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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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Find all classes, without reasoning

When I have Forward Chaining enabled, I would do: "...WHERE { ?class rdf:type rdfs:Class }" now, I want to do it without the reasoner, so I tried: "...WHERE { ?class rdf:type* rdfs:Class }" but this gave me instances of the classes and not all the…
gsamaras
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How to get country of a municipality?

The ontology lies in XML here. I also tried to ask which are the classes of my world and then tried to check if my resource (the municipality) really belongs to that class, but still Country slips away (although it's fetched when I ask for all the…
gsamaras
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Practical usage for linked data

I've been reading about linked data and I think I understand the basics of publishing linked data, but I'm trying to find real world practical (and best practise) usage for linked data. Many books and online tutorials talk a lot about RDF and SPARQL…
user2988129
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How do I query a SPARQL endpoint such as DBPedia with Sesame?

I use Sesame triplestore to store my data. When I try to use the query interface with Sesame with external resources such as dbpedia, I get no results. This query returns results with snorql but not the Sesame after adding all the necessary…
kurious
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Discovering the version of a SPARQL endpoint

Given a SPARQL endpoint (which can be either SPARQL 1.0 or 1.1), say for example http://pt.dbpedia.org/sparql, how do I find which version of SPARQL it supports? [One option is to try out a 1.1 feature such as aggregate functions and see it works…
Nandana
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How to get data from rdf in haskell rdf4h

Im trying to get the capital of the country from rdf using rdf4h Right (rdf::TriplesGraph) <- parseURL (XmlParser Nothing Nothing) "http://live.dbpedia.org/data/Spain.rdf" let c = query rdf (Just (UNode "http://live.dbpedia.org/resource/Spain")) …
Herokiller
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Populating an OWL ontology from external SPARQL endpoints

I would like to link two distinct data-sets using sparql endpoints (let say http://dbpedia.org/sparql and http://pubmed.bio2rdf.org/sparql ) I am going to create an OWL ontology from scratch, and then populate this ontology with these two different…
Bedi Egilmez
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How to build correct SPARQL Query

I need to get all players who have ever played for football team using SPARQL query and dbpedia.org I can get current team members using http://dbpedia.org/sparql and this query: PREFIX geo: PREFIX p:…
Dmitry Kazakov
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Separation between TBox and ABox in Fuseki with TDB and Pubby

For my current project I need to load a dataset and different ontologies and expose everything as linked data using Fuseki with TDB and Pubby. Pubby will take a data set from a single location and create URIs based on that location, therefore if we…
paxRoman
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Pubby displays question marks instead of the actual namespaces

Some URIs that represent namespaces do not appear in Pubby Linked Data Frontend: there is just a question mark (?) sign where the namespace should be even though when you click on that URL it will take you to the right page. I initially assumed that…
paxRoman
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Accessing linked data graphs using SPARQL

I am using OpenLink Virtuoso to convert a Relational Database to RDF using this tutorial. I have a database with 5 tables (Authors, Keywords, Publications, References, Rights), and I imported them in Virtuoso database using .csv files. In the end of…
sokras
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Dynamically convert an RDB to RDF

I am using Virtuoso Open Source Edition. My question is how can I dynamically convert an RDB to RDF? Let's say we have a Relational Database which we need to convert to RDF, but at the same time this Database needs to be updated all the time. Is…
sokras
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exposing a sparql endPoint publicly?

I have a website power by a tomcat server. My application tap on a tripleStore that i would like to make public trough a sparql endpoint at www.mywebsiteaddress/sparql. What configuration do i need on my webserver to do that ? I use Jena Fuseki on…
MaatDeamon
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Advantage of ontology over RDBMS in an offline application

Is there any advantage of using ontology based database (linked data) instead of RDBMS in an offline application? Does linked data provide more relations and reasoning capabilities using SPARQL than SQL? Can I not achieve the same using joins in…
Nithish Inpursuit Ofhappiness
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Parser to extract URIs from RDF/XML web page for my Web-Crawler in Java

I am building a web Crawler for Linked Data. I have differentiated between HTML and RDF/XML page by following code: public static int checktype(URL url) throws IOException { String contentType = ((HttpURLConnection)…
Prannoy Mittal
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