This document introduces linked data and discusses how publishing data as linked RDF triples on the web allows for a global linked database. It explains that linked data uses HTTP URIs to identify things and links data from different sources to be queried using SPARQL. Publishing linked data provides benefits like being able to integrate and discover related data on the web. Tools are available to convert existing data or publish new data as linked open data.

1. Introduction to Linked Data Consuming Linked Data Tutorial International Semantic Web Conference 2009

2. Do you SEARCH or do you FIND?

3. Search for Football Players who went to the University of Texas at Austin, played for the Dallas Cowboys as Cornerback

7. Why can’t we just FIND it…

10. Guess how I FOUND out?

11. I’ll tell you how I did NOT find it

12. Current Web = internet + links + docs

13. So what is the problem? The Web has problems People aren’t interested in documents They are interested in things People can parse documents and extract meaning Web pages are written in HTML HTML describes visualization of information Computers can’t!

14. 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 better find what we want

15. 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

16. RAW DATA!

17. But wait… don’t we do that already?

18. Current Data on the Web Relational Databases APIs XML CSV XLS … Can’t computers and applications already consume that data on the web?

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

20. This makes it hard to integrate data

21. The data in different data sources aren’t linked

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

23. Or if I create a mashup from different services, I have to learn different APIs and I get different formats of data back

24. Wouldn’t it be great if we had a standard way of publishing data on the Web?

25. We have a standardized way of publishing documents on the web, right? HTML

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

27. Good question! And the answer is YES. There is!

28. Resource Description Framework (RDF) A data model A way to model data i.e. Relational databases use relational 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 Semantic Web>

29. RDF can be serialized in different ways RDF/XML RDFa (RDF in HTML) N3 Turtle

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

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

32. An example

33. Document on the Web

34. Databases back up documents THINGS have PROPERTIES: A Book as a Title, an author, … This is a THING: A book title “Programming the Semantic Web” by Toby Segaran, …

35. Lets represent the data in RDF Programming the Semantic Web title author book Toby Segaran isbn 978-0-596-15381-6 publisher name Publisher O’Reilly

36. Remember that we are on the web Everything on the web is identified by a URI

37. And now let’s link the data to other data Programming the Semantic Web title author http://…/isbn978 Toby Segaran isbn 978-0-596-15381-6 publisher name http://…/publisher1 O’Reilly

38. And now consider the data from Revyu.com hasReview http://…/review1 http://…/isbn978 description reviewer Awesome Book http://…/reviewer name Juan Sequeda

39. Let’s start to link data hasReview http://…/review1 http://…/isbn978 Programming the Semantic Web title description sameAs hasReviewer Awesome Book author http://…/isbn978 Toby Segaran http://…/reviewer name isbn 978-0-596-15381-6 Juan Sequeda publisher name http://…/publisher1 O’Reilly

40. Juan Sequeda publishes data too http://juansequeda.com/id http://dbpedia.org/Austin livesIn name Juan Sequeda

41. Let’s link more data hasReview http://…/review1 http://…/isbn978 description hasReviewer Awesome Book http://…/reviewer name Juan Sequeda sameAs http://juansequeda.com/id http://dbpedia.org/Austin livesIn name Juan Sequeda

42. And more hasReview http://…/review1 http://…/isbn978 Programming the Semantic Web title description sameAs hasReviewer Awesome Book author http://…/isbn978 Toby Segaran http://…/reviewer name isbn 978-0-596-15381-6 Juan Sequeda publisher sameAs http://…/publisher1 name O’Reilly http://juansequeda.com/id http://dbpedia.org/Austin livesIn name Juan Sequeda

43. Data on the Web that is in RDF andislinked to other RDF data is LINKED DATA

44. Linked Data Principles Use URIs as names for things Use HTTP URIs so that people can look up (dereference) those names. When someone looks up a URI, provide useful information. Include links to other URIs so that they can discover more things.

45. Linked Data makes the web appear as ONEGIANTHUGEGLOBALDATABASE!

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

47. Yes! There is actually a standardize language for that SPARQL

48. FIND all the reviews on the book “Programming the Semantic Web” by people who live in Austin

49. hasReview http://…/review1 http://…/isbn978 Programming the Semantic Web title description sameAs hasReviewer Awesome Book author http://…/isbn978 Toby Segaran http://…/reviewer name isbn 978-0-596-15381-6 Juan Sequeda publisher sameAs name http://…/publisher1 O’Reilly http://juansequeda.com http://dbpedia.org/Austin livesIn name Juan Sequeda

50. This looks cool, but let’s be realistic. What is the incentive to publish Linked Data?

51. What was your incentive to publish an HTML page in 1990?

52. 1) Share data in documents2) Because you neighbor was doing it

53. So why should we publish Linked Data in 2009?

54. 1) Share data as data2) Because you neighbor is doing it

55. And guess who is starting to publish Linked Data now?

56. Linked Data Publishers 2009 UK Government US Government BBC Open Calais – Thomson Reuters Freebase NY Times Best Buy CNET Dbpedia Are you?

58. How can I publish Linked Data?

59. Publishing Linked Data Legacy Data in Relational Databases D2R Server Virtuoso Triplify Ultrawrap CMS Drupal Native RDF Stores Databases for RDF (Triple Stores) AllegroGraph, Jena, Sesame, Virtuoso Talis Platform (Linked Data in the Cloud) In HTML with RDFa

60. Questions?