I am trying to query the WikiData database using their SPARQL endpoint. Here I want to assign specific values to certain variables independent from each other. I know that the VALUES keyword can be used for this, however, is there a way of doing this for multiple variables without having to specify each possible combination? For example, the query looks like this:
SELECT ?relation1 ?item1?
WHERE {wd:Q31 ?relation1 ?item1 .}
I would like to specify the values for both ?relation1 and ?item1 without having to go over each possible combination.
Thank you.
Edited answer:
Yes, you can use multiple VALUES statements.
This can be written like this:
SELECT *
WHERE {
VALUES ?person {wd:Q35332 wd:Q23844} #Brad Pitt and Geroge Clooney
VALUES ?property {wdt:P27 wdt:P19} #Country of nationality and place of birth
?person ?property ?o ;
rdfs:label ?personLabel .
?o rdfs:label ?oLabel .
FILTER(LANG(?personLabel) = 'en' && LANG(?oLabel) = 'en')
}
You will then see these results:
This link will contain more information.
Related
In my company's taxonomy, all concepts have a value for skos:prefLabel, and most have a bunch of values for a custom property -- let's call it ex:keyword -- whose values have the datatype rdf:langString. I want to find concepts where the value of skos:prefLabel does NOT exactly match ANY value of ex:keyword, when case and language are ignored.
It is fairly straightforward to write a query for concepts where the values DO match, like this:
SELECT *
WHERE {
?concept skos:prefLabel ?label ;
ex:keyword ?kw
FILTER (lcase(str(?label)) = lcase(str(?kw)))
}
Where I'm getting tripped up is in trying to negate this.
Using != in the FILTER would just return a bunch of cases where ?label and ?kw don't match, which is not what I'm after.
What I would like is to be able to use a FILTER NOT EXISTS, but that's invalid with an expression like (?a = ?b); it only works with something like {?a ?b ?c}.
I suspect that there is a proper way to express FILTER NOT EXISTS (?a = ?b) in SPARQL, but I don't know what it is. Can someone help?
The trick is to put the triple pattern for matching the keyword in the FILTER NOT EXISTS, like so:
SELECT *
WHERE {
?concept skos:prefLabel ?label .
FILTER NOT EXISTS { ?concept ex:keyword ?kw .
FILTER(lcase(str(?label)) = lcase(str(?kw)))
}
}
This query says "I want all concepts with a preflabel such that the concept has no keyword value that matches that prefLabel".
I am trying to obtain the wikidata entity_id containing a given literal, for example "crypto".
I'm using:
SELECT ?item WHERE {
?o rdfs:label ?ol
FILTER (lang(?ol) = 'en')
FILTER(contains(str(?ol),'crypto' ))
}
Of course, the wrong approach :-/
Any help, more than welcome. Thx in advance.
I want to gather all properties of a item from wikidata.
All queries I see so far assume you know properties you are looking for, but in my case, I'm not.
For example, when querying for Q1798740, I would like a returned value that looks like
[{"item": "Q1798740",
"P31": ["Q1146"],
"P17": ["Q70972"],
...
"P2043":"70 metres"}
]
and that contains all statements from the wikidata page
What query should I perform?
You need only to ask for {wd:Q1798740 ?p ?value} but it would be useful also to get the labels of the properties, which is a bit trickier:
SELECT DISTINCT ?p ?property_label ?value
WHERE
{
wd:Q1798740 ?p ?value .
?property wikibase:directClaim ?p ;
rdfs:label ?property_label .
FILTER(LANG(?property_label)="en")
}
I use AllegroGraph and Sparql 1.1.
I need to do ascending sort on a column and make the Sparql query to return empty values at the last.
Sample data:
<http://mydomain.com/person1> <http://mydomain.com/name> "John"^^<http://www.w3.org/1999/02/22-rdf-syntax-ns#XMLLiteral>
<http://mydomain.com/person1> <http://www.w3.org/1999/02/22-rdf-syntax-ns#type> <http://mydomain.com/person>
<http://mydomain.com/person2> <http://mydomain.com/name> "Abraham"^^<http://www.w3.org/1999/02/22-rdf-syntax-ns#XMLLiteral>
<http://mydomain.com/person2> <http://www.w3.org/1999/02/22-rdf-syntax-ns#type> <http://mydomain.com/person>
<http://mydomain.com/person3> <http://www.w3.org/1999/02/22-rdf-syntax-ns#type> <http://mydomain.com/person>
Here I need the Sparql to return Abraham, followed by John and person3 that does not have a name attribute.
Query I use:
select ?name ?person {
?person <http://www.w3.org/1999/02/22-rdf-syntax-ns#type> <http://mydomain.com/person>.
optional {?person <http://mydomain.com/name> ?name.}
} order by asc(?name )
Current output is person3 (null), followed by Abraham and John.
Please let me know your thoughts.
I don't have AllegroGraph at hand but AFAIK it supports multiple order conditions:
select ?name ?person {
?person <http://www.w3.org/1999/02/22-rdf-syntax-ns#type> <http://mydomain.com/person> .
optional {?person <http://mydomain.com/name> ?name . }
} order by (!bound(?name)) asc(str(?name))
First condition sorts based on whether ?name is bound or not and if this condition does not find a difference, the second condition is used. Note the use of str() to convert rdf:XMLLiteral to a datatype for which comparison is supported.
(You may also want to add . at the end of each row in your ntriples data.)
I am using SPARQL query on DBpedia into a Prolog project and I have a doubt. I would know if a word is, most probably, a NAME OF A PERSON (something like: John, Mario) or a PLACE (like a city: Rome, London, New York).
I have implement the following two queries, the first gives me the number of persons having a specific name, and the second gives me the number of places having a specific name.
1) Query for a PERSON NAME:
select COUNT(?person) where {
?person a dbpedia-owl:Person .
{ ?person foaf:givenName "John"#en }
UNION
{ ?person foaf:surname "John"#en }
}
For the name John, I obtain the following output: callret-0: 7313, so I think that it has found 7313 instances for the proper name John. Is it right?
2) Query for a PLACE NAME:
select COUNT(?place) where {
?place a dbpedia-owl:Place .
{ ?x rdfs:label "John"#en }
}
The problem is that, as you can see in the previous “place” query, I have inserted John as parameter, which is not a place name but a proper name of persons, but I obtain the following strange result: callret-0: 81900104
The problem is that, in this way, if I compare the output of the previous two queries, it seems that John is a place and not a person name! This is not good for my scope; I have tried with other personal names and it always happens that the place query gives me a bigger output than the name query.
Why? What am I missing? Are there some errors in my queries? How can I solve it to have a correct result?
Actually, when I run the query you provided:
select COUNT(?place) where {
?place a dbpedia-owl:Place .
{ ?x rdfs:label "John"#en }
}
I get the result 93027312, not 81900104, but that does not really matter much. The strange results arise because ?x and ?place don't have to be bound to the same thing, so you are getting all the dbpedia-owl:Places and counting them, but the number of result rows is the number of dbpedia-owl:Place multiplied by the number of things with rdfs:label "John#en":
select COUNT(?place) where { ?place a dbpedia-owl:Place }
=> 646023
select COUNT(?x) where { ?x rdfs:label "John"#en }
=> 144
646023 × 144 = 93027312
If you actually ask for dbpedia-owl:Places that have the rdfs:label "John#en", you'll get no results:
select COUNT(?place) as ?numPlaces where {
?place a dbpedia-owl:Place ;
rdfs:label "John"#en .
}
SPARQL results
Also, you might consider using dbpprop:name instead of rdfs:label. Some results seem like they are more useful that way. For instance, let us find places called "Springfield". If we ask for places with that name we get no results:
select * where {
?place a dbpedia-owl:Place ;
rdfs:label "Springfield"#en .
}
SPARQL results
However, if we modify the query and use dbpprop:name, we get 17. Some of these are duplicates though, so you might have to do something else to remove duplicates. The point, though, is that dbpprop:name got some results, and rdfs:label didn't.
select * where {
?place a dbpedia-owl:Place ;
dbpprop:name "Springfield"#en .
}
SPARQL results
You can even use dbpprop:name in working with the names of persons, although it's not as useful, because the dbpprop:name value for most persons is their entire name. To find persons with the given name John using dbpprop:name requires a query like:
select * where {
?place a dbpedia-owl:Person ;
dbpprop:name ?name .
FILTER( STRSTARTS( str( ?name ), "John" ) )
}
(or you could use CONTAINS instead of STRSTARTS), but this becomes much more expensive, because it has to select all persons and their names, and then filter through that set. Being able to select persons based on a specific name (e.g., with foaf:givenName) is much more efficient.