SUMMER SCHOOL LEX 2014 - RDF + SPARQL querying the web of (lex)data

RDF + SPARQL
querying the web
of (lex)data
Diego Valerio Camarda
regesta.exe
www.regesta.com
diego.camarda@regesta.com
dvcama @ github&twitter
DiegoValerioCamarda @ slideshare

a (really) short
introduction to
linked open data

what about IRIs and RDF
a new way to publish data on the web
ids are ambiguous and suck!
Use URIs
as names for things
Use HTTP URIs
so that people can look up those names
Use the standards (RDF, SPARQL)
providing useful information
Include links to other URIs
so that they can discover more things
linked data principles
Tim Berners-Lee
July 27, 2006

The Children and Families Act 2014
http://www.legislation.gov.uk/id/uksi/2014/2270
what about IRIs and RDF
turning documents into data
ids are ambiguous and suck!

A new way to design
databases
RDF
(aka ’define knowledge’)

Go Triples, go!
the standard (old) approach
ID_P COGNOME NOME REF_ID_SOCIETA GENERE
1 Camarda Diego 1 maschio
2 … … … …
ID_SOCIETA DENOMINAZIONE SITO
1 Regesta.exe srl www.regesta.com

Go Triples, go!
the new (cool) approach
<http://www.regesta.com/diego>Subject

Go Triples, go!
<http://www.regesta.com/diego>
<http://xmlns.com/foaf/0.1/familyName>
Subject
Predicate

Go Triples, go!
<http://xmlns.com/foaf/0.1/familyName>
‘Camarda’.
Subject
Predicate
Object

Go Triples, go!
<http://xmlns.com/foaf/0.1/familyName> ‘Camarda’.
<http://xmlns.com/foaf/0.1/firstName> ‘Diego’.
<http://xmlns.com/foaf/0.1/gender> ‘male’.

Go Triples, go!
<http://xmlns.com/foaf/0.1/familyName> ‘Camarda’ ;
<http://xmlns.com/foaf/0.1/firstName> ‘Diego’ ;
<http://xmlns.com/foaf/0.1/gender> ‘male’ .

Go Triples, go!
ok, but what a “diego” is?

Go Triples, go!
it’s a person!
<http://www.regesta.com/diego> a <http://xmlns.com/foaf/0.1/Person>

Go Triples, go!
adding a Class
<http://xmlns.com/foaf/0.1/gender> ‘male’ .
<http://www.w3.org/1999/02/22-rdf-syntax-ns#type>
<http://xmlns.com/foaf/0.1/Person> .

Go Triples, go!
building a graph
<http://xmlns.com/foaf/0.1/gender> ‘male’ ;
<http://www.w3.org/1999/...#type> <http://xmlns.com/foaf/0.1/Person> .
<http://www.w3.org/ns/org#memberOf>
<http://www.regesta.com/about> .

Go Triples, go!
building a graph
<http://www.w3.org/1999/...#type> <http://xmlns.com/foaf/0.1/Person> ;
<http://www.w3.org/ns/org#memberOf> <http://www.regesta.com/about> .
<http://www.regesta.com/about>
<http://www.w3.org/1999/02/22-rdf-syntax-ns#type>
<http://www.w3.org/ns/org#Organization> .

Go Triples, go!
building a graph
<http://www.w3.org/1999/...#type> <http://www.w3.org/ns/org#Organization> .

Go Triples, go!
building a graph
<http://www.w3.org/1999/...#type> <http://www.w3.org/ns/org#Organization> ;
<http://www.w3.org/2004/02/skos/core#prefLabel> ‘Regesta.exe srl’ ;
<http://xmlns.com/foaf/0.1/homepage> <http://www.regesta.com> .

Go Triples, go!
Objects could be Subjects
diego

Go Triples, go!
considering diego and regesta
diego
regesta

Go Triples, go!
<diego> <memberOf> <regesta>
diego
regesta

Go Triples, go!
but, <regesta> <locatedIn> <rome>
diego
regesta
rome

Go Triples, go!
<diego> <placeOfBirth> <rome>
diego
regesta
rome

Go Triples, go!
<rome> <parentADM> <italy>
diego
regesta
rome
italy

Go Triples, go!
<silvia> <placeOfBirth> <italy>
diego
regesta
silvia
rome
italy

Go Triples, go!
<silvia> <…> <…>
diego
regesta
silvia
rome
italy

Go Triples, go!
<…> <…> <…> = a knowledge graph!
diego
regesta
silvia
rome
italy

A lot of sentence
to achieve (descriptive) freedom
<http://www.regesta.com/diego> <http://xmlns.com/foaf/0.1/familyName> ‘Camarda’ .
<http://www.regesta.com/diego> <http://xmlns.com/foaf/0.1/firstName> ‘Diego’ .
<http://www.regesta.com/diego> <http://xmlns.com/foaf/0.1/gender> ‘male’ .
<http://www.regesta.com/diego> <http://www.w3.org/1999/02/22-rdf-syntax-ns#type> <http://xmlns.com/foaf/0.1/Person> .
<http://www.regesta.com/diego> <http://www.w3.org/ns/org#memberOf> <http://www.regesta.com> .
<http://www.regesta.com/silvia> <http://xmlns.com/foaf/0.1/familyName> ‘Mazzini’ .
<http://www.regesta.com/silvia> <http://xmlns.com/foaf/0.1/firstName> ‘Silvia’ .
<http://www.regesta.com/silvia> <http://xmlns.com/foaf/0.1/gender> ‘female’ .
<http://www.regesta.com/silvia> <http://www.w3.org/1999/02/22-rdf-syntax-ns#type> <http://xmlns.com/foaf/0.1/Person> .
<http://www.regesta.com/silvia> <http://www.w3.org/ns/org#memberOf> <http://www.regesta.com> .
<http://www.regesta.com> <http://www.w3.org/1999/02/22-rdf-syntax-ns#type> <http://www.w3.org/ns/org#Organization> .
<http://www.regesta.com> <http://www.w3.org/2004/02/skos/core#prefLabel> ‘Regesta.exe srl’ .
<http://www.regesta.com/silvia> <http://xmlns.com/foaf/0.1/knows> <http://www.regesta.com/diego> .
<…> <…> <…>.
<noBeer> <makeGoCreazy> <homer>. <noTv> <makeGoCreazy> <homer>.<noBeer> <makeGoCreazy> <homer>. <noTv>
<makeGoCreazy> <homer>. <noBeer> <makeGoCreazy> <homer>. <noTv> <makeGoCreazy> <homer>. <noBeer>
<makeGoCreazy> <homer>. <noTv> <makeGoCreazy> <homer>. <noBeer> <makeGoCreazy> <homer>. <noTv> <makeGoCreazy>
<homer>. <noBeer> <makeGoCreazy> <homer>. <noTv> <makeGoCreazy> <homer>. <noBeer> <makeGoCreazy> <homer>.
<noTv> <makeGoCreazy> <homer>. <noBeer> <makeGoCreazy> <homer>. <noTv> <makeGoCreazy> <homer>. <noBeer>
<noTv> <makeGoCreazy> <homer>. <noBeer> <makeGoCreazy> <homer>. <noTv> <makeGoCreazy> <homer>. <noBeer>
<noTv> <makeGoCreazy> <homer>. <noBeer> <makeGoCreazy> <homer>. <noTv> <makeGoCreazy> <homer>. <noBeer> …

RDF
http://www.w3.org/standards/techs/rdf
SPARQL
http://www.w3.org/standards/techs/sparql
ONTOLOGIES
http://www.w3.org/standards/semanticweb/ontology
Did you studied HTML? Good!
it's time for a new standard

The Resource Description Framework
is a general-purpose language for representing
information in the Web.
It's time for a new standard
RDF

The SPARQL Protocol and RDF Query Language
is a query language and protocol for RDF.
SPARQL

On the Semantic Web, vocabularies define
the concepts and relationships
(also referred to as “terms”)
used to describe and represent
an area of concern.
Ontologies

PREFIX foaf: <http://xmlns.com/foaf/0.1/>
PREFIX dc: <http://purl.org/dc/elements/1.1/>
PREFIX rdfs: <http://www.w3.org/2000/01/rdf-schema#>
foaf:firstName
dc:title
rdfs:label
Pre:fixes (ontologies)
just a few words

Resource Description
Framework
› SPARQL endpoint
› dereferenceable URIs
› content negotiation
› standard ports, like 80 (HTTP)
› JSONP support
MUST!

Resource Description
Framework
› SPARQL endpoint
› dereferenceable URIs
› content negotiation
› standards port, like 80 (HTTP)
› JSONP support
› up-to-date
› the endpoint URL is easy to deduce from resources
› the resources are described by dc:title or rdfs:label
› the endpoint hosts a page for humans
› the resources and the endpoint are on the same domain
SHOULD!
(please do it, for me)

SELECT * {?minnesota ?banana ?sun}
SPARQL
a must know query language

SPARQL
group graph pattern
diego
regesta
silvia
rome
italy
diego
regesta
silvia
rome
italy

SPARQL
group graph pattern
diego
regesta
rome
silvia
italy
silvia
italy

SELECT ?person {
?person <placeOfBirth> ?place.
?person <memberOf> ?company .
?company <locatedIn> ?place .
}
SPARQL
group graph pattern
<diego>

SELECT ?person ?prop ?obj {
?person <placeOfBirth> ?place.
?person <memberOf> ?company.
?person ?prop ?obj .
?company <locatedIn> ?place .
}
SPARQL
group graph pattern
(turn the page)

person prop obj
<diego> rdf:type foaf:Person
<diego> foaf:firstName ‘Diego’
<diego> foaf:familyName ‘Camarda’
<diego> foaf:gender ‘male’
<diego> org:memberOf <regesta>
SPARQL
group graph pattern

DESCRIBE <diego>
SPARQL
describe
(turn the page)

<diego> rdf:type foaf:Person .
<diego> foaf:firstName ‘Diego’ .
<diego> foaf:familyName ‘Camarda’ .
<diego> foaf:gender ‘male’ .
<diego> org:memberOf <regesta> .
<silvia> foaf:knows <diego> .
SPARQL
describe

DISTINCT, COUNT
GRAPH, PREFIX
isBlank, isIRI, isLiteral, isNumeric
FILTER, REGEX, STR
FILTER NOT EXISTS, MINUS
ORDER BY, OFFSET, LIMIT
for other stuff
http://www.w3.org/TR/sparql11-query/
SPARQL
minimum requirements

Please start negotiating content
right now!
Hi dude, I accept:
text/html,application/xhtml+xml
Html
pageGreat! I’ll serve you a web page
Hi dude, I accept:
application/rdf+xml
RDF
dataGreat… 302, redirect!
Hi dude, I accept:
pizza/margherita
406
errormmm… sorry

right now!
application/rdf+xml
application/xml
text/plain
text/turtle
application/x-turtle
application/trix
application/x-trig
text/n3
text/rdf+n3
application/trix
application/x-trig
application/x-binary-rdf
text/x-nquads
application/ld+json
application/rdf+json
application/xhtml+xml
text/xml
application/json
application/rdf+xml
application/rdf+n3
application/sparql-results+xml
application/sparql-results+json

curl -L -H "Accept: application/rdf+xml"
http://dati.camera.it/ocd/governo.rdf/g102
curl -L -H "Accept: text/n3"
http://dati.camera.it/ocd/governo.rdf/g102
using CURL…

Java : Sesame / Jena
Python : RDFLib
Ruby : RDF.rb
nodeJs : sparql-client
or, as I do,
simple HTTP GET +
parsing results as json or xml
…or a framework!

RDF data
storing and deploying

It’s slow
so keep calm
1 record 15 triples
2.949.771 votes 64.948.856 triples
usually
eg. Chamber of deputies
data big data
RDF probably will transform

Virtuoso
Sesame
Fuseki (Jena)
Owlim / Bigdata (Sesame)
AllegroGraph
D2R server
ARC2
…
Triplestores
I just need a SPARQL endpoint
I just really need http://yourdomain/sparql

select distinct ?o where {?s a ?o}
select ?o count(distinct ?s) where {?s a ?o}
select count(?s) where {?s ?p ?o}
select count(?s) ?class where {?s ?p ?o; a ?class}
select distinct ?p where {?s a <http://classe>; ?p ?o}
select ?p count(?p) where {?s a <http://classe>; ?p ?o}
select ?s where {?s a <http://classe>}
?p ?o where {<http://URI> ?p ?o}
select distinct ?s ?title where {?s a <http://classe>;
dc:title ?title. FILTER(REGEX(? title,’parola’,’i’))} LIMIT 100
SPARQL magic
a query for all seasons

Case studies
Chamber of deputies
Senate of Republic

http://dati.camera.it/sparql
http://dati.senato.it/sparql
Useful links

All Bills filtered by year
SELECT DISTINCT * {?bill a ocd:atto; dc:title ?title; dc:date ?date .
FILTER(regex(?date,'^2014'))} ORDER BY ?date
Last voted Bills
SELECT distinct * WHERE {
?bill a ocd:atto; dc:title ?title.
?votazione a ocd:votazione; ocd:rif_attoCamera ?bill; dc:date ?data; dc:title ?denominazione;
dc:description ?descrizione; ocd:votanti ?votanti; ocd:votazioneFinale 1; ocd:favorevoli
?favorevoli; ocd:contrari ?contrari; ocd:astenuti ?astenuti;
ocd:rif_leg <http://dati.camera.it/ocd/legislatura.rdf/repubblica_17>}
ORDER BY DESC(?data)
Example queries
Chamber of deputies

All Bills filtered by year
PREFIX osr: <http://dati.senato.it/osr/>
SELECT DISTINCT * {?bill a osr:Ddl; osr:titolo ?title; osr:dataPresentazione ?date .
FILTER(regex(STR(?date),'^2014'))} ORDER BY ASC(?date)
Last approved Bills
PREFIX osr: <http://dati.senato.it/osr/>
SELECT DISTINCT ?ddl ?titolo ?titoloBreve ?natura ?stato ?dataApprovato
WHERE { ?ddl a osr:Ddl. ?ddl osr:statoDdl ?stato.
?ddl osr:ramo "S"^^<http://www.w3.org/2001/XMLSchema#string>.
?ddl osr:dataPresentazione ?dataPresentazione. ?ddl osr:titolo ?titolo.
OPTIONAL { ?ddl osr:titoloBreve ?titoloBreve }. ?ddl osr:natura ?natura.
?ddl osr:dataStatoDdl ?dataApprovato. ?ddl osr:testoApprovato ?testoApprovato
FILTER(xsd:date(str(?dataApprovato)) <= xsd:date(str("2014-12-31")))
FILTER(xsd:date(str(?dataApprovato)) >= xsd:date(str("2014-01-01")))
} ORDER BY ?dataApprovato
Example queries
Senate of Republic

http://gov.tso.co.uk/legislation/sparql
http://openuplabs.tso.co.uk/sparql/gov-legislation
http://www.opsi.gov.uk/legislation-api/developer/formats/rdf
Useful links

All ‘Works’ filtered by year
SELECT ?work ?date ?title {?work a frbr:Work . ?work dct:title ?title . ?work dct:created ?date .
FILTER (REGEX(STR(?date),'^2014')) } ORDER BY desc(?date)
Top subjects by year
SELECT (count(?sub) as ?tot) ?sub { ?work a frbr:Work . ?work dct:subject ?sub . ?work
dct:created ?date . FILTER (REGEX(STR(?date),'^2014')) } GROUP BY ?sub ORDER BY desc(?tot)
LIMIT 100
Example queries

W3C standards
http://www.w3.org/standards/semanticweb/
OKFN endpoints status (and list)
http://sparqles.okfn.org
LodLive (a SPRQL navigator)
http://en.lodlive.it
a very good intro to RDF
https://github.com/JoshData/rdfabout/blob/gh-pages/intro-to-rdf.md
Tim Berners-Lee’s “Linked Data – 5 stars ranking”
http://www.w3.org/DesignIssues/LinkedData.html
My github page
http://github.com/dvcama
My email
mailto:diego.camarda@regesta.com

SUMMER SCHOOL LEX 2014 - RDF + SPARQL querying the web of (lex)data

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SUMMER SCHOOL LEX 2014 - RDF + SPARQL querying the web of (lex)data