Semantic Web in Action:           Web 3.0, Social Web       Linked Data, Be Aware!S. Garlatti10/09/09
Outline         ¢  Semantic   Web         ¢  Linked   Data         ¢  SPARQLpage 2                        Semantic Web ...
Technological Issues           an Informal learning case         •  I plan to ride in Europe for vacation, on a           ...
Who is teaching at Telecom Bretagne and         riding a motorcycle across Europe?page 4                 Semantic Web in A...
Technological Issues         •  Google Information retrieval            –  Query : « teacher » « riding » « Europe »      ...
Search in Telecom Bretagne Web Sitepage 6                 Semantic Web in Action
Search in Motorcycle Web Sitespage 7                 Semantic Web in Action
Search in Picture Web Sites with         Geolocalizationpage 8                 Semantic Web in Action
Technological Issues         •  Relevance of resources?            –  Human interpretation         •  Reuse, exchange and ...
Semantic Web¢    The Semantic Web is a web of data.       •  There is lots of data we all use every day, and it is not pa...
Semantic Web          ¢  The   Semantic Web is about two things.              -  It is about common formats for integrati...
Semantic Web          ¢  The   Semantic Web            •  That allows a person, or a machine, to start off in            ...
The Semantic Web     ¢  The   Semantic Web is about two things.           -  It is about common formats for integration a...
The Semantic Web     ¢  That  allows a person, or a machine, to start off in          one database, and then move through...
Linked Data          ¢  Classic   Web            •  Data exposed to the web via HTML            •  Web Pages Found via se...
The Semantic Web          •  Resource Description             –  Similar to simple sentence                •  Subject Verb...
The Semantic Web          •  Sentence meaning            –  Different contexts à Different terms               •  « direc...
The Semantic Web          •  A little bit more formal             –  Telecom Bretagne dbpprop:president XXX (en)          ...
Linked Data Who is teaching at Telecom Bretagne  and riding a motorcycle  across Europe?page 19                       Sema...
Linked Data ¢  Trouver       Tous les films          -  Du genre « Thriller »          -  ET classés au moins quatre     ...
page 21
Linked Data     Web 1.0                                   Web 2.0                                         Web 3.0Many	  We...
Linked Data          ¢  Linked   Data            •  Is a term used to describe a method of exposing, sharing, and        ...
Linked Data          ¢    Tim Berners-Lee outlined four principles of Linked Data in                his Design Issues: Li...
Linked Data          ¢  Linking   Open Data Community Project            •  The goal of the W3C Semantic Web Education an...
Le Google Intelligent : Comment ?page 26
Linked Data          ¢    Resources                •    http://esw.w3.org/topic/SweoIG/TaskForces/CommunityProjects/Linki...
Linked Data          ¢  DBpedia                •  Is a community effort to extract structured information from           ...
Linked Data          ¢  Examples           •  THING à http://dbpedia.org/page/Brest%2C_France           •  HTML à http:...
Linked Data          ¢  Dbpedia   Sparql Endpoint           •  Langage de requêtes SPARQL           •  http://dbpedia.org...
Linked Data          ¢    FREEBASE                Website http://www.freebase.com/                http://www.freebase.com...
Linked Data¢  Semantic   CrunchBase •    The free directory of technology companies,      people, and investors. •    htt...
Linked Data¢  Les   Smob : les Twitter version Web sémantique  •  http://www.lespetitescases.net/smob-twitter-version-web...
Linked Data          ¢  IMDB,   Linked Movie Database http://www.linkedmdb.org/             •  LinkedMDB publishes linked...
Linked Data          ¢  Musicbrainz           •  This is a database published with D2R Server. It can              be acc...
Linked Data          ¢  GovTrack.us           •  A civic project to track congress           •  The 2000 U.S. Census: 1 B...
Linked Data          ¢  GovTrack.us           •    The SPARQL engines base URL is                http://www.rdfabout.com/...
Linked Data          ¢  Revyu.com           •  Revyu.com is a web site where you can review and rate things.             ...
SPARQL: SPARQL Protocol and RDF Query                Language          ¢    SPARQL                •  pronounced "sparkle"...
SPARQL: SPARQL Protocol and RDF Query           Language          ¢  SPARQL   =           •  A Query Language           •...
SPARQL: SPARQL Protocol and RDF Query            Language          ¢  The   Query Language: query forms            •  « S...
SPARQL: SPARQL Protocol and RDF Query            Language          ¢  «Select » equivalent to « SQL Select » returns a   ...
SPARQL: SPARQL Protocol and RDF Query                Language          ¢    PREFIX foaf: <http://xmlns.com/foaf/0.1/>    ...
SPARQL: SPARQL Protocol and RDF Query                Language   ¢          PREFIX   foaf: <http://xmlns.com/foaf/0.1/>   ...
SPARQL: SPARQL Protocol and RDF Query             Language¢  SPARQL        results:¢    namebirthperson« ":Dru_Berrymore...
SPARQL: SPARQL Protocol and RDF Query                Language          ¢    SELECT distinct ?name ?person                ...
SPARQL: SPARQL Protocol and RDF Query            Language          ¢  A              constraint, expressed by the keyword...
SPARQL: SPARQL Protocol and RDF Query          Language          ¢  “regex”  matches only plain literals with no         ...
SPARQL: SPARQL Protocol and RDF Query                Language          ¢  Optional   parts of the graph pattern may be   ...
SPARQL: SPARQL Protocol and RDF Query          Language           ¢  Matching     alternative                 •  Pattern ...
SPARQL: SPARQL Protocol and RDF Query             Language¢  Sequence      & Modify      •  « Order By » to sort,      • ...
SPARQL: SPARQL Protocol and RDF Query            Language          ¢  «   Construct »             •  The CONSTRUCT query ...
SPARQL: SPARQL Protocol and RDF Query            Language   ¢    PREFIX foaf: <http://xmlns.com/foaf/0.1/>         FROM <...
SPARQL: SPARQL Protocol and RDF Query                Language          ¢  ASK                •  Returns a true/false valu...
SPARQL: SPARQL Protocol and RDF Query                Language          ¢  DESCRIBE                •  The DESCRIBE form re...
SPARQL: SPARQL Protocol and RDF Query           Language          ¢  Applied   uses (from Ingenta)            •  DESCRIBE...
SPARQL: SPARQL Protocol and RDF Query           Language          ¢  Applied   uses (from Ingenta)            •  CONSTRUC...
SPARQL: SPARQL Protocol and RDF Query           Language          ¢  SPARQL    Protocol (from F. Gandon, INRIA)          ...
SPARQL: SPARQL Protocol and RDF Query                Language          ¢  Example       with SOAP binding (from F. Gandon...
SPARQL: SPARQL Protocol and RDF Query                Language          ¢  Access       to Data on the web                ...
SPARQL: SPARQL Protocol and RDF Query           Language          ¢  Resources           •  http://en.wikipedia.org/wiki/...
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Social web & linked data

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ISITC Hammam Sousse

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Social web & linked data

  1. 1. Semantic Web in Action: Web 3.0, Social Web Linked Data, Be Aware!S. Garlatti10/09/09
  2. 2. Outline ¢  Semantic Web ¢  Linked Data ¢  SPARQLpage 2 Semantic Web in Action
  3. 3. Technological Issues an Informal learning case •  I plan to ride in Europe for vacation, on a motorcycle. –  I need to learn more about travelling on motorcycle across Europe •  Rider’s apparel: boots, jackets, pants, gloves, armor, etc. •  Motorcycle accessories: luggages, side cases, topcases, tank bags, GPS, etc. •  Riding issues, skills, etc. –  According to my social networks, I know there is a teacher at Telecom Bretagne who used to ride across Europepage 3 Semantic Web in Action
  4. 4. Who is teaching at Telecom Bretagne and riding a motorcycle across Europe?page 4 Semantic Web in Action
  5. 5. Technological Issues •  Google Information retrieval –  Query : « teacher » « riding » « Europe » « Motorbike » •  613 000 results •  How to find out relevant resources? •  Polysemy •  Huge number of results!page 5 Semantic Web in Action
  6. 6. Search in Telecom Bretagne Web Sitepage 6 Semantic Web in Action
  7. 7. Search in Motorcycle Web Sitespage 7 Semantic Web in Action
  8. 8. Search in Picture Web Sites with Geolocalizationpage 8 Semantic Web in Action
  9. 9. Technological Issues •  Relevance of resources? –  Human interpretation •  Reuse, exchange and sharing of resources –  Computer would have the ability to get content meaning! –  impossible?page 9 Semantic Web in Action
  10. 10. Semantic Web¢  The Semantic Web is a web of data. •  There is lots of data we all use every day, and it is not part of the web. •  I can see my bank statements on the web, and my photographs, and I can see my appointments in a calendar. •  But can I see my photos in a calendar to see what I was doing when I took them? •  Can I see bank statement lines in a calendar?¢  Why not? •  Because we dont have a web of data. •  Because data is controlled by applications, and each application keeps it to itself. Semantic Web in Action
  11. 11. Semantic Web ¢  The Semantic Web is about two things. -  It is about common formats for integration and combination of data drawn from diverse sources -  On the contrary, the original Web is mainly concentrated on the interchange of documents. -  It is also about language for recording how the data relates to real world objects (meaning).page 11 Semantic Web in Action
  12. 12. Semantic Web ¢  The Semantic Web •  That allows a person, or a machine, to start off in one database, and then move through an unending set of databases which are connected not by wires but by being about the same thing. •  Provides a common framework that allows data to be shared and reused across application, enterprise, and community boundariespage 12 Semantic Web in Action
  13. 13. The Semantic Web ¢  The Semantic Web is about two things. -  It is about common formats for integration and combination of data drawn from diverse sources -  On the contrary, the original Web is mainly concentrated on the interchange of documents. -  It is also about language for recording how the data relates to real world objects (meaning).page 13 Semantic Web in Action
  14. 14. The Semantic Web ¢  That allows a person, or a machine, to start off in one database, and then move through an unending set of databases which are connected not by wires but by being about the same thing. ¢  Provides a common framework that allows data to be shared and reused across application, enterprise, and community boundaries ¢  The Semantic Web will enable machines to COMPREHEND semantic documents and data, not human speech and writings.page 14 Semantic Web in Action
  15. 15. Linked Data ¢  Classic Web •  Data exposed to the web via HTML •  Web Pages Found via search engines ¢  What do we actually want? •  Use the web like a Single Global Database •  Ask Complex Queries over multiples pages / web sites / data sourcespage 15 Semantic Web in Action
  16. 16. The Semantic Web •  Resource Description –  Similar to simple sentence •  Subject Verb Complement –  Examples •  Telecom Bretagne has a president called XXX •  Telecom Bretagne is a French grande ecole •  Telecom Bretagne has a web site http://www.tele...page 16 Semantic Web in Action
  17. 17. The Semantic Web •  Sentence meaning –  Different contexts à Different terms •  « director », « president », « Dean », … –  Meaning linked to communities of practices •  Use of common vocabularies! •  Named: Ontologies •  An ontology determine a unique meaning to verbs and categories of subject and complementpage 17 Semantic Web in Action
  18. 18. The Semantic Web •  A little bit more formal –  Telecom Bretagne dbpprop:president XXX (en) –  Telecom Bretagne dbpprop:type French Grande Ecole (en) –  Telecom Bretagne dbpprop:website http://www.tele... •  Queries –  French Grande Ecole in which XXX is president? •  ?Grande_Ecole dbpprop:president XXX (en) •  ?Grande_Ecole dbpprop:type French Grande Ecole (en)page 18 Semantic Web in Action
  19. 19. Linked Data Who is teaching at Telecom Bretagne and riding a motorcycle across Europe?page 19 Semantic Web in Action
  20. 20. Linked Data ¢  Trouver Tous les films -  Du genre « Thriller » -  ET classés au moins quatre par -  ET appréciés au moins par quatre de mes amis –  OU ceux qui me suivent sur -  ET dont Leonardo Di Caprio n’est pas un des acteurs ?page 20
  21. 21. page 21
  22. 22. Linked Data Web 1.0 Web 2.0 Web 3.0Many  Web  sites   Few  large  Web  sites   Many  Web  sites  ontaining  unstructured,   are  specialized  on   containing  &  seman<cally  extual  content   specific  content  types   syndica<ng  arbitrarily   structured  content   Video   Pictures   Encyclopedic   +   ar3cles   +   Source  :  Dr. Sören Auer AKSW, Institut für Informatik page 22 Computer Science Department Semantic Web in Action
  23. 23. Linked Data ¢  Linked Data •  Is a term used to describe a method of exposing, sharing, and connecting data on the Web via dereferenceable URIs. ¢  Principles (Tim Berners-Lee) •  The Semantic Web isnt just about putting data on the web. It is about making links, so that a person or machine can explore the web of data. With linked data, when you have some of it, you can find other, related, data. •  Like the web of hypertext, the web of data is constructed with documents on the web. However, unlike the web of hypertext, where links are relationships anchors in hypertext documents written in HTML, for data they links between arbitrary things described by RDF. The URIs identify any kind of object or concept. Source : Wikipedia, Tim Berners Leepage 23 Semantic Web in Action
  24. 24. Linked Data ¢  Tim Berners-Lee outlined four principles of Linked Data in his Design Issues: Linked Data note, paraphrased along the following lines: •  Use URIs to identify things that you expose to the Web as resources. •  Use HTTP URIs so that people can locate and look up (dereference) these things. •  Provide useful information about the resource when its URI is dereferenced. •  Include links to other, related URIs in the exposed data as a means of improving information discovery on the Web.page 24 Semantic Web in Action
  25. 25. Linked Data ¢  Linking Open Data Community Project •  The goal of the W3C Semantic Web Education and Outreach groups Linking Open Data community project is to extend the Web with a data commons by publishing various open datasets as RDF on the Web and by setting RDF links between data items from different data sources. As of October 2007, datasets consist of over two billion RDF triples, which are interlinked by over two million RDF links. (Wikipedia)page 25 Semantic Web in Action
  26. 26. Le Google Intelligent : Comment ?page 26
  27. 27. Linked Data ¢  Resources •  http://esw.w3.org/topic/SweoIG/TaskForces/CommunityProjects/LinkingOpenData/ •  http://esw.w3.org/topic/TaskForces/CommunityProjects/LinkingOpenData/DataSets •  http://esw.w3.org/topic/TaskForces/CommunityProjects/LinkingOpenData/ CommonVocabularies •  http://en.wikipedia.org/wiki/Linked_Data •  http://www.w3.org/DesignIssues/LinkedData.html •  http://events.linkeddata.org/iswc2008tutorial/ •  http://www4.wiwiss.fu-berlin.de/bizer/pub/LinkedDataTutorial/page 27
  28. 28. Linked Data ¢  DBpedia •  Is a community effort to extract structured information from Wikipedia and to make this information available on the Web. DBpedia allows you to ask sophisticated queries against Wikipedia, and to link other data sets on the Web to Wikipedia data. ¢  Resources •  http://wiki.dbpedia.org/About •  http://blog.dbpedia.org/ •  http://www4.wiwiss.fu-berlin.de/dbpedia/dev/ontology.htmpage 28 Semantic Web in Action
  29. 29. Linked Data ¢  Examples •  THING à http://dbpedia.org/page/Brest%2C_France •  HTML à http://dbpedia.org/resource/Brest%2C_France •  RDF à http://dbpedia.org/data/Brest%2C_France •  http://dbpedia.org/page/%C3%89cole_nationale_sup %C3%A9rieure_des_t%C3%A9l %C3%A9communications_de_Bretagne •  http://dbpedia.org/page/Amy_Winehouse •  http://dbpedia.org/page/Berlinpage 29 Semantic Web in Action
  30. 30. Linked Data ¢  Dbpedia Sparql Endpoint •  Langage de requêtes SPARQL •  http://dbpedia.org/snorql/ * •  http://dbpedia.org/sparql •  Twinkle : a sparql query tool -  http://www.ldodds.com/projects/twinkle/page 30 Semantic Web in Action
  31. 31. Linked Data ¢  FREEBASE Website http://www.freebase.com/ http://www.freebase.com/docs/data •  View data about New York -  http://www.freebase.com/view/en/new_york •  RDF metadata about New York -  http://rdf.freebase.com/rdf/en.new_york •  Edit New York Topic -  http://www.freebase.com/edit/topic/en/new_york •  Explore New York Metadata -  http://www.freebase.com/tools/explore/en/new_york Semantic Web in Actionpage 31
  32. 32. Linked Data¢  Semantic CrunchBase •  The free directory of technology companies, people, and investors. •  http://cb.semsol.org/ •  http://cb.semsol.org/sparql •  http://cb.semsol.org/company/techcrunch •  http://cb.semsol.org/product/facebook-platform •  http://cb.semsol.org/explore Semantic Web in Action
  33. 33. Linked Data¢  Les Smob : les Twitter version Web sémantique •  http://www.lespetitescases.net/smob-twitter-version-web- semantique/ •  http://smob.websemantique.org/sparql.php •  http://microplanet.sioc-project.org/sparql.php Semantic Web in Action
  34. 34. Linked Data ¢  IMDB, Linked Movie Database http://www.linkedmdb.org/ •  LinkedMDB publishes linked open data using the D2R Server. The project aims at publishing the first open semantic web database for movies, including a large number of interlinks to several datasets on the open data cloud and references to related webpages ¢  Data can be accessed using •  Web browsers: http://www.linkedmdb.org/ •  Semantic Web browsers - entry point: http://data.linkedmdb.org/all •  SPARQL clients - SPARQL endpoint: http://data.linkedmdb.org/sparqlpage 34 Semantic Web in Action
  35. 35. Linked Data ¢  Musicbrainz •  This is a database published with D2R Server. It can be accessed using -  Your web browser http://dbtune.org/musicbrainz/ -  Semantic Web browsers at URL http://dbtune.org/musicbrainz/all -  SPARQL clients at URL http://dbtune.org/musicbrainz/sparql or In a web browser http://dbtune.org/musicbrainz/snorql/page 35 Semantic Web in Action
  36. 36. Linked Data ¢  GovTrack.us •  A civic project to track congress •  The 2000 U.S. Census: 1 Billion RDF Triples •  http://www.rdfabout.com/demo/census/ •  http://www.govtrack.us/developers/rdf.xpd •  The SPARQL endpoint is a combined endpoint for various RDF data I play with. It answers queries about 1 billion triples, mostly about U.S. Census data (see rdfabout.com), but also the GovTrack data.page 36 Semantic Web in Action
  37. 37. Linked Data ¢  GovTrack.us •  The SPARQL engines base URL is http://www.rdfabout.com/sparql , following (or trying to follow) the SPARQL Protocol spec. •  The SPARQL engine is Ryan Leverings engine for SESAME, plus my SemWeb library for C#. •  The data store is persisted in MySQL. Responses are limited to 1000 rows in the hopes that having this public wont break anything.page 37 Semantic Web in Action
  38. 38. Linked Data ¢  Revyu.com •  Revyu.com is a web site where you can review and rate things. Unlike many other reviewing sites on the web, Revyu.com lets you review and rate absolutely anything you can name •  Web access: http://revyu.com/ •  SPARQL Endpoint http://revyu.com/sparql/page 38 Semantic Web in Action
  39. 39. SPARQL: SPARQL Protocol and RDF Query Language ¢  SPARQL •  pronounced "sparkle" [1]) is an RDF query language; its name is a recursive acronym that stands for SPARQL Protocol and RDF Query Language. It is standardized by the RDF Data Access Working Group (DAWG) of the World Wide Web Consortium, and is considered a component of the semantic web. •  Initially released as a Candidate Recommendation in April 2006, but returned to Working Draft status in October 2006, due to two open issues. [2] In June 2007, SPARQL advanced to Candidate Recommendation once again. [3] On 12th November 2007 the status of SPARQL changed into Proposed Recommendation. [4] On 15th January 2008, SPARQL became an official W3C Recommendation. [5]page 39 Semantic Web in Action
  40. 40. SPARQL: SPARQL Protocol and RDF Query Language ¢  SPARQL = •  A Query Language •  A Result Form •  An Access Protocolpage 40 Semantic Web in Action
  41. 41. SPARQL: SPARQL Protocol and RDF Query Language ¢  The Query Language: query forms •  « Select » clause returns all or subset of the variables bound in a query pattern match •  « Construct » returns an RDF graph constructed by substituting variables in a set of triple templates •  « Ask » returns a boolean indicating whether a query pattern matches •  « Describe » returns an RDF graph that describe the resources foundpage 41 Semantic Web in Action
  42. 42. SPARQL: SPARQL Protocol and RDF Query Language ¢  «Select » equivalent to « SQL Select » returns a regular table Select … From … Identify data sources to query Where { … } The triple/graph pattern to be matched against the triple/graphs of RDF A conjunction of triples ¢  PREFIX to declare the schema used in the querypage 42 Semantic Web in Action
  43. 43. SPARQL: SPARQL Protocol and RDF Query Language ¢  PREFIX foaf: <http://xmlns.com/foaf/0.1/> SELECT ?name FROM <http://example.org/foaf/aliceFoaf> WHERE { ?x foaf:name ?name } Result: name « Alice »page 43 Semantic Web in Action
  44. 44. SPARQL: SPARQL Protocol and RDF Query Language ¢  PREFIX foaf: <http://xmlns.com/foaf/0.1/> PREFIX : <http://dbpedia.org/resource/> PREFIX dbpedia2: <http://dbpedia.org/property/> PREFIX dbpedia: <http://dbpedia.org/> SELECT distinct ?name ?birth ?person FROM http://dbpedia.org/ WHERE ¢  { ?person dbpedia2:birthPlace <http://dbpedia.org/resource/Berlin>. ?person dbpedia2:birth ?birth . ?person foaf:name ?name . }page 44 Semantic Web in Action
  45. 45. SPARQL: SPARQL Protocol and RDF Query Language¢  SPARQL results:¢  namebirthperson« ":Dru_Berrymore/birth/birth_date_and_age :Dru_Berrymore "Dru Berrymore"@de:Dru_Berrymore/birth/birth_date_and_age :Dru_Berrymore "Walter Benjamin"@de:Berlin :Walter_Benjamin "Walter Benjamin"@de:Germany :Walter_Benjamin Name Birth Person « Dru Berrymore »page 45 Semantic Web in Action
  46. 46. SPARQL: SPARQL Protocol and RDF Query Language ¢  SELECT distinct ?name ?person FROM <http://dbpedia.org/> WHERE { ?person dbpedia2:birthPlace <http://dbpedia.org/ resource/Berlin> . ?person foaf:name ?name . } ¢  SELECT distinct ?name ?birth ?death ?person FROM <http://dbpedia.org/> WHERE { ?person dbpedia2:birthPlace <http://dbpedia.org/ resource/Berlin> . ?person dbpedia2:birth ?birth . ?person foaf:name ?name . ?person dbpedia2:death ?death. }page 46 Semantic Web in Action
  47. 47. SPARQL: SPARQL Protocol and RDF Query Language ¢  A constraint, expressed by the keyword “FILTER”, is a restriction on solutions over the whole group in which the filter appears ¢  PREFIX dc: <http://purl.org/dc/elements/1.1/> PREFIX ns: <http://example.org/ns#> SELECT ?title ?price WHERE { ?x ns:price ?price . FILTER (?price < 30.5) ?x dc:title ?title . }page 47 Semantic Web in Action
  48. 48. SPARQL: SPARQL Protocol and RDF Query Language ¢  “regex” matches only plain literals with no language tag ¢  { ?x foaf:name ?name . ?x foaf:mbox ?mbox . FILTER regex(?name, "Smith") } ¢  PREFIX dc: <http://purl.org/dc/elements/1.1/> SELECT ?title WHERE { ?x dc:title ?title FILTER regex(?title, "web", "i" ) }page 48 Semantic Web in Action
  49. 49. SPARQL: SPARQL Protocol and RDF Query Language ¢  Optional parts of the graph pattern may be specified syntactically with the “OPTIONAL” keyword applied to a graph pattern ¢  SELECT distinct ?name ?birth ?death ?person FROM <http://dbpedia.org/> WHERE { ?person dbpedia2:birthPlace <http:// dbpedia.org/resource/Berlin> . ?person dbpedia2:birth ?birth . ?person foaf:name ?name . OPTIONAL {?person dbpedia2:death ?death} }page 49 Semantic Web in Action
  50. 50. SPARQL: SPARQL Protocol and RDF Query Language ¢  Matching alternative •  Pattern alternatives are syntactically specified with the UNION keyword ¢  SELECT distinct ?name ?birth ?death ?person WHERE { {?person dbpedia2:birthPlace <http://dbpedia.org/resource/Berlin> } UNION {?person dbpedia2:death ?death} ?person foaf:name ?name . ?person dbpedia2:birth ?birth . }page 50 Semantic Web in Action
  51. 51. SPARQL: SPARQL Protocol and RDF Query Language¢  Sequence & Modify •  « Order By » to sort, •  « LIMIT » result number, •  « OFFSET » rank of first result¢  SELECT distinct ?name ?person WHERE { ?person dbpedia2:birthPlace <http://dbpedia.org/resource/Berlin>. ?person foaf:name ?name. } ORDER BY ?name LIMIT 20 OFFSET 20page 51 Semantic Web in Action
  52. 52. SPARQL: SPARQL Protocol and RDF Query Language ¢  « Construct » •  The CONSTRUCT query form returns a single RDF graph specified by a graph template. -  The result is an RDF graph formed by taking each query solution in the solution sequence, substituting for the variables in the graph template, and combining the triples into a single RDF graph by set union. •  Useful for aggregating data from multiple sources and merging it into a local store (from Ingenta)page 52 Semantic Web in Action
  53. 53. SPARQL: SPARQL Protocol and RDF Query Language ¢  PREFIX foaf: <http://xmlns.com/foaf/0.1/> FROM <http://molene.enstb.org/mlearning09/wp- content/plugins/wp-rdfa/foaf.php CONSTRUCT { ?friend a foaf:Person; foaf:name ?name; foaf:homepage ?home.} WHERE { ?person foaf:mbox <mailto:ac@enstb.com>; foaf:knows ?friend. ?friend foaf:name ?name; foaf:homepage ?home.}page 53 Semantic Web in Action
  54. 54. SPARQL: SPARQL Protocol and RDF Query Language ¢  ASK •  Returns a true/false value: test whether or not a query pattern has a solution. •  No information is returned about the possible query solutions, just whether or not a solution exists •  Is there data that looks like this? Do you have any information about that? (from Ingenta) ¢  PREFIX foaf: <http://xmlns.com/foaf/0.1/> ASK WHERE { ?person a foaf:Person; foaf:mbox <mailto:ab@telecom-bretagne>. }page 54 Semantic Web in Action
  55. 55. SPARQL: SPARQL Protocol and RDF Query Language ¢  DESCRIBE •  The DESCRIBE form returns a single result RDF graph containing RDF data about resources. •  CONSTRUCT but with less control -  Tell me about this or things that look like this … but you decide what’s relevant (from Ingenta) ¢  PREFIX foaf: <http://xmlns.com/foaf/0.1/> DESCRIBE ?friend WHERE { ?person foaf:mbox “mailto:ab@telecom-bretagne”; foaf:knows ?friend.}page 55 Semantic Web in Action
  56. 56. SPARQL: SPARQL Protocol and RDF Query Language ¢  Applied uses (from Ingenta) •  DESCRIBE for Prototyping -  DESCRIBE <http://example.org/someResource> -  Quickly assembling Uis, Web APIs •  SELECT for Indexing -  Building an ordering over some data ORDER BY, LIMITpage 56 Semantic Web in Action
  57. 57. SPARQL: SPARQL Protocol and RDF Query Language ¢  Applied uses (from Ingenta) •  CONSTRUCT for transformation and also simple inferencing -  CONSTRUCT could be the XSLT of RDF -  Currently limited by lack of expressions in CONSTRUCT triple templates •  ASK for validation •  ASK – DESCRIBE – CONSTRUCT Pattern: -  Probe endpoint, Grab default view of data, Refine data extraction and/or apply transformationpage 57 Semantic Web in Action
  58. 58. SPARQL: SPARQL Protocol and RDF Query Language ¢  SPARQL Protocol (from F. Gandon, INRIA) •  Sending queries and their results accross the web ¢  Example with HTTP binding •  GET /sparql/?query=<encoded query> HTTP/1.1 Host: www.inria.fr User-agent: my-sparql-client/0.1page 58 Semantic Web in Action
  59. 59. SPARQL: SPARQL Protocol and RDF Query Language ¢  Example with SOAP binding (from F. Gandon) ¢  <?xml version="1.0" encoding="UTF-8"?> <soapenv:Envelope xmlns:soapenv="http://www.w3.org/2003/05/soap-envelope/" xmlns:xsd="http://www.w3.org/2001/XMLSchema" xmlns:xsi="http:// www.w3.org/2001/XMLSchema-instance"> <soapenv:Body> <query-request xmlns="http://www.w3.org/2005/09/sparql- protocol-types/#"> <query> SELECT ?x ?p ?y WHERE {?x ?p ?y} </query> </query-request> </soapenv:Body> </soapenv:Envelope>page 59 Semantic Web in Action
  60. 60. SPARQL: SPARQL Protocol and RDF Query Language ¢  Access to Data on the web •  http://dbpedia.org/snorql/ •  http://dbpedia.org/sparql •  http://demo.openlinksw.com/rdfbrowser2/ •  http://dataviewer.zitgist.com/ •  Etc. ¢  Twinkle : a sparql query tool •  http://www.ldodds.com/projects/twinklepage 60 Semantic Web in Action
  61. 61. SPARQL: SPARQL Protocol and RDF Query Language ¢  Resources •  http://en.wikipedia.org/wiki/SPARQL •  http://www.w3.org/TR/rdf-sparql-query/ •  http://jena.sourceforge.net/ARQ/Tutorial/ •  http://esw.w3.org/topic/SparqlImplementations •  http://arc.semsol.org/home •  http://virtuoso.openlinksw.com/wiki/main/Main/page 61 Semantic Web in Action
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