dbpedia | 易学教程

Get all properties for a DBpedia class

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How to get a list of properties for a specific class? Consider the class dbpedia-owl:Person . All instances of the Person class have some properties prefixed with dbpprop: . How can I get all the dbpprop: properties that we may find for all the instance of the Person class? The one that works is: select distinct ?property where { ?property <http://www.w3.org/2000/01/rdf-schema#domain> <http://dbpedia.org/ontology/Person> . } In this query you are asking for all the properties that have dbpedia:Person as rdfs:domain . This query requires a schema definition to work and sometime datasets don't

How to use DBPedia to extract Tags/Keywords from content?

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问题 I am exploring how I can use Wikipedia's taxonomy information to extract Tags/Keywords from my content. I found articles about DBPedia. DBpedia is a community effort to extract structured information from Wikipedia and to make this information available on the Web. Has anyone used their web services? Do you know how they work and how reliable it is? 回答1: DBpedia is a fantastic, high quality resource. In order to turn your content into a set of relevant DBpedia concepts, however, you will need

How can I query a country's property like language from DBpedia?

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问题 How can I query a country profile with DBPedia like http://dbpedia.org/page/France and get a property like language? 回答1: Let's start from the beginning, as you don't say what you have tried. DBpedia is a database of information about so-called resources : facts derived from Wikipedia articles stored as RDF triples. Resources are identified by URIs; DBpedia uses the form http://dbpedia.org/resource/* where * is the same as * in http://en.wikipedia.org/wiki/* . So DBpedia has facts about the

Extract all types and their labels in English from DBPedia

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问题 I'm trying to get all types from DBpedia using this SPARQL query: select ?type { ?type a owl:Class . } Now, I want to also include the English label of each type returned by the query. What do I need to add to my query? 回答1: This is a good opportunity to learn a bit more about how to retrieve arbitrary information from DBpedia. Your first query (with a limit added) is: select ?type { ?type a owl:Class . } limit 10 SPARQL results One of the results is http://dbpedia.org/ontology/Animal, which

Nested queries in sparql with limits

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问题 I currently trying to create a sample of the dbpedia data for a use case i have to present. My main goal is to ask for 5 five paintings per european artist (and i want to present only two artists per country at the beginning). The query without the limits is as follows. PREFIX dbpedia-owl:<http://dbpedia.org/ontology/> PREFIX category: <http://dbpedia.org/resource/Category:> PREFIX dcterms:<http://purl.org/dc/terms/> PREFIX prop:<http://dbpedia.org/property/> PREFIX geonames:<http://sws

Why there is differences in the number of links connected to the same property?

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问题 I have noticed that there are a different number of triples using the same property (e.g., isbn ) about a Book, but coming from different sources. For instance, Total http://dbpedia.org/property/isbn links are 20885 while Total http://dbpedia.org/ontology/isbn links are 21132. Why do these numbers differ? I want to know which is suitable for good information gain. 回答1: Although they have similar names, and represent roughly the same information, the properties are not the same. One is “http

To use iSPARQL to compare values using similarity measures

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问题 I have a question for you. I would like to write a query that retrieves the values that are similar (given a function of similarity, such as Lev) to a given string "Londn" to make the comparison with the predicate "RDFS:label" of DBPedia. In Output, for example, I would like to get the value of "London". I have read that a usable approach might be to use iSPARQL ("Imprecise SPARQL") although it is not very widely used in the literature. Can I use iSPARQL or is there some SPARQL approach to

Retrieving a DBpedia resource by its string name with SPARQL

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问题 I am trying to get the resource describing country Romania by the country name with this query: PREFIX foaf: <http://xmlns.com/foaf/0.1/> PREFIX : <http://dbpedia.org/resource/> SELECT DISTINCT ?x WHERE { ?x foaf:name 'Romania' } SPARQL results However, it does not retrieve anything. How can I get the resource http://dbpedia.org/resource/Romania ( :Romania ) by the string 'Romania' . If I want to retrieve the name of the country by the country resource I use the following query which works

Retrieving dbpedia-owl:type value of resource with dbpedia-owl:wikiPageRedirect value?

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Visitng http://dbpedia.org/resource/Cupertino shows the DBpedia RDF information about Cupertino. As you can see, it has, among others, the property and value: dbpedia-owl:type dbpedia:City However, this query on the DBpedia endpoint returns no results: SELECT ?type WHERE { dbpedia:Cupertino dbpedia-owl:type ?type } SPARQL results Why can't I retrieve the value of the dbpedia-owl:type property? You've got an interactive webservice in front of you, and one of the most useful things that you can do is generalize your query into one that should return a superset of the results you're looking for,

How to get all companies from DBPedia?

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I'm new to querying DBPedia. How can I get all companies from http://dbpedia.org/sparql ? This query returns only 50'000 organizations: SELECT DISTINCT * WHERE {?company a dbpedia-owl:Company} You're right that your query isn't returning all the companies. The pattern is correct, though. Notice that this query which only counts the companies returns 88054: prefix dbpedia-owl: <http://dbpedia.org/ontology/> select (count(distinct ?company) as ?count) where { ?company a dbpedia-owl:Company } SPARQL results I think this is a limit imposed by the DBpedia SPARQL endpoint for performance reasons.