I'm quite new to sparql.
I founded this query to get all country in the UN
select distinct ?s
where { ?s a <http://dbpedia.org/class/yago/WikicatMemberStatesOfTheUnitedNations> }
So I tried to adapt it to Geonames with:
select distinct ?s
where { ?s a <http://dbpedia.org/page/GeoNames> }
But it doesn't work. How can I get every place's name in geonames?
I hope someone can help me with that!
Every publisher uses its own namespace and method to generate URIs of the published entities. The nice thing about Linked Open Data is that it allows such independence while URIs can still be linked using agreed open standards. When different URI represent the same thing, this is declared by linking them with owl:sameAs.
Your query attempt assumes that DPpedia and Geonames use the same URIs, if I understood correctly the intention (I'm not sure qhat you mean by "to adapt"). What you need to do is use two separate variables, and then specify that from the owl:sameAs mappings, you want only those from Geonames.
select distinct *
where { ?cuntryDBpedia a <http://dbpedia.org/class/yago/WikicatMemberStatesOfTheUnitedNations> ;
owl:sameAs ?countryGeonames .
FILTER REGEX (?countryGeonames,"geonames.org")
}
Related
Looking for SPARQL query to do the following:
For example, I have the word Apple. Apple may refer to the organization Apple_Inc or the Species of Plants class as per the ontology. Owl: Thing has a subclass called Species, so I want to return those most relevant/maximum-hit URIs where the keyword Apple does not belong to the Species subclass. So when you return all the URIs, http://dbpedia.org/page/Apple should not be one of them, neither must ANY relevant link that comes under Species subclass.
By maximum-hit/most relevant I mean the top returned results that match the query! Like when you access the PrefixSearch (i.e. Autocomplete) API, it has the parameter called MaxHits.
For example http://lookup.dbpedia.org/api/search/PrefixSearch?QueryClass=&MaxHits=2&QueryString=berl is a link where you want to return the top 2 URIs that match the QueryString=berl.
Like I'm actually really struggling to even explain the work I've done so far because I'm not able to understand the structure and how to formulate a proper query..
with respect to negation in SPARQL, I found a relevant portion of the documentation in the link here.. But I do not know how and where to proceed from there, and cannot understand why keywords like ?person are used.. I can understand the person is used to selected well.. PEOPLE names, but I would like to know how and where to find these keywords like ?person, ?name to represent a specific entity..
SELECT ?uri ?label
WHERE {
?uri rdfs:label ?label .
filter(?label="car"#en)
}
I would really appreciate if someone could link me the part of the documentation I can clearly read and understand that ?uri is used to select a URI in the form www.dbpedia.org'/page/SomeEntity and what these ?person, ?name, ?label represent.
I'm actually so lost.. I will go up and start eating one elephant at a time. For now, I'll be very grateful if I get an answer to this.
If there is anyway you know where I can avoid learning and using SPARQL, that would work too! I know Python well enough, so leveraging an API to pull this information is also fine by me. This question was posted by me.
Answer posted by #Stanislav-Kravin --
SELECT DISTINCT ?s
WHERE
{ ?s a owl:Thing .
?s rdfs:label ?label .
FILTER ( LANGMATCHES ( LANG ( ?label ), 'en' ) )
?label bif:contains '"apple"' .
FILTER NOT EXISTS { ?s rdf:type/rdfs:subClassOf* dbo:Species }
}
I am new to SPARQL and trying to fetch a movie adapted from specific book from dbpedia. This is what I have so far:
PREFIX onto: <http://dbpedia.org/ontology/>
SELECT *
WHERE
{
<http://dbpedia.org/page/2001:_A_Space_Odyssey> a ?type.
?type onto:basedOn ?book .
?book a onto:Book
}
I can't get any results. How can I do that?
When using any web resource, and in your case the property :basedOn, you need to make sure that you have declared the right prefix. If you are querying from the DBpedia SPARQL endpoint, then you can directly use dbo:basedOneven without declaring it, as it is among predefined. Alternatively, if you want to use your own, or if you are using another SPARQL client, make sure that whatever short name you choose for this property, you declare the prefix for http://dbpedia.org/ontology/.
Then, first, to get more result you may not restrict the type of the subject of this triple pattern, as there could be movies that actually not type as such. So, a query like this
select distinct *
{
?movie dbo:basedOn ?book .
?book a dbo:Book .
}
will give you lots of good results but not all. For example, the resource from your example will be missing. You can easily check test the available properties between these two resource with a query like this:
select ?p
{
{<http://dbpedia.org/resource/2001:_A_Space_Odyssey_(film)> ?p <http://dbpedia.org/resource/2001:_A_Space_Odyssey> }
UNION
{ <http://dbpedia.org/resource/2001:_A_Space_Odyssey> ?p <http://dbpedia.org/resource/2001:_A_Space_Odyssey_(film)>}
}
You'll get only one result:
http://www.w3.org/2000/01/rdf-schema#seeAlso
(note that the URI is with 'resource', not with 'page')
Then you may search for any path between the two resource, using the method described here, or find a combination of other patterns that would increase the number of results.
I made a SPARQL query using the official DBpedia endpoint.
I'll take it for example for the main Question:
SELECT ?museum ?EnglishAbstract ?RussianAbstract
WHERE {
?museum dbpedia-owl:abstract ?EnglishAbstract.
?museum a dbpedia-owl:Museum.
filter(lang(?EnglishAbstract)='en')
optional{
?museum dbpedia-owl:abstract ?RussianAbstract.
?museum a dbpedia-owl:Museum.
filter(lang(?RussianAbstract)='ru')
}}
GROUP BY ?museum
With this query (that works good), I find for every row (museum) a bunch of Abstract in 2 languages: English and Russian.
The Russian abstracts are present only if available because I use "OPTIONAL".
Obviously I get a lot of empty attributes.
I would replace the blank attribute with the English abstract (always present).
Reading the W3C SPARQL page, I found that there is a particular testing value that is true when a variable is set: Bound
I would like to write something like this:
If Bound (?RussianAbstract), "?RussianAbstract", "?EnglishAbstract"
--> if RussianAbstract is present, hold it; else, put the EnglishAbstract instead of it.
Does anyone know how can I make it work?
One way to do this is to use COALESCE:
SELECT ?museum (COALESCE(?RussianAbstract, ?EnglishAbstract) as ?Abstract)
Hi I'm trying to learn how to query DBpedia using SPARQL. I can't find any website/source that shows me how do this and I'm finding it difficult to learn how to use all the properties (like the ones available at http://mappings.dbpedia.org/index.php?title=Special%3AAllPages&from=&to=&namespace=202 ). Any good source I can learn from?
So for example if I want to check if the wikipedia page http://en.wikipedia.org/wiki/Inception is a movie (property film) or not, how do I do that?
The wikipedia URL http://en.wikipedia.org/wiki/Inception maps to the dbpedia URI http://dbpedia.org/resource/Inception. Dbpedia has a SPARQL endpoint at: http://dbpedia.org/sparql, which you may use to run queries either programmatically or via the html interface.
To check if http://dbpedia.org/page/Inception is a "movie", you have many options. To give you an idea:
If you know the URI of "movie" in dbpedia (it is http://schema.org/Movie), then run an ASK query to check against that type. ASK will return true/false based on whether the pattern in the where clause is valid against the data:
ASK where {
<http://dbpedia.org/resource/Inception> a <http://schema.org/Movie>
}
If you don't know the URI of "movie" then you have a number of options. For example:
Execute an ASK query with a filter on whether the resource has a type that contains the word "movie" somewhere in its uri (or its associated rdfs:label, or both). You would use a regular expression for this:
ASK where {
<http://dbpedia.org/resource/Inception> a ?type .
FILTER regex(str(?type), "^.*movie", "i")
}
Same idea, but return all matches and post-process the results (programmatically I pressume) to see if they match your request:
select distinct ?type where {
<http://dbpedia.org/resource/Inception> a ?type .
FILTER regex(str(?type), "^.*movie", "i")
}
Return all the types of the resource without applying a filter and post-process to see if they match your request:
select distinct ?type where {
<http://dbpedia.org/resource/Inception> a ?type
}
Many options. The SPARQL spec is you number one resource.
First I suggest you start reading up on what exactly SPARQL is. There are tons of really good tutorials such as: this.
If you want to write SPARQL queries on dbpedia, there are various endpoints that you can use. They don't always accept all features that are supported by SPARQL, but if you don't want to go through the trouble of installing one locally, they can be a relatively reliable test environment. The queries that I am going to write below, have been tested on Virtuoso endpoint.
Let's say you want to find all the movies in dbpedia. You first need to know what is the URI for a movie type in dbpedia. If you open Inception in dbpedia, you can see that the type dbpedia-owl:Film is associated to it. So if you want to get the first 100 movies, you just need to call:
select distinct *
where {
?s ?o dbpedia-owl:Film
} LIMIT 100
If you want o know more about each of these movies, you just need to expand your queries by expanding the triples.
select distinct *
where {
?s ?p dbpedia-owl:Film.
?s ?x ?y.
} LIMIT 100
I have a direct link to a DBPedia page (e.g. Argentina) and I'd like to retrieve some or all links with the owl:sameAs label (e.g. wikidata, freebase, etc.)
All the tutorials that I've read focus on retrieving group of object with particular features (e.g., French films).
I've also read this but it just returns one result instead of the entire list of owl:sameAs.
How do I do this?
The following query returns what you're looking for:
PREFIX dbpedia: <http://dbpedia.org/resource/>
SELECT ?obj WHERE {
dbpedia:Argentina (owl:sameAs|^owl:sameAs) ?obj
}
Note that the URI of the resource is actually http://dbpedia.org/resource/Argentina, not page/Argentina. When you put the first URI into a web browser, though, you get redirected to the latter. Be sure to use the former in your query (or just use the prefix dbpedia:).