I am a new one on semantic web. I would like to get all object/values for Microsoft from DBPedia using SPARQL query and save result in RDF format. I have made a query on http://dbpedia.org/sparql which works well and returns all pair/values regarding Microsoft.The code is as follows:
PREFIX rdfs: <http://www.w3.org/2000/01/rdf-schema#>
PREFIX foaf: <http://xmlns.com/foaf/0.1/>
select * where
{{ <http://dbpedia.org/resource/Microsoft> ?property ?value }
UNION
{?property ?value <http://dbpedia.org/resource/Microsoft>}}
What I want is to create RDF format for the results. I read tutorial on https://www.w3.org/TR/rdf-sparql-query/#construct and understood it can be done by using CONSTRUCT query. I changed SELECT to CONSTRUCT, but that did not work. If possible could you tell me what is my mistake and how can I apply CONSTRUCT to my query to get RDF model from the query please? Thanks in advance!
In order to get more clear distinction of the actual triples you retrieve, I'd suggest changing the variables in the following way:
PREFIX rdfs: <http://www.w3.org/2000/01/rdf-schema#>
PREFIX foaf: <http://xmlns.com/foaf/0.1/>
select * where
{{ <http://dbpedia.org/resource/Microsoft> ?property ?value }
UNION
{?subject ?property <http://dbpedia.org/resource/Microsoft>}}
And regarding the result format, just choose "Turtle" or "RDF/XML", instead of "HTML" from the results menu of the SPARQL interface.
Related
I am trying to list all properties created in on a wikibase I installed, using docker-compose, based on this install.
Now, want to list all properties that are available in this wikibase, similar to getting that list available through:
<wikibase.url>wiki/Special:ListProperties
I have also extracted that list through SPARQL with the following SPARQL query:
PREFIX rdf: <http://www.w3.org/1999/02/22-rdf-syntax-ns#>
PREFIX rdfs: <http://www.w3.org/2000/01/rdf-schema#>
PREFIX xsd: <http://www.w3.org/2001/XMLSchema#>
PREFIX wikibase: <http://wikiba.se/ontology#>
PREFIX schema: <http://schema.org/>
PREFIX skos: <http://www.w3.org/2004/02/skos/core#>
SELECT DISTINCT
?property
?propertyType
?propertyLabel
?propertyAltLabel
WHERE {
?property a wikibase:Property ;
rdfs:label ?propertyLabel ;
wikibase:propertyType ?propertyType .
OPTIONAL {?property skos:altLabel ?propertyAltLabel .}
}
Running that SPARQL query is expensive though and I need to run that query often, so I would very much like to get that list of properties to the core wikibase API.
Is that possible?
If you know the namespace number for properties on the target wiki (it’s usually 122 if the wiki has an Item: namespace, or 120 if, like on Wikidata, items are in the main namespace), you can use the core allpages API: https://www.wikidata.org/w/api.php?action=query&list=allpages&apnamespace=120
To also get the labels at the same time, use it as a generator and combine it with the entityterms API (new in 1.35; looks like it’s not documented yet, but see T257658): https://www.wikidata.org/w/api.php?action=query&generator=allpages&gapnamespace=120&prop=entityterms&wbetterms=label
I am trying to show the list of Charities from this page - http://dbpedia.org/page/Category:Charitable_organizations
The list is in is dct:subject of property, I have made a query but it doesn't work.
QUERY
WHERE {
?s dbo:type dbr:Charitable_organization .
}
I do kind of know how to use SPARQL with DBPEDIA but am unsure how to use the dct:subject part and display the `dbr:'
Using the site- http://dbpedia.org/sparql to execute queries. So any help on how I can show the list of charities from that website? Thanks for reading.
Your query should be:
PREFIX rdfs: <http://www.w3.org/2000/01/rdf-schema#>
PREFIX type: <http://dbpedia.org/class/yago/>
PREFIX prop: <http://dbpedia.org/property/>
PREFIX dbr: <http://dbpedia.org/resource/>
## Added ##
PREFIX dbo: <http://dbpedia.org/ontology/>
SELECT *
WHERE {
?s dbo:type dbr:Charitable_organization .
}
Links
Live Results Page Link.
Live Query Definition Link.
I have this query
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 dbpedia: <http://dbpedia.org/>
PREFIX dbpedia_property: <http://dbpedia.org/property/>
PREFIX dbpedia_ontology: <http://dbpedia.org/ontology/>
PREFIX yago: <http://dbpedia.org/class/yago/>
PREFIX schema: <http://schema.org/>
SELECT * WHERE
{
{
SELECT ?school
WHERE
{
?school rdf:type yago:EducationalInstitution108276342 .
FILTER ( contains(str(?school), "Australia") )
}
ORDER BY ?school
}
}
Don't mind the extra brackets as this is part of a larger query.
What I want to know is why thi http://dbpedia.org/page/Academic_structure_of_the_Australian_National_University is included in the results since I specify rdf:type yago:EducationalInstitution108276342. This property is not included in the resource page. I'm using this endpoint: http://dbpedia.org/sparql
Looks like a bug in the Pubby Web interface or in the query that is used to get the data that will be shown.
The query
SELECT * WHERE{
<http://dbpedia.org/resource/Academic_Structure_of_the_Australian_National_University> ?p ?o
}
returns the necessary rdf:type statement.
The other strange thing is that even a SPARQL DESCRIBE query does not return the rdd:type triples:
DESCRIBE <http://dbpedia.org/resource/Academic_Structure_of_the_Australian_National_University>
Although DESCIBE is not really defined in the specs, a user would expect those triples for sure. And maybe this kind of query is used to retrieve the data for the Web pages of resources.
Why does this SPARQL query return no data?
PREFIX dbpedia-owl: <http://dbpedia.org/ontology/>
PREFIX dbpedia: <http://dbpedia.org/resource/>
SELECT *
WHERE {
<http://dbpedia.org/resource/Louis,_Prince_of_Condé_(1530–1569)> dbpedia-owl:abstract ?abstract
}
LIMIT 1
If you look at the DBpedia page, it shows the person has an abstract. Is it to do with the brackets in the URL? If so, how can I get round this?
This URI does not lead to the same result as the DBpedia page - for what ever reason. You can see this with
PREFIX dbpedia-owl: <http://dbpedia.org/ontology/>
PREFIX dbpedia: <http://dbpedia.org/resource/>
SELECT *
WHERE {
<http://dbpedia.org/resource/Louis,_Prince_of_Condé_(1530–1569)> ?p ?o
}
LIMIT 100
But it has an owl:sameAs relation to
http://dbpedia.org/resource/Louis,_Prince_of_Cond%C3%A9_(1530%E2%80%931569)
That means if you use this URI in your query, it should work as expected. But you should indeed apply a FILTER on the language, e.g. 'en' for English abstracts.
As AKSW mentions, the resource actually doesn't have many properties, but is connected to the "canonical" version by an owl:sameAs link. You can keep using the IRI that you're using now, follow owl:sameAs in either direction to any of its equal resources (let's call them ?s), and then ask for the abstract of ?s. (And then it's not a bad idea to filter by language, if that's applicable.) You can do this with a query like this (note that the current DBpedia endpoint uses dbo:, now, not the older dbpedia-owl:):
select ?abstract where {
<http://dbpedia.org/resource/Louis,_Prince_of_Condé_(1530–1569)> (owl:sameAs|^owl:sameAs)* ?s .
?s dbo:abstract ?abstract .
filter langMatches(lang(?abstract),'en')
}
It does not have dbpedia-owl:abstract predicate. If you list its predicates you find the following properties:
http://www.w3.org/2002/07/owl#sameAs
http://xmlns.com/foaf/0.1/name
http://purl.org/dc/elements/1.1/description
http://dbpedia.org/ontology/alias
http://dbpedia.org/ontology/birthYear
http://dbpedia.org/ontology/deathYear
http://dbpedia.org/ontology/viafId
http://dbpedia.org/ontology/deathPlace
http://dbpedia.org/ontology/deathDate
http://dbpedia.org/ontology/birthPlace
http://dbpedia.org/ontology/birthDate
I'm new at semantic web, where I learn basics, but I'm stuck at the beginning.
After reading this link: http://www.cambridgesemantics.com/semantic-university/sparql-by-example, I try some examples by myself, but without success.
For example, using OpenLink Virtuoso SPARQL Query Editor http://demo.openlinksw.com/sparql, I put at Default Graph URI this http://njh.me/foaf.rdf and simple query
PREFIX foaf: <http://xmlns.com/foaf/0.1/>
select ?name
where
{
?person foaf:name ?name .
}
to get name of a person who is owner of this RDF file. Also, if I put following query
PREFIX foaf: <http://xmlns.com/foaf/0.1/>
select ?name
where
{
?OnlineAcount foaf:name ?name .
}
nothing is happening.
Where I make mistake?
The same situation is with https://ai.wu.ac.at/~polleres/foaf.rdf, http://richard.cyganiak.de/foaf.rdf for the first query.
Any help at the beginning of my semantic tour will be appreciated :)
Thanks in advance.
Below the query input pane, there's an option for Sponging. You need to select the option Retrieve remote RDF data for all missing source graphs. Then you'll get results. However, the file that you mentioned actually has lots of foaf:name triples, not just one for the creator of the file. You might try select ?person ?name to see what else is in that data.