Retrieving properties of redirected resource - sparql

How can I retrieve all the properties of http://dbpedia.org/resource/Milano? I tried with this query but I have a few results and I don't understand the reason:
select ?prop ?c
where {<http://dbpedia.org/resource/Milano> ?prop ?c.}
SPARQL results

The question isn't entirely clear, but expect that the problem you're asking about is why you're getting triples about dbpedia:Milano, but not dbpedia:Milan. This query, as you can see in the results, only returns ten rows:
select ?prop ?c
where {
<http://dbpedia.org/resource/Milano> ?prop ?c.
}
SPARQL results
One of those rows, however, is
prop c
http://dbpedia.org/ontology/wikiPageRedirects http://dbpedia.org/resource/Milan
So, the simple answer is "query for Milan" with a query like this:
select ?prop ?c
where {
<http://dbpedia.org/resource/Milan> ?prop ?c. # you can use dbpedia:Milan, too
}
SPARQL results
A more sophisticated answer would return the triples for dbpedia:Milano and any triples of anything that it redirects to (and, I suppose, anything that any of those redirect to, and so on, though I think that Wikipedia limits redirects to be one level deep). You can do this with a property path query in SPARQL:
select ?prop ?c
where {
dbpedia:Milano dbpedia-owl:wikiPageRedirects* ?subject .
?subject ?prop ?c.
}
SPARQL results
In that query ?subject will be anything related by a path of length zero or more (so, given the data that we've seen, ?subject will be bound to at least dbpedia:Milano and dbpedia:Milan. If you want to preserve information about the subject of the various triples that you're using, you might want to add ?subject to the select line, so as to have select ?subject ?prop ?c.
If you don't care about the particular value of ?subject, then you actually don't need to bind ?subject at all, and could use a blank node in the query:
select ?prop ?c
where {
dbpedia:Milano dbpedia-owl:wikiPageRedirects* [ ?prop ?c ] .
}
SPARQL results
Caveat
Unfortunately, although this last query is legal SPARQL, Virtuoso says it's an error. Fortunately, this last refinement is entirely optional; it's not vital to the solution. If you were querying against a different endpoint, you'd be able to use it. The error that Virtuoso gives is:
Virtuoso 37000 Error SP031: SPARQL compiler: Object of transitive triple pattern should be variable or QName or literal, not blank node
SPARQL query:
define sql:big-data-const 0
#output-format:text/html
define sql:signal-void-variables 1 define input:default-graph-uri <http://dbpedia.org> select ?prop ?c
where {
dbpedia:Milano dbpedia-owl:wikiPageRedirects* [ ?prop ?c ] .
}
I contacted the Virtuoso mailing list and they confirmed that it's a Virtuoso bug, and that they'll fix it. I don't know how long it will take for the fix to get to the DBpedia endpoint, though.

Related

How to get 'is dct:subject of' property from dbpedia using SPARQL [duplicate]

I am using the following query :
select ?value where { <http://dbpedia.org/resource/Paris> dbpedia-owl:wikiPageRedirects* ?value }
in order to retrieve the wikiPageRedirects property of Paris.
Based on dbpedia Paris has more than 20 redirect links. Why am I only retrieving the first one?
Your direction was wrong.
select distinct *
where {
?x dbpedia-owl:wikiPageRedirects <http://dbpedia.org/resource/Paris>
}
Artemis's answer is right; the "direction" in the query is wrong. It's worth explaining that a bit more, though. On the DBpedia "page", you'll see lots of data like:
dbpedia-owl:area 105400000.000000 (xsd:double)
dbpedia-owl:country dbpedia:France
dbpedia-owl:inseeCode 75056 (xsd:integer)
dbpedia-owl:mayor dbpedia:Anne_Hidalgo
These mean that DBpedia contains triples where these are the predicates and objects. That is, DBpedia contains a triple:
dbpedia:Paris dbpedia-owl:country dbpedia:France
On other hand, you'll also see things like "is … of":
is dbpedia-owl:beatifiedPlace of dbpedia:Daniel_Brottier
is dbpedia-owl:billed of dbpedia:René_Duprée
These mean that dbpedia:Paris the object of triples with these subjects and predicates. E.g., DBpedia contains the triple
dbpedia:René_Duprée dbpedia-owl:billed dbpedia:Paris
The redirects properties that you're seeing are like this:
is dbpedia-owl:wikiPageRedirects of dbpedia:City_of_Love_(city)
dbpedia:Département_de_Paris
dbpedia:Departement_de_Paris
dbpedia:FRPAR
That means that there are a bunch of triples of the form:
?something dbpedia-owl:wikiPageRedirects dbpedia:Paris
and that means that your query needs to be
select ?resource where {
?resource dbpedia-owl:wikiPageRedirects dbpedia:Paris
}
SPARQL results

DBpedia Sparql by page template

I am trying to run a query on dbpedia using SPARQL syntax, to look for all pages of a certain template. Doesn't seem to be work, I am looking for all pages with dbpprop:wikiPageUsesTemplate. Does anyone know how to correct this to properly look for templates?
SELECT ?name ?member_Of ?country ?lat ?lng ?link
WHERE {
?x dbpprop:wikiPageUsesTemplate "dbpedia:Template:Infobox_settlement" .
?x a <http://dbpedia.org/ontology/Settlement> .
?x foaf:name ?name .
?x dbpedia-owl:isPartOf ?member_Of.
?x dbpedia-owl:country ?country.
?x geo:lat ?lat .
?x geo:long ?lng .
?x foaf:isPrimaryTopicOf ?link .
}
LIMIT 2500 OFFSET 0
I've also attempted to run it just by the dbprop to no avail.
SELECT * WHERE { ?page dbpprop:wikiPageUsesTemplate <http://dbpedia.org/resource/Template:Infobox_settlement> . ?page dbpedia:name ?name .}
If anyone is trying to do a similar thing, it is also possible via the wiki api, where you can pagananate over all results. http://en.wikipedia.org/w/api.php?action=query&list=embeddedin&eititle=Template:Infobox_settlement
There are at least two problems: (i) you need to use IRIs in places, and not strings; and (ii) you need to use properties that DBpedia uses.
Use IRIs
In
?x a <http://dbpedia.org/ontology/Settlement> .
and
?x foaf:isPrimaryTopicOf ?link .
you've demonstrated that you know that URIs need to be written in full with < and >, or abbreviated with a prefix. However,
?x dbpprop:wikiPageUsesTemplate "dbpedia:Template:Infobox_settlement" .
certainly isn't going to work. It's legal SPARQL, because a string can be the object of a triple, but you almost certainly want an IRI.
Use DBpedia's vocabulary
A query with dbpprop:wikiPageUsesTemplate like this returns no results:
select distinct ?template where {
[] dbpprop:wikiPageUsesTemplate ?template
}
SPARQL results
That's easy enough to check, and quickly confirms that there's no data that can possibly match your query. Where did you find this property? Have you seen it used somewhere? I'm not confident that you can query DBpedia based on infobox templates. DBpedia is not the same as Wikipedia, and even if the Wikipedia API supports it, it doesn't mean that DBpedia has a counterpart. There is a note on DBpedia Data Set Properties that says:
http://xx.dbpedia.org/property/wikiPageUsesTemplate (will be changed to http://dbpedia.org/ontology/wikiPageUsesTemplate)
but that latter property doesn't seem to be in use on the endpoints either. See my answer to Syntax for Sparql query for pages with specific infobox for more details.

Sparql to recover the Type of a DBpedia resource

I need a Sparql query to recover the Type of a specific DBpedia resource. Eg.:
pt.DBpedia resource: http://pt.dbpedia.org/resource/Argentina
Expected type: Country (as can be seen at http://pt.dbpedia.org/page/Argentina)
Using pt.DBpedia Sparql Virtuoso Interface (http://pt.dbpedia.org/sparql) I have the query below:
PREFIX rdf: <http://www.w3.org/1999/02/22-rdf-syntax-ns#>
PREFIX rdfs: <http://www.w3.org/2000/01/rdf-schema#>
select ?l ?t where {
?l rdfs:label "Argentina"#pt .
?l rdf:type ?t .
}
But it is not recovering anything, just print the variable names. The virtuoso answer.
Actually I do not need to recover the label (?l) too.
Anyone can fix it, or help me to define the correct query?
http in graph name
I'm not sure how you generated your query string, but when I copy and paste your query into the endpoint and run it, I get results, and the resulting URL looks like:
http://pt.dbpedia.org/sparql?default-graph-uri=http%3A%2F%2Fpt.dbpedia.org&sho...
However, the link in your question is:
http://pt.dbpedia.org/sparql?default-graph-uri=pt.dbpedia.org%2F&should-sponge...
If you look carefully, you'll see that the default-graph-uri parameters are different:
yours: pt.dbpedia.org%2F
mine: http%3A%2F%2Fpt.dbpedia.org
I'm not sure how you got a URL like the one you did, but it's not right; the default-graph-uri needs to be http://pt.dbpedia.org, not pt.dbpedia.org/.
The query is fine
When I run the query you've provided at the endpoint you've linked to, I get the results that I'd expect. It's worth noting that the label here is the literal "Argentina"#pt, and that what you've called ?l is the individual, not the label. The individual ?l has the label "Argentina"#pt.
We can simplify your query a bit, using ?i instead of ?l (to suggest individual):
select ?i ?type where {
?i rdfs:label "Argentina"#pt ;
a ?type .
}
When I run this at the Portuguese endpoint, I get these results:
If you don't want the individual in the results, you don't have to select it:
select ?type where {
?i rdfs:label "Argentina"#pt ;
a ?type .
}
or even:
select ?type where {
[ rdfs:label "Argentina"#pt ; a ?type ]
}
If you know the identifier of the resource, and don't need to retrieve it by using its label, you can even just do:
select ?type where {
dbpedia-pt:Argentina a ?type
}
type
==========================================
http://www.w3.org/2002/07/owl#Thing
http://www.opengis.net/gml/_Feature
http://dbpedia.org/ontology/Place
http://dbpedia.org/ontology/PopulatedPlace
http://dbpedia.org/ontology/Country
http://schema.org/Place
http://schema.org/Country

Get nationality of person using DBPedia and SPARQL

I have the following SPARQL query:
SELECT ?nationalityLabel WHERE {
dbpedia:Henrik_Ibsen dbpedia-owl:nationality ?nationality .
?nationality rdfs:label ?nationalityLabel .
}
I have checked that Henrik Ibsen exists and that he has the nationality ontology/property on him:
http://dbpedia.org/page/Henrik_Ibsen
And this is an ontology:
http://dbpedia.org/ontology/nationality
A very similar query to this listed here works:
https://stackoverflow.com/a/10248653/1680130
The problem I have is that the query doesn't return any result.
If I could get help solving this it would be great.
Summarized solution:
Both answers were great so upvote to both but landed on Joshua's in the end because informing about dbpedia-owl being cleaner. Optimal solution in my opinion:
First check with dbpedia-owl for birth-place:
select ?label {
dbpedia:Henrik_Ibsen
dbpedia-owl:birthPlace
[ a dbpedia-owl:Country ;
rdfs:label ?label ]
filter langMatches(lang(?label),"en")
}
If found then get the demonym:
select ?label {
dbpedia:Norway dbpedia-owl:demonym ?label
filter langMatches(lang(?label),"en")
}
If above fails then do the "dirty" query:
SELECT
?nationality
WHERE {
dbpedia:Henrik_Ibsen dbpprop:nationality ?nationality .
filter langMatches(lang(?nationality),"en")
}
Of course is "dirty" means data being correct but not so often present the order might be better other way around because people can be born in a country but from a different.
Kristian's answer is right that the property is dbpprop:nationality that Henrik Ibsen has. You're right that there is a dbpedia-owl:nationality property, too, but Henrik Ibsen doesn't have a value for it, unfortunately. The value of dbpprop:nationality that Henrik Ibsen has, though, is a string, which is a literal, and literals cannot be the subjects of triples in RDF, so ?nationality rdfs:label ?nationalityLabel in your query will never match.
The DBpedia ontology data (dbpedia-owl) tends to be cleaner than the dbpprop data, so you might prefer a solution using dbpedia-owl properties that Henrik Ibsen does have. In this case, you might look to the dbpedia-owl:birthPlace. Then you could get the name the country of the birth places:
select ?label {
dbpedia:Henrik_Ibsen
dbpedia-owl:birthPlace
[ a dbpedia-owl:Country ;
rdfs:label ?label ]
}
SPARQL results
You might want to narrow the permissible languages:
select ?label {
dbpedia:Henrik_Ibsen
dbpedia-owl:birthPlace
[ a dbpedia-owl:Country ;
rdfs:label ?label ]
filter langMatches(lang(?label),"en")
}
SPARQL results
Those queries will produce the name of the country, but it wanted the corresponding demonym, you can get the dbpedia-owl:demonym value of the country, if it's available. It's probably best to make the demonym optional, since a cursory investigation suggests that lots of countries in DBpedia don't have a value for it, so the name of the country may be the only option. E.g.,
select ?name ?demonym {
dbpedia:Henrik_Ibsen dbpedia-owl:birthPlace ?country .
?country a dbpedia-owl:Country ; rdfs:label ?name .
optional { ?country dbpedia-owl:demonym ?demonym }
filter langMatches(lang(?name),"en")
filter langMatches(lang(?demonym),"en")
}
SPARQL results
Two things are wrong with the query:
It's dbpprop:nationality
The label doesn't appear to exist, and unless you make that variable optional, it will eliminate the row altogether. EDIT: *Joshua Taylor's answer reminded me that the label doesn't exist because the dbprop:nationality value is a literal, which cannot be used as a subject resource, therefore, there will never be a label for dbpprop:nationality. Instead, where the data exists, you would use dbpedia-owl:nationality, which you did originally. it just so happens that Henrik_Ibsen has no dbpedia-owl:nationality value associated with him*
Updated query (updated).
SELECT
#### ?label #### See Edit
?nationality
WHERE {
dbpedia:Henrik_Ibsen dbpprop:nationality ?nationality .
#### OPTIONAL { ?nationality rdfs:label ?label . } #### See Edit.
}

dbpedia SPARQL query for finding artist properties

I'm trying to get details about an artist via DBPedia and the SPARQL query language, however, it seems almost impossible (with my understanding) of how to get certain pieces of information.
I'm trying to get an Artist and pull information such as their Hometown. I'm guessing the query should be something similar to that of:
SELECT ?c WHERE {
?b <http://dbpedia.org/property/Artist> <http://dbpedia.org/resource/Arctic_Monkeys>.
?b <http://www.w3.org/2002/07/owl#ObjectProperty> <http://dbpedia.org/ontology/hometown>.
?b rdfs:label ?c.
}
If anyone could enlighten me to how it should be done, that would be amazing.
I've been trying out the queries at:
http://dbpedia.org/sparql
If you want to find the label of their hometown, try this:
SELECT ?hometownLabel WHERE {
<http://dbpedia.org/resource/Arctic_Monkeys> <http://dbpedia.org/ontology/hometown> ?hometown .
?hometown <http://www.w3.org/2000/01/rdf-schema#label> ?hometownLabel .
}
Maybe you don't have a good understanding of SPARQL syntax. Unlike SQL, SPARQL search results by writing some triples with unknow variables in the WHERE clause.
you can try:
prefix dbpedia-owl:<http://dbpedia.org/ontology/>
SELECT ?c
WHERE {
<http://dbpedia.org/resource/Arctic_Monkeys> dbpedia-owl:hometown ?c.
}
With this search, you will get Arctic_Monkeys' hometown.
SELECT ?hometown
WHERE {
dbr:Arctic_Monkeys dbo:hometown ?label.
?label rdfs:label ?hometown.
FILTER(langMatches(lang(?hometown), "en"))
}