The document discusses the evolution of the web from Web 1.0 to Web 3.0, highlighting the need for open data and linked data as methods for interlinking and enhancing the usability of structured data. It presents the D2R server as a tool for exposing relational databases and provides a case study on the VOA3R project, which integrates open content for researchers. The conclusions emphasize the shift towards a data-centric web and the role of RDF and linked data in fostering new applications.

1. Publishing Linked Data
from relational databases
Iván Ruiz Rube
Departamento de Lenguajes y Sistemas Informáticos
Universidad de Cádiz
09/11/2011 Jornadas de Software Libre y Web 2.0 1

2. Roadmap
 The evolution of the Web
 Linked Open Data
 Exposing databases with D2R Server
 Case study: The VOA3R Project
 Conclusions
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3. PUBLISHING LINKED DATA FROM RELATIONAL
DATABASES
THE EVOLUTION OF
THE WEB
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4. World Wide Web
 Most important infrastructure for the
distribution of information.
 Rich and broad information: text, images,
videos, slides, etc.
 Web navigators support HTML, JS, CSS
and other formats.
 Navigation based on hyperlinks.
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5. Web based on documents
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6. Web Evolution
Web 1.0 Web 2.0 Web 3.0
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7. Web 1.0
 Beginnings of the
Web
 Static pages
 Limited use of
standards
 Lack of interaction
with the user
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8. Web 2.0
 Higher bandwidth
 Standards
 Rich User Interface
 Accessibility
 Usability
 Social networks
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9. Web 3.0
 3D virtual
environments
 The Internet of
Things
 Domotics
 Cloud Computing
 Semantic Web
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10. Semantic Web
1Tim Berners-Lee
“I have a dream for the Web (in which computers) become
capable of analyzing all the data on the Web….”
“…the day-to-day mechanisms of trade, bureaucracy and
our daily lives will be handled by machines talking to
machines.”
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11. PUBLISHING LINKED DATA FROM RELATIONAL
DATABASES
LINKED OPEN DATA
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12. Information Age
 Huge amount of
information
 A large number of
information
systems
 Big challenges:
◦ Data integration
◦ Data analysis
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13. Need for open data
 Improvement of
organizational
transparency
 Public data
 Foster the
research
 Promote the
development of
third-party system
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14. Linked Open Data
“A method of publishing structured data so that it can be
interlinked and become more useful.
…it extends web pages to share information in a way that can
be read automatically by computers.”1
1Tim Berners-Lee 09/11/2011 Jornadas de Software Libre y Web 2.0 14

15. Resource Description Format
http://publisher.org/Papers/
Paper12345
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16. Resource Description Format
Linked Data -
The Story So Far
title
http://publisher.org/Papers/
Paper12345
year
2008
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17. Resource Description Format
Linked Data -
The Story So Far http://publisher.org/Journals/
JournalSWIS
title
publishedIn
http://publisher.org/Papers/
Paper12345
author http://w3.org/People/
Berners-Lee
year
2008
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18. Resource Description Format
Linked Data -
The Story So Far http://publisher.org/Journals/
JournalSWIS
title
publishedIn
http://w3c.org
http://publisher.org/Papers/ director
Paper12345
author http://w3.org/People/
Berners-Lee
year
type
2008 http://xmlns.com/foaf/
Person
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19. RDF (sintaxis)
<http://publisher.org/Papers/Paper12345>
title "Linked Data - The Story So Far";
year "2008-01-01";
author <http://w3.org/People/Berners-Lee>;
publishedIn <http://publisher.org/Journal/JournalSWIS> .
<rdf:Description
rdf:about="http://publisher.org/Papers/Paper12345">
<title>Linked Data - The Story So Far</title>
<year>2008-01-01</year>
<author rdf:resource="http://w3.org/People/Berners-Lee" />
<publishedIn
rdf:resource="http://publisher.org/Journal/JournalSWIS" />
</rdf:Description>
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20. Ontologies (vocabularies)
“An ontology is an explicit and formal specification of a shared
conceptualization1“
1Tom Gruber
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21. Linked Data Cloud
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22. PUBLISHING LINKED DATA FROM RELATIONAL
DATABASES
EXPOSING DATABASES
WITH D2R SERVER
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23. How is your data currently stored?
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24. How to publish Linked Data?
The Story
So Far
JournalSemanticWeb
 Annotation
◦ Manual
◦ Collaborative
LinkedData Berners-Lee
2008
W3C
◦ (Semi-)automatic
 Exposure
◦ RDF Triple Store
◦ HTML+RDF (RDFa)
◦ RDF Wrappers
◦ SQL2RDF
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25. Web Application Architecture
User Interface
Relational Application Server
Database
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26. Web Application Architecture using
D2R Server
Application
Server
Relational
Database
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27. Web Application Architecture using
D2R Server
Application
Server
<http://cris.org:/resource/projects/Organic>
a cerif:Project ;
rdfs:label "Multilingual Federation of Learning
Repositories"@en-uk ;
Relational cerif:acronym "Organic.Edunet" ;
cerif:endDate "2010-09-30"^^xsd:date ;
cerif:internalIdentifier
Database "ff808181300cf99e01300d1a355f0003"
cerif:isLinkedByOrganisationUnit
D2R
Server
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28. Web Application Architecture using
D2R Server
Application
Server
<http://cris.org:/resource/projects/Organic>
a cerif:Project ;
rdfs:label "Multilingual Federation of Learning
Repositories"@en-uk ;
Relational cerif:acronym "Organic.Edunet" ;
cerif:endDate "2010-09-30"^^xsd:date ;
cerif:internalIdentifier
Database "ff808181300cf99e01300d1a355f0003"
cerif:isLinkedByOrganisationUnit
D2R
Server
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29. Exposing and Consuming Linked
Data
Internet Navigator
File Favourites Help
URL: http://mashup.org
Relational D2R
Database Server
mashup
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30. Installing D2R
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31. Using D2R
~/d2rserver$> generate-mapping
-o MAPPING.n3
-d com.mysql.jdbc.Driver
-u USER -p PASSWORD
jdbc:mysql://localhost:3306/DATABASE
~/d2rserver$> d2r-server MAPPING.n3
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32. Database model example
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33. Vocabularies
#Built-in vocabularies
@prefix rdf: <http://www.w3.org/1999/02/22-rdf-syntax-ns#> .
@prefix rdfs: <http://www.w3.org/2000/01/rdf-schema#> .
@prefix xsd: <http://www.w3.org/2001/XMLSchema#> .
@prefix owl: <http://www.w3.org/2002/07/owl#> .
#Specific vocabularies
@prefix foaf: <http://xmlns.com/foaf/0.1/> .
@prefix dc: <http://purl.org/dc/elements/1.1/> .
@prefix dcterms: <http://purl.org/dc/terms/> .
@prefix bibo: <http://purl.org/ontology/bibo/> .
@prefix geo: <http://www.w3.org/2003/01/geo/wgs84_pos#> .
@prefix cerif: <http://eurocris.org/cerif#> .
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34. Database Connection
map:database a d2rq:Database;
# Main settings
d2rq:jdbcDriver "com.mysql.jdbc.Driver";
d2rq:jdbcDSN "jdbc:mysql://localhost:3306/DATABASE";
d2rq:username "USER";
d2rq:password "PASSWORD";
# Other settings
jdbc:autoReconnect "true";
jdbc:zeroDateTimeBehavior "convertToNull";
d2rq:allowDistinct "true";
jdbc:keepAlive "3600"; # value in seconds
jdbc:keepAliveQuery "SELECT 1";
.
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35. Exposing RDF Resources
map:OrganisationUnits a d2rq:ClassMap;
d2rq:dataStorage map:database;
d2rq:class cerif:Organization;
d2rq:uriPattern
"organizations/@@ORGANISATIONS.ACRONYM@@";
d2rq:condition "ORGANISATIONS.ACRONYM <> ''“ .
http://dataset.org/organizations/
UCA
rdf:type
http://eurocris.org/cerif/
Organization
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36. Exposing literal properties
map:OrganisationUnits_Headcount a d2rq:PropertyBridge;
d2rq:belongsToClassMap map:OrganisationUnits;
d2rq:property cerif:headcount;
d2rq:column "ORGANISATIONS.HEADCOUNT “ .
http://dataset.org/organizations/
UCA
cerif:headcount
2400
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37. Exposing 1:N relations
map:OrganisationUnits_Name a d2rq:PropertyBridge;
d2rq:belongsToClassMap map:OrganisationUnits;
d2rq:property cerif:name;
d2rq:join "ORG_NAME.ORGID = ORGANISATIONS.ID";
d2rq:column "ORG_NAME.NAME“ .
http://dataset.org/organizations/
UCA
cerif:name
cerif:name
Universidad
de Cádiz@es
University of
Cádiz@en
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38. Exposing N:M relations
map:OrganisationUnits_Person a d2rq:PropertyBridge;
d2rq:belongsToClassMap map:OrganisationUnits;
d2rq:property cerif:members;
d2rq:join "ORG_PERS.ORGID = ORGANISATIONS.ID";
d2rq:join "ORG_PERS.PERSID = PERSON.ID";
d2rq:refersToClassMap map:Person .
http://dataset.org/organizations/
UCA
cerif:members
http://dataset.org/people/
InvestigadorXYZ
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39. PUBLISHING LINKED DATA FROM RELATIONAL
DATABASES
CASE STUDY:THE
VOA3R PROJECT
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40.  Platform based on semantic technologies
to integrate open contents for
researchers.
 Manages scientific context:
◦ Organizations
◦ Research Projects
◦ Researcher Profiles
◦ etc.
 Publishes its data using D2R Server.
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41. VOA3R Portal
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42. Organization’s Data in VOA3R
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43. Organization’s Data in RDF
<http://voa3r.cc.uah.es/dataset/resource/organisationUnits/UAH>
rdf:type cerif:OrganisationUnit ;
rdfs:label "University of Alcala" ;
cerif:acronym "UAH" ;
foaf:homepage <http://www.uah.es> ;
cerif:researchActivities "Ontologies, Linked Data" ;
dcterms:subject <http://aims.fao.org/aos/agrovoc/c_7273> ,
<http://aims.fao.org/aos/agrovoc/c_8070> ;
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44. Organization’s Data in RDF (II)
…
cerif:researchProjects
<http://voa3r.cc.uah.es/dataset/resource/projects/Organic.Edunet> ,
<http://voa3r.cc.uah.es/dataset/resource/projects/Organic.Lingua> ,
<http://voa3r.cc.uah.es/dataset/resource/projects/VOA3R> ;
cerif:innerGroups
<http://voa3r.cc.uah.es/dataset/resource/organisationUnits/IERU> ;
cerif:members
<http://voa3r.cc.uah.es/dataset/resource/person/Salvador_Sanchez> ,
<http://voa3r.cc.uah.es/dataset/resource/person/Miguel_Refusta> ,
<http://voa3r.cc.uah.es/dataset/resource/person/Luis_Torrico> .
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45. Organization’s Data via D2R
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46. SPARQL Client
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47. PUBLISHING LINKED DATA FROM RELATIONAL
DATABASES
CONCLUSIONS
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48. Conclusions
 Web based on documents  Web based on
Data.
 Linked Data as a way for interchanging data
between different datasets in the Web.
 RDF as a standard format to describe data.
 D2R allows to publish RDF metadata from
databases (non-intrusive technique).
 Main aim: Create new third-party
applications using open linked data from LD
systems.
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49. References
 Linked Data: Evolving the Web into a
Global Data Space
◦ http://linkeddatabook.com/
 W3C Linking Open Data Project
◦ http://www.w3.org/wiki/SweoIG/TaskForces/C
ommunityProjects/LinkingOpenData
 D2R Server
◦ http://www4.wiwiss.fu-berlin.de/bizer/d2r-
server
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50. Publishing Linked Data from
relational databases
thanks
Iván Ruiz Rube
ivan.ruiz@uca.es
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