't be any duplicates to remove.
Standard Namespaces
It looks like you're querying against DBpedia, so it might be worthwhile to use the same namespace prefixes that the public endpoint defines, so that you can copy and paste queries and experiment more easily. Doing that (and using a values ?x { dbpedia:Ismail_Kadare } to avoid some typing, we end up with this query:
select ?label ?abstract ?placeOfBirth ?birthPlace ?birthDate ?page ?thumbnail
where {
values ?x { dbpedia:Ismail_Kadare }
?x rdfs:label ?label ;
dbpedia-owl:abstract ?abstract ;
foaf:page ?page .
optional { ?x dbpprop:placeOfBirth ?placeOfBirth }
optional { ?x dbpprop:birthPlace ?birthPlace }
optional { ?x dbpedia-owl:birthDate ?birthDate }
optional { ?x dbpedia-owl:thumbnail ?thumbnail }
filter langMatches(lang(?label),'en')
filter langMatches(lang(?abstract),'en')
}
limit 1
The DBpedia endpoint won't return anything for that query, but that's because http://dbpedia.org/resource/Ismail_Kadare doesn't have a foaf:page property, not because the query is malformed. I don't know whether you're actually running this against DBpedia or not, so that may or not matter.
I created a SPARQL query that I'm running on the DBpedia SNORQL SPARQL endpoint. The purpose of the query is to get a list of universities or colleges in the United States, including their longitude, latitude, and endowment. The query seems to be working but seems to be missing some records and/or attributes. So, for example, Harvard University doesn't show up in the result, even though its DBpedia record exists and the attributes should match my query. I'm not sure why that record doesn't show up. Another example is University of Massachusetts Boston, which comes up as a query result, but the result doesn't get the longitude and latitude attributes, even though the record contains those attributes. Here's the SPARQL Query:
PREFIX geo: <http://www.w3.org/2003/01/geo/wgs84_pos#>
PREFIX d: <http://dbpedia.org/ontology/>
SELECT ?uni ?link ?lat ?long ?endowment
WHERE {
?s foaf:homepage ?link ;
rdf:type <http://schema.org/CollegeOrUniversity> ;
rdfs:label ?uni
OPTIONAL {?s geo:lat ?lat ;
geo:long ?long .
?s d:endowment ?endowment . }
FILTER (LANGMATCHES(LANG(?uni), 'en'))
{?s dbpedia2:country "U.S."#en . }
UNION
{?s dbpedia2:country "U.S." . }
UNION
{?s d:country :United_States . }
}
ORDER BY ?s
The query you posted will only select entities with a foaf:homepage and Harvard University does not have one. (That is, the resource does not have a foaf:homepage property. Obviously the university does have a homepage.) UMass Boston doesn't match the optional pattern --
OPTIONAL {?s geo:lat ?lat ;
geo:long ?long .
?s d:endowment ?endowment . }
-- because that pattern only matches when ?s has a geo:lat, a geo:long, and a d:endowment. Though the pattern is optional, the whole pattern must either match or not; you do not get partial matches.
Here's your query, reworked to use the built-in namespaces that the DBPedia SPARQL endpoint currently supports (that list is subject to change over time), with the OPTIONAL parts broken down as necessary, and moved to the end. (Moving them to the end is just an aesthetic consideration.) I tried some various constraints, and it is interesting to note that only 32 universities have the dbpprop:country "U.S."#en, but 273 have dbpprop:country "United States"#en. There are 7620 results in total.
PREFIX dbpedia-owl: <http://dbpedia.org/ontology/>
PREFIX dbpedia: <http://dbpedia.org/resource/>
PREFIX dbpprop: <http://dbpedia.org/property/>
SELECT ?label ?homepage ?lat ?long ?endowment
WHERE {
?school a <http://schema.org/CollegeOrUniversity>
{ ?school dbpedia-owl:country dbpedia:United_States }
UNION
{ ?school dbpprop:country dbpedia:United_States }
UNION
{ ?school dbpprop:country "U.S."#en }
UNION
{ ?school dbpprop:country "United States"#en }
OPTIONAL { ?school rdfs:label ?label .
FILTER (LANGMATCHES(LANG(?label), 'en')) }
OPTIONAL { ?school foaf:homepage ?homepage }
OPTIONAL { ?school geo:lat ?lat ; geo:long ?long }
OPTIONAL { ?school dbpedia-owl:endowment ?endowment }
}
SPARQL Results
You are looking for foaf:homepage but some of them do not have this assigned. That is the first thing that caught my eyes. Check the rest of the query by removing bit by bit each element and see what the result set has to offer.