Download pdf - Publishing linked data from relational databases

Iván Ruiz Rube Departamento de Lenguajes y Sistemas Informáticos

Universidad de Cádiz

09/11/2011 1

Publishing Linked Data

from relational databases

Jornadas de Software Libre y Web 2.0

Roadmap

The evolution of the Web

Linked Open Data

Exposing databases with D2R Server

Case study: The VOA3R Project

Conclusions

09/11/2011 2 Jornadas de Software Libre y Web 2.0

THE EVOLUTION OF THE WEB

PUBLISHING LINKED DATA FROM RELATIONAL DATABASES


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.


Web based on documents


Web Evolution

09/11/2011 6

Web 1.0 Web 2.0 Web 3.0


Web 1.0

Beginnings of the

Web

Static pages

Limited use of

standards

Lack of interaction

with the user


Web 2.0

Higher bandwidth

Standards

Rich User Interface

Accessibility

Usability

Social networks


Web 3.0

3D virtual

environments

The Internet of

Things

Domotics

Cloud Computing

Semantic Web


Semantic Web

09/11/2011 10

“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.”

1Tim Berners-Lee


LINKED OPEN DATA



Information Age

Huge amount of

information

A large number of

information

systems

Big challenges: ◦ Data integration

◦ Data analysis


Need for open data

Improvement of

organizational

transparency

Public data

Foster the

research

Promote the

development of

third-party system


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

09/11/2011 Jornadas de Software Libre y Web 2.0 14

1Tim Berners-Lee

Resource Description Format

http://publisher.org/Papers/

Paper12345



2008

year

Linked Data -

The Story So Far

title


Paper12345



author

publishedIn

2008

http://publisher.org/Journals/

JournalSWIS

year

Linked Data -

The Story So Far

title

http://w3.org/People/

Berners-Lee


Paper12345



author

publishedIn

2008

http://publisher.org/Journals/

JournalSWIS

year

http://w3c.org

director

Linked Data -

The Story So Far

title

http://w3.org/People/

Berners-Lee


Paper12345


http://xmlns.com/foaf/

Person

type

RDF (sintaxis)

09/11/2011 19

<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>


Ontologies (vocabularies)

09/11/2011 20

“An ontology is an explicit and formal specification of a shared

conceptualization1“

1Tom Gruber


Linked Data Cloud


EXPOSING DATABASES WITH D2R SERVER



How is your data currently stored?


How to publish Linked Data?

Annotation

◦ Manual

◦ Collaborative

◦ (Semi-)automatic

Exposure

◦ RDF Triple Store

◦ HTML+RDF (RDFa)

◦ RDF Wrappers

◦ SQL2RDF


2008

JournalSemanticWeb

W3C

The Story

So Far

Berners-Lee LinkedData

Web Application Architecture

09/11/2011 25

Relational

Database Application Server

User Interface


Web Application Architecture using

D2R Server

09/11/2011 26

Relational

Database

Application

Server



D2R Server

09/11/2011 27

<http://cris.org:/resource/projects/Organic>

a cerif:Project ;

rdfs:label "Multilingual Federation of Learning

Repositories"@en-uk ;

cerif:acronym "Organic.Edunet" ;

cerif:endDate "2010-09-30"^^xsd:date ;

cerif:internalIdentifier

"ff808181300cf99e01300d1a355f0003"

cerif:isLinkedByOrganisationUnit

Relational

Database

D2R

Server

Application

Server



D2R Server

09/11/2011 28

<http://cris.org:/resource/projects/Organic>

a cerif:Project ;

rdfs:label "Multilingual Federation of Learning

Repositories"@en-uk ;

cerif:acronym "Organic.Edunet" ;

cerif:endDate "2010-09-30"^^xsd:date ;

cerif:internalIdentifier

"ff808181300cf99e01300d1a355f0003"

cerif:isLinkedByOrganisationUnit

Relational

Database

D2R

Server

Application

Server


Exposing and Consuming Linked

Data

Internet Navigator

URL: http://mashup.org File Favourites Help

mashup

D2R

Server Relational

Database


Installing D2R


Using D2R

~/d2rserver$> generate-mapping

-o MAPPING.n3

-d com.mysql.jdbc.Driver

-u USER -p PASSWORD

jdbc:mysql://localhost:3306/DATABASE

09/11/2011 31

~/d2rserver$> d2r-server MAPPING.n3


Database model example


Vocabularies

09/11/2011 33

#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#> .


Database Connection

09/11/2011 34

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";

.


Exposing RDF Resources

09/11/2011 35

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

http://eurocris.org/cerif/

Organization

rdf:type

Exposing literal properties

09/11/2011 36

map:OrganisationUnits_Headcount a d2rq:PropertyBridge;

d2rq:belongsToClassMap map:OrganisationUnits;

d2rq:property cerif:headcount;

d2rq:column "ORGANISATIONS.HEADCOUNT “ .



UCA

cerif:headcount

2400

Exposing 1:N relations

09/11/2011 37

map:OrganisationUnits_Name a d2rq:PropertyBridge;


d2rq:property cerif:name;

d2rq:join "ORG_NAME.ORGID = ORGANISATIONS.ID";

d2rq:column "ORG_NAME.NAME“ .



UCA

cerif:name

University of

Cádiz@en

Universidad

de Cádiz@es

cerif:name

Exposing N:M relations

09/11/2011 38

map:OrganisationUnits_Person a d2rq:PropertyBridge;


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/people/

InvestigadorXYZ


UCA

cerif:members

CASE STUDY: THE VOA3R PROJECT



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.


VOA3R Portal


Organization’s Data in VOA3R


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> ;


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> .


Organization’s Data via D2R


SPARQL Client


CONCLUSIONS



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. 09/11/2011 48 Jornadas de Software Libre y Web 2.0

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


http://linkeddatabook.com/

http://www.w3.org/wiki/SweoIG/TaskForces/CommunityProjects/LinkingOpenData

http://www.w3.org/wiki/SweoIG/TaskForces/CommunityProjects/LinkingOpenData

http://www4.wiwiss.fu-berlin.de/bizer/d2r-server





Iván Ruiz Rube [email protected]

09/11/2011 50

Publishing Linked Data from

relational databases

thanks
