"why should I care about a globally distributed hypertext when the whole encyclopedia sits in a CD?"

"... WikiPedia"

Resource Description Framework

RDF : Linked Data = HTML : Hypertext

S         P         O

Resource Description Framework

RDF : Linked Data = HTML : Hypertext

# subject                    # predicate                                       # object

<http://example.com/grandma> <http://www.w3.org/1999/02/22-rdf-syntax-ns#type> <http://schema.org/Person> .
<http://example.com/grandma> <http://schema.org/relatedTo>                     <http://example.com/me> .
<http://example.com/grandma> <https://schema.org/birthDate>                    "1934" .
<http://cookingsite.net/pie> <http://schema.org/author>                        <http://example.com/grandma> .
<http://cookingsite.net/pie> <http://www.w3.org/1999/02/22-rdf-syntax-ns#type> <http://schema.org/Recipe> .
<http://cookingsite.net/pie> <http://schema.org/recipeIngredient>              <http://foodnoprofit.info/apple> .
<http://example.com/me>      <http://schema.org/owns>                          <http://foodnoprofit.info/apple> .
<http://example.com/me>      <http://www.w3.org/1999/02/22-rdf-syntax-ns#type> <http://schema.org/Person> .

S         P         O

"why should I care about a globally distributed database when all my data can sit in my server/cluster?"

"... Wikidata"
(and the Linked Data Cloud)

Queries

"Give me world recipes containing Black Pepper and Eggs"

PREFIX dbo: <http://dbpedia.org/ontology/>
PREFIX rdfs: <http://www.w3.org/2000/01/rdf-schema#>

SELECT DISTINCT ?s, ?l WHERE {
    ?s a dbo:Food .
    ?s dbo:ingredient <http://dbpedia.org/resource/Black_pepper> .
    ?s dbo:ingredient <http://dbpedia.org/resource/Egg_(food)> .
    ?s rdfs:label ?l .

    FILTER (lang(?l) = "en")
}

Queries

"Give me movies based on books written by science fiction writers"

PREFIX wd: <http://www.wikidata.org/entity/>
PREFIX wdt: <http://www.wikidata.org/prop/direct/>
PREFIX rdfs: <http://www.w3.org/2000/01/rdf-schema#>

SELECT ?p ?w ?m WHERE {
    ?m  wdt:P31    wd:Q11424 .     # ?m is a Movie
    ?m  wdt:P144   ?w .            # ?m is based on ?w
    ?w  wdt:P50    ?p .            # ?w written by ?p
    ?p  wdt:P106   wd:Q18844224 .  # ?p is a science fiction writer
}

Read blog post by InsideOut10

Queries

"List hungarian and russian porn actresses,

with hair color and photo"

PREFIX wd: <http://www.wikidata.org/entity/>
PREFIX wdt: <http://www.wikidata.org/prop/direct/>

SELECT
?x ?xLabel ?nationalityLabel ?haircolorLabel ?img
WHERE {
  ?x wdt:P106 wd:Q488111 .
  ?x wdt:P27 ?nationality .
  ?x wdt:P1884 ?haircolor .
  ?x wdt:P18 ?img .
  
  FILTER( ?nationality IN (wd:Q159, wd:Q28) )
  
  SERVICE wikibase:label { bd:serviceParam wikibase:language "en" }
}

Queries

"Voti alla Camera del 19/10/2017: Disposizioni concernenti la coltivazione e la somministrazione della cannabis a uso medico."

SELECT DISTINCT
?votazione ?descrizione ?numeroVotazione
?nome ?cognome ?espressione ?infoAssenza ?deputato

WHERE {

## Votazioni del 19 Ottobre 2017
?votazione a ocd:votazione;
   dc:date '20171019';
   dc:description ?descrizione;
   dc:identifier ?numeroVotazione.

## voti espressi
?voto a ocd:voto;
   ocd:rif_votazione ?votazione;
   dc:type ?espressione;
   ocd:rif_deputato ?deputato.
OPTIONAL{?voto dc:description ?infoAssenza}

## info deputato
?deputato foaf:surname ?cognome;
   foaf:firstName ?nome.  

}
ORDER BY ?cognome