introduction to linked data -

Introduc)on to Linked Data

Consuming Linked Data Tutorial World Wide Web Conference 2010

Do you SEARCH or do you FIND?

Search for

Football Players who went to the University of Texas at Aus)n, played for the Dallas Cowboys as Cornerback

Why can’t we just FIND it…

Guess how I FOUND out?

I’ll tell you how I did NOT find it

Current Web = internet + links + docs

So what is the problem?

•  The Web has problems – People aren’t interested in documents •  They are interested in things (that are in documents)

– People can parse documents and extract meaning • Web pages are wriXen in HTML •  HTML describes visualiza)on of informa)on

•  Computers can’t!

What do we need to do?

•  We need to help machines to understand the web so machines can help us understand things – They can learn what we are interested in – They can help us beXer find what we want

How can we do that?

•  Besides publishing documents on the web – which computers can’t understand easily

•  Let’s publish something that computers can understand

RAW DATA!

But wait… don’t we do that already?

Current Data on the Web

•  Rela)onal Databases •  APIs •  XML •  CSV •  XLS •  … •  Can’t computers and applica)ons already consume that data on the web?

True! But it is all in different formats and data models!

This makes it hard to integrate data

The data in different data sources aren’t linked

For example, how do I know that the Juan Sequeda in Facebook is the same as Juan Sequeda in TwiXer

Or if I create a mashup from different services, I have to learn different APIs and I get different

formats of data back

Wouldn’t it be great if we had a standard way of publishing data on

the Web?

We have a standardized way of publishing documents on the web,

right? HTML

Then why can’t we have a standard way of publishing data on the Web?

Good ques)on! And the answer is YES. There is!

Resource Descrip)on Framework (RDF)

•  A data model – A way to model data –  i.e. Rela)onal databases use rela)onal data model

•  RDF is a triple data model •  Labeled Graph •  Subject, Predicate, Object •  <Juan> <was born in> <California> •  <California> <is part of> <the USA> •  <Juan> <likes> <the Seman)c Web>

RDF can be serialized in different ways

•  RDF/XML •  RDFa (RDF in HTML)

•  N3 •  Turtle •  JSON

So does that mean that I have to publish my data in RDF now?

You don’t have to… but we would like you to

An example

Document on the Web

Databases back up documents

Isbn Title Author PublisherID ReleasedData

978-‐0-‐596-‐15381-‐6

Programming the Seman.c Web

Toby Segaran 1 July 209

… … … … …

PublisherID PublisherName

1 O’Reilly Media

… …

This is a THING: A book )tle “Programming the Seman)c Web” by Toby Segaran, …

THINGS have PROPERTIES: A Book as a Title, an author, …

Lets represent the data in RDF

book

Programming the Seman)c Web

978-‐0-‐596-‐15381-‐6

Toby Segaran

Publisher O’Reilly

)tle

name

author

publisher

isbn

Remember that we are on the web

Everything on the web is iden)fied by a URI

And now let’s link the data to other data

hXp://…/isbn978


978-‐0-‐596-‐15381-‐6

Toby Segaran

hXp://…/publisher1 O’Reilly

)tle

name

author

publisher

isbn

And now consider the data from Revyu.com

hXp://…/isbn978

hXp://…/review1

Awesome Book

hXp://…/reviewer

Juan Sequeda

hasReview

reviewer

descrip)on

name

Let’s start to link data

hXp://…/isbn978


978-‐0-‐596-‐15381-‐6

Toby Segaran


)tle

name

author

publisher

isbn

hXp://…/isbn978

sameAs

hXp://…/review1

Awesome Book

hXp://…/reviewer

Juan Sequeda

hasReview

hasReviewer

descrip)on

name

Juan Sequeda publishes data too

hXp://juansequeda.

com/id

livesIn

Juan Sequeda name

hXp://dbpedia.org/Aus)n

Let’s link more data hXp://…/isbn978

hXp://…/review1

Awesome Book

hXp://…/reviewer

Juan Sequeda

hXp://juansequeda.

com/id

hasReview

hasReviewer

descrip)on

name

sameAs

livesIn

Juan Sequeda name


And more

hXp://…/isbn978


978-‐0-‐596-‐15381-‐6

Toby Segaran

hXp://…/publisher1

O’Reilly

)tle

name

author

publisher

isbn

hXp://…/isbn978

sameAs

hXp://…/review1

Awesome Book

hXp://…/reviewer

Juan Sequeda

hXp://juansequeda.

com/id

hasReview

hasReviewer

descrip)on

name

sameAs

livesIn

Juan Sequeda name


Data on the Web that is in RDF and is linked to other RDF data is LINKED

DATA

Linked Data Principles

1.  Use URIs as names for things

2.  Use HTTP URIs so that people can look up (dereference) those names.

3.  When someone looks up a URI, provide useful informa)on.

4.  Include links to other URIs so that they can discover more things.

Linked Data makes the web appear as ONE GIANT HUGE

GLOBAL DATABASE!

I can query a database with SQL. Is there a way to query Linked Data

with a query language?

Yes! There is actually a standardize language for that

SPARQL

FIND all the reviews on the book “Programming the Seman)c Web”

by people who live in Aus)n

hXp://…/isbn978


978-‐0-‐596-‐15381-‐6

Toby Segaran


)tle

name

author

publisher

isbn

hXp://…/isbn978

sameAs

hXp://…/review1

Awesome Book

hXp://…/reviewer

Juan Sequeda

hXp://juansequeda.

com

hasReview

hasReviewer

descrip)on

name

sameAs

livesIn

Juan Sequeda name


This looks cool, but let’s be realis)c. What is the incen)ve to publish

Linked Data?

What was your incen)ve to publish an HTML page in 1990?

1) Share data in documents 2) Because you neighbor was doing it

So why should we publish Linked Data in 2010?

1) Share data as data 2) Because you neighbor is doing it

And guess who is star)ng to publish Linked Data now?

Linked Data Publishers

•  UK Government •  US Government •  BBC •  Open Calais – Thomson Reuters •  Freebase •  NY Times •  Best Buy •  CNET •  Dbpedia •  Are you?

How can I publish Linked Data?

Publishing Linked Data •  Legacy Data in Rela)onal Databases – D2R Server –  Virtuoso –  Triplify – Ultrawrap

•  CMS – Drupal 7

•  Na)ve RDF Stores – Databases for RDF (Triple Stores)

•  AllegroGraph, Jena, Sesame, Virtuoso –  Talis Plauorm (Linked Data in the Cloud)

•  In HTML with RDFa

Ques)ons?

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