2. Linked Data Overview

Tim Berners-Lee's four principles of Linked Data

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.

http://www.w3.org/DesignIssues/LinkedData.html

Five Star Data

http://www.w3.org/DesignIssues/LinkedData.html

Linked Data Triples

This thing's author is Bram Stoker.

<http://example.com/00001> <dc:creator> <http://id.loc.gov/authorities/names/n79061014>

Linked Data Graphs

Simple Graph

More Complex Graph

<?xml version="1.0" encoding="utf-8" ?>

<rdf:RDF

xmlns:rdf="http://www.w3.org/1999/02/22-rdf-syntax-ns#"

xmlns:rdfs="http://www.w3.org/2000/01/rdf-schema#"

xmlns:owl="http://www.w3.org/2002/07/owl#"

xmlns:dcterms="http://purl.org/dc/terms/"

xmlns:dbpedia-owl="http://dbpedia.org/ontology/" >

  <rdf:Description rdf:about="http://dbpedia.org/resource/Nosferatu">

    <dbpedia-owl:basedOn rdf:resource="http://dbpedia.org/resource/Dracula" />

  </rdf:Description>

  <rdf:Description rdf:about="http://dbpedia.org/resource/Count_Dracula">

    <dbpedia-owl:series rdf:resource="http://dbpedia.org/resource/Dracula" />

    <dbpprop:series rdf:resource="http://dbpedia.org/resource/Dracula" />

  </rdf:Description>

  <rdf:Description rdf:about="http://dbpedia.org/resource/Abraham_Van_Helsing">

<dbpedia-owl:series rdf:resource="http://dbpedia.org/resource/Dracula" />

    <dbpprop:series rdf:resource="http://dbpedia.org/resource/Dracula" />

  </rdf:Description>

</rdf:RDF>

http://dbpedia.org/data/Dracula.rdf

{ "@graph": [

    { "@id": "http://dbpedia.org/resource/Dracula_(1931_film)",

      "http://dbpedia.org/ontology/basedOn" : [ "http://dbpedia.org/resource/Dracula" ] } ,

    { "@id": "http://dbpedia.org/resource/Nosferatu",

      "http://dbpedia.org/ontology/basedOn" : [ "http://dbpedia.org/resource/Dracula" ] } ,

    { "@id": "http://dbpedia.org/resource/Count_Dracula",

      "http://dbpedia.org/ontology/series" : [ "http://dbpedia.org/resource/Dracula" ] ,

      "http://dbpedia.org/property/series" : [ "http://dbpedia.org/resource/Dracula" ] } ,

    { "@id": "http://dbpedia.org/resource/Abraham_Van_Helsing",

      "http://dbpedia.org/ontology/series" : [ "http://dbpedia.org/resource/Dracula" ] ,

      "http://dbpedia.org/property/series" : [ "http://dbpedia.org/resource/Dracula" ] } ,

] }

http://dbpedia.org/data/Dracula.json

dbpedia:Dracula dbpprop:author dbpedia:Bram_Stoker .

dbpedia:Dracula dcterms:subject category:Irish_novels ,

category:Hungary_in_fiction ,

category:Gothic_novels ,

category:Transylvania_in_fiction .

dbpedia:Dracula rdf:type ns15:CreativeWork

dbpedia:Nosferatu dbpedia-owl:basedOn dbpedia:Dracula .

http://dbpedia.org/data/Dracula.n3

SELECT *

WHERE {$s $p $o}

PREFIX skos: <http://www.w3.org/2004/02/skos/core#>

SELECT *

WHERE {$s skos:prefLabel $o .

FILTER (REGEX(STR(?o), "utah", "i"))}

Linking Open Data cloud diagram, by Richard Cyganiak and Anja Jentzsch. http://lod-cloud.net/