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GoodRelations Tutorial Part 4
- 1. The Web of Data for E-Commerce in Brief A Hands-on Introduction to the GoodRelations Ontology, RDFa, and Yahoo! SearchMonkey October 25, 2009 Westfields Conference Center near Washington, DC, USA Martin Hepp Universität der Bundeswehr München, Munich, Germany Richard Cyganiak Digital Enterprise Research Institute (DERI), Ireland
- 2. Logistics 08:30-10:30 Overview and Motivation: Why the Web of Data is Now 30’ Quick Review of Prerequisites 15’ The GoodRelations Ontology: E-Commerce on the Web of Data 75’ 10:30-10:45 Coffee Break 10:45-12:30 RDFa: Bridging the Web of Documents with the Web of Data 45’ Expressing GoodRelations in RDFa: A Running Example 30’ GoodRelations – Advanced Topics 30’ 12:30-13:30 Lunch Break 13:30-16:00 Hands-on Exercise: Annotating a Web Shop 60’ Querying the Web of Data for Offerings – SPARQL 15’ Querying the Web of Data – Exercises 15’ 16:00-16:30 Coffee Break 16:30-18:00 Publishing Semantic Web Data: Make Your RDF Available 30’ Yahoo SearchMonkey and Yahoo BOSS 45’ Discussion, Conclusion, Feedback Round 15’ 2
- 3. SPARQL Query Language Endpoint Specification 25.10.2009 3
- 4. SPARQL: Query Language Specification http://www.w3.org/TR/rdf-sparql-query/ 25.10.2009 4
- 5. SPARQL Query Structure # comments PREFIX gr:<http://purl.org/goodrelations/v1#> SELECT ?var1 ?var2 WHERE {?var1 rdf:type gr:Offering. ?var1 gr:validThrough ?var2. FILTER (?date < "2009-05-25T00:00:00Z"^^xsd:dateTime)} 25.10.2009 5
- 6. SPARQL: Matching Literals PREFIX xsd:<http://www.w3.org/2001/XMLSchema#> SELECT ?v WHERE { ?v ?p "abc"^^xsd:datatype } 25.10.2009 6
- 7. SPARQL: Matching Strings PREFIX dc: <http://purl.org/dc/elements/1.1/> SELECT ?title WHERE { ?x dc:title ?title FILTER regex(?title, "^SPARQL") } ^= Starts with 25.10.2009 7
- 8. SPARQL Query # find expired offerings: PREFIX gr:<http://purl.org/ goodrelations/v1#> SELECT ?o, ?date WHERE {?o rdf:type gr:Offering. ?o gr:validThrough ?date. FILTER (?date < "2009-05-25T00:00:00Z"^^xsd:dateTime )} 25.10.2009 8
- 9. SPARQL Query # find label for UPC/EAN "0001067792600“ PREFIX gr:<http://purl.org/goodrelations/ v1#> PREFIX xsd:<http://www.w3.org/2001/ XMLSchema#> SELECT ?uri, ?label WHERE {?uri rdf:type gr:ProductOrServiceModel. ?uri gr:hasEAN_UCC-13 "0001067792600"^^xsd:string. ?uri rdfs:label ?label} 25.10.2009 9
- 10. Quizzes • Why is it important to use the OPTIONAL clause for patterns that cannot be assumed to be found? • What is a Semantic Sitemap? 25.10.2009 10
- 11. Publishing Data on the Semantic Web 25.10.2009 11
- 12. Publishing RDF Data on the Web • Publishing RDF/XML files • RDFa - Embedding RDF in XHTML • dataRSS 25.10.2009 12
- 13. Step 1: Publish File Save the RDF/XML file under the filename • semanticweb.rdf in the root directory of your Web server so that it becomes available as • http://example.org/semanticweb.rdf 25.10.2009 13
- 14. Point to RDF/XML from HTML/XHTML • Add a link element pointing to this file to the header of your main Web page (or other pages, too): <html lang="en"> <head> <title></title> <link rel="meta" type="application/rdf+xml" title="RDF/XML data for ***your company name***" href="http://www.example.org/semanticweb.rdf" /> </head> ... 25.10.2009 14
- 15. Notify Semantic Web Search Engines To do so, simply paste the URI • http://example.org/semanticweb.rdf into the respective fields of the following submission pages: • http://pingthesemanticweb.com/ • http://sindice.com/main/submit • http://swoogle.umbc.edu/index.php? option=com_swoogle_service&service=submit 25.10.2009 15
- 16. Server Configuration • Rewrite – http://example.org/semanticweb to – http://example.org/semanticweb.rdf • Correct media type rdf+xml – The content type (media type) of the file returned must be set correctly to "rdf+xml". 25.10.2009 16
- 17. Web Page Content Negotiation HTML/ XHTML Meta-Data RDF/XML http GET Web ? Server Returns Web Page HTML/ XHTML Meta-Data RDF/XML 25.10.2009 17
- 18. Server Configuration On Appache servers, simply edit the .htaccess file: #Rewrite rule to serve RDF/XML content from the vocabulary URI RewriteRule ^semanticweb$ semanticweb.rdf #Directive to ensure *.rdf files served as appropriate content type #if not present in main apache config AddType application/rdf+xml .rdf 25.10.2009 18
- 19. Publishing RDF/XML Data on MS IIS Platforms • Ionics Isapi Rewrite Filter for IIS 5.0 and IIS 6.0 – http://iirf.codeplex.com/ • Microsoft URL Rewrite Module for IIS 7.0 – http://support.microsoft.com/kb/324064 (Thanks to Christophe Debruyne and Robert Meersman for the hint!) • ModRewrite – http://www.micronovae.com/ModRewrite/ ModRewrite.html (Thanks to Sergio Fernández for the link!) 25.10.2009 19
- 20. Semantic Sitemaps • Efficient means of telling a Semantic Web search engine which RDF files are available http://sw.deri.org/2007/07/sitemapextension/ 25.10.2009 20
- 21. Additional Information • Cool URIs for the Semantic Web, W3C Interest Group Note 03 December 2008 http://www.w3.org/TR/cooluris/ 25.10.2009 21
- 22. RDFa: Bridging the Web of Documents with the Web of Data Martin Hepp 25.10.2009 22
- 23. Learning Goal • Understand the data quality problems that can result from the „naive“ Semantic Web • Understand the RDFa syntax for embedding RDF data into XHTML documents • Be able to express GoodRelations data in RDFa 25.10.2009 23
- 24. Data Redundancy and Data Quality Problems Addresses Addresses Addresses Copy of Copy of Time Addresses Addresses 25.10.2009 24
- 25. Data Redundancy in the Semantic Web Web Page Web Page HTML/ HTML/ XHTML XHTML Meta-Data Meta-Data Time RDF/XML RDF/XML 25.10.2009 25
- 26. Embedding RDF in XHTML • Being able to represent meaning and rendering information in a single document http GET XHTML + Web RDFa Server XHTML + Returns RDFa 25.10.2009 26
- 27. = + XHTML Resource Description Framework in attributes 25.10.2009 27
- 28. What is RDFa? • From the Web of Documents' point-of- view: a set of new (X)HTML attributes to express metadata within (X)HTML • From the Web of Data point-of-view: a serialization format for RDF (such as RDF/ XML, etc.), where the RDF triples are "embedded" into (X)HTML 25.10.2009 28
- 29. Yahoo SearchMonkey Currently considers RDF data only if • submitted via the (proprietary) dataRSS feed format or if • embedded inside XHTML pages via RDFa. http://www.ebusiness-unibw.org/tools/rdf2datarss/ 25.10.2009 29
- 30. RDF in Attributes <h1 property="dc:title">GoodRelations RDFa minimal example</h1> 25.10.2009 30
- 31. Subject – Predicate – Object • @about (URIorSafeCURIE) … for setting the subject of a statement • @typeof (CURIEs) … for setting the type(s) of a resource (syntactic sugar) • @href/@resource (URIorSafeCURIE) … for setting the object of a statement 25.10.2009 31
- 32. Subject – Predicate – Object • @property (CURIEs) … for relating a resource to a literal value, that is, for datatype properties • @rel/@rev (reserved word | CURIE)+ … for relating a resource to another resource, that is, for object properties 25.10.2009 32
- 33. Subject – Predicate – Object • @content (CDATA) … for setting a literal object value • @datatype (CURIE) … for the datatype of a literal object value - if not specified, then the default value is xsd:string 25.10.2009 33
- 34. DOCTYPE <?xml version="1.0" encoding="UTF-8"?> <!DOCTYPE html PUBLIC "-//W3C//DTD XHTML +RDFa 1.0//EN" "http://www.w3.org/MarkUp/ DTD/xhtml-rdfa-1.dtd"> <html xmlns="http://www.w3.org/1999/xhtml" <head profile="http://www.w3.org/1999/xhtml/ vocab"> <title>GoodRelations RDFa minimal example</title> </head> (…) 25.10.2009 34
- 35. Example - Markup • http://www.w3.org/TR/xhtml-rdfa-primer/ alice-example.html • Install Operator on FF • Debug page 25.10.2009 35
- 36. RDFa: Simplistic Usage Reusing existing text and values at their original position 25.10.2009 36
- 37. RDFa: Snippet Style Embedding additional meta-data in the same document, but detached from the human-readable content 25.10.2009 37
- 38. RDF2RDFa Tool: Snippets http://www.ebusiness-unibw.org/tools/rdf2rdfa/ 25.10.2009 38
- 39. Quizzes • Why is RDFa important to simplify the creation of Semantic Web content? • How does RDFa contribute to a better quality of Semantic Web data? • What is the main principle of RDFa? • Name the key elements and give a simple example of using RDFa. 25.10.2009 39
- 40. Hands-on Exercises: Creating, Publishing, and Querying Martin Hepp 25.10.2009 40
- 41. Step-by-Step (1) • Data Sources • Data Delivery Options – Form-based data entry – RDFa: Embedding meta- – RDBMS data in XHTML – XML, e.g. BMEcat – RDF/XML: Extra file – CSV – dataRSS: Yahoo feed – Google CSV, RSS 1.0, format RSS 2.0 • Amount of Detail and Data Model – What shall be included? – How shall the type of products be represented? 41
- 42. Step-by-Step (2) • Update Mechanism & Data Management – PHP on demand – Script-based data dump • Publishing the Data – Server configuration – Notifying Semantic Web crawlers, Yahoo, … – Semantic Sitemaps • Applications 42
- 46. Google Product Feed Converter http://tr.im/sLcX 25.10.2009 46
- 47. BMEcat2GoodRelations • Converts complete catalogs from the popular BMEcat XML Schema into GoodRelations http://www.ebusiness-unibw.org/tools/bmecat2goodrelations/ 25.10.2009 47
- 48. GoodRelations in MediaWiki http://www.ebusiness-unibw.org/wiki/RDFaInMediaWiki 25.10.2009 48
- 49. GoodRelations in Oxid eSales • Popular shop software • Free recipe for adding GoodRelations, developed by Daniel Bingel http://www.ebusiness-unibw.org/wiki/GoodRelations4Oxid 25.10.2009 49
- 52. Task 1 • Use the GoodRelations Annotator to create a description for your business or a business that you know. 25.10.2009 52
- 53. Task 2 • Using Turtle & GoodRelations, describe the following business. – Miller Tax Consulting Inc., having two stores, selling office supplies and tax consultancy • Convert the Turtle to RDF/XML and validate it. • Convert the RDF/XML to RDFa using RDF2RDFa and paste it into a page of your choice. 25.10.2009 53
- 54. Task 3 • Query the SPARQL endpoint at http://loc.openlinksw.com/sparql for the product properties and values for the product with the EAN/UPC code 8714574993836. 25.10.2009 54
- 55. Thank you. 25.10.2009 55