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Questions tagged [linked-data]

Linked Data refers to a set of best practices for publishing data on the Web under the Semantic Web standards (RDF, SPARQL, etc.). Please consider asking your question on https://opendata.stackexchange.com, if your question is not closely related to programming or is related to a particular Linked Data dataset.

T. Berners-Lee outlines four principles of linked data in his "Linked Data" note:

  1. Use URIs as names for things
  2. Use HTTP URIs so that people can look up those names
  3. When someone looks up a URI, provide useful information, using the standards (RDF*, SPARQL)
  4. Include links to other URIs, so that they can discover more things
371 questions
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Classes and subclasses in OWL for SPARQL queries with inference

I have a question with OWL and SPARQL that I can't resolve. I have defined several classes, but for the question in question only 3 are the important ones: People, Men and Women; and its definitions would be the following: <#People> a owl:Class ; …
germaaan
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Filter 1 to n relation between subject and objects in RDF graph

I want somehow in python in RDF graph with RDFlib, to filter only the predicates that make 1:n relation between subjects and objects. Could anyone help me with this?
Saeid Hedayati
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SPARQL - select from skos:category - Virtuoso 37000

I have problem with SPARQL. I want to select something from category. For example subjects. I make query like this in http://dbpedia.org/snorql. SELECT ?category ?subject WHERE { ?category a skos:Concept . ?category skos:Concept:…
Cezary
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SPARQL - Select where non uri - Filtred non uri

I am beginier in SPARQL / Linked Data. I have question about querying DBpedia. I understand how to select data where filtering condition is URI. Now, I need to query about data, when key factor is not a resource. It is string. I want select…
Cezary
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EasyRDF - SPARQL querying DBpedia - "Undefined namespace prefix" error

It's my first question. I am making a simple program to query DBpedia. I use PHP API + EasyRdf RDF Library for PHP. The SPARQL query is correct; it's working fine on http://dbpedia.org/snorql. I can use query for API example; it is also correct. I…
Cezary
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Getting RDF for a resource from DBpedia

If I make an HTTP GET request on DBpedia on a resource say with content-type text/turtle,application/rdf+xml,text/ntriples,application/ld+json, I get the HTML content of the page…
Noor
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DBpedia memory error

I'm running a query on DBpedia and come across the following error: Virtuoso 42000 Error SQ200: The memory pool size 400097280 reached the limit 400000000 bytes, try to increase the MaxMemPoolSize ini setting. I'm running the query as a SERVICE…
kurious
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Fetching a list of books adapted into films from dbpedia

I am trying to fetch a list of American movies adapted from books from dbpedia. This is what I have so far: PREFIX onto: PREFIX dcterms: SELECT * WHERE { ?movie dcterms:subject…
kurious
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RDF schema for electoral data

I'm designing an ontology to represent in RDF electoral results from a voting event (election or referendum). I defined the following classes: election electoralList candidate electoralBody and the following properties: totalVotesCasted with…
CptNemo
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Turn text into a picture when it is a link with reactor

I'm building an linked data application and having some trouble with my code which is as following import React from 'react'; import URIUtil from '../../../utils/URIUtil'; class BasicIndividualView extends React.Component { render() { let val,…
Joeri
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Relates OWL individual with OWL axiom

I have to related the owl:axiom with the owl:individual. My RDF is as follows:
skid
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How do I separate @types into different cards using JSON-LD?

The Structured Data Testing Tool doesn't separate my @types into different sections, and places all of the @types into one main type: Product. How can i separate the types so that each are validated as their own container?…
Will
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Access LinkedMDB offline

I need to carry out an experiment that takes into consideration all movies of LinkedMDB including their predicates. LinkedMDB SPARQL endpoint is not very efficient, it gets overloaded easily and refuse connection after sending about 40 consecutive…
M20
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rdflib-jsonld removes a / from URLs while parsing graph

This is my code to populate and parse an rdflib graph: context = { "@context": { "isGiven": URIRef('<'+'https://w3id.org/ontology#isGiven'+rdfLizerItem['ProductByCategory']+'>'), "givenAs":…
kurious
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How do triple stores use linked data?

Lets say I have the following scenario: I have some different ontology files hosted somewhere on the web on different domains like _http://foo1.com/ontolgy1.owl#, _http://foo2.com/ontology2.owl# etc. I also have a triple store in which I want to…
whitefang1993
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