RDF/XML is a format for representing data in RDF, which is a model for structuring metadata. RDF/XML serializes RDF graphs into XML documents so they can be processed by computers. Properties and values in RDF are expressed as elements and attributes in RDF/XML. While RDF/XML allows RDF data to be expressed in XML, it is not very human-readable and other formats like Turtle and JSON may be better for processing by machines and developers.

1. RDF/XMLA brief introductionAlison Hunt March 26, 2011for LIS469 XML

2. RDF/XML is a data formatIt represents information for a data model called RDF

3. RDFResource Description Frameworkis a data modelIt structures metadata forthe Semantic Web andthe RDA content standard(resource description and access)

4. RDFdescribes a resourceLIS469 Class Blog

5. A resource has propertiescreatorlanguageLIS469 Class Blogformatsubject

6. Properties have valuescreatorlanguageLIS469 Class Blogformatsubject

7. RDFdescriptions make statementsThe LIS469 class blog was created by Aaron Rubinstein.The LIS469 class blog is written in English.The LIS469 class blog is formatted as text/HTML.The LIS469 class blog is about the subject of XML.

8. RDFstatements are triplesResourceSubjectLIS469 class blogLIS469 class blogLIS469 class blogLIS469 class blogPropertyPredicateCreatorLanguageFormatSubjectValueObjectAaron RubinsteinEnglishText/HTMLXML

9. RDF statements link two things in one direction.NodeLIS469 class blogLIS469 class blogLIS469 class blogLIS469 class blogArcCreatorLanguageFormatSubjectNodeAaron RubinsteinEnglishText/HTMLXML

10. RDF statements link two things in one direction.Properties may have multiple values.RDF has several ways to model this:blank nodes, bags, collections, etc.However, the end result will be a set of triples which link the subject with each value.

11. RDF statements require URIs that have meaning for computer applicationsResourceMust be a URI<http://lis469.wordpress.com/><http://lis469.wordpress.com/><http://lis469.wordpress.com/><http://lis469.wordpress.com/>Here, the blog URL replaces its name

12. RDF ShinesBy using URIs, RDF can describe things that cannot be located or retrieved on the web.People, institutions, cars, concepts…anything.FRBR works, expressions or manifestationsTiger Lilycollective amnesia

13. RDF statements require URIs for propertiesResourceMust be a URI<http://lis469.wordpress.com/><http://lis469.wordpress.com/><http://lis469.wordpress.com/><http://lis469.wordpress.com/>PropertyMust be a URI<http://purl.org/dc/elements/1.1/creator><http://purl.org/dc/elements/1.1/language><http://purl.org/dc/elements/1.1/format><http://purl.org/dc/elements/1.1/subject>Here, Dublin Core URIs are used for the property

14. Values can be URIs or literal strings of charactersResourceMust be a URI<http://lis469.wordpress.com/><http://lis469.wordpress.com/><http://lis469.wordpress.com/><http://lis469.wordpress.com/>PropertyMust be a URI<http://purl.org/dc/elements/1.1/creator><http://purl.org/dc/elements/1.1/language><http://purl.org/dc/elements/1.1/format><http://purl.org/dc/elements/1.1/subject>ValueCan be URI or literalAaron RubinsteinEnglishText/html<http://id.loc.gov/authorities/sh97007825#concept>Here, XML is identified by a URI from Library of Congress Subject Headings

15. RDF graph with URIsNote:RDF graphs showliterals in a boxURIs in an ovalWe are using a URI as the value of the subject property.So the graph changes from box to oval.This actually indicates a really significant change…<http://purl.org/dc/elements/1.1/creator><http://purl.org/dc/elements/1.1/language><http://lis469.wordpress.com/><http://purl.org/dc/elements/1.1/format><http://purl.org/dc/elements/1.1/subject>

16. A value with a URI can be the subject of other statements<http://purl.org/dc/elements/1.1/creator><http://purl.org/dc/elements/1.1/language><http://purl.org/dc/elements/1.1/format><http://purl.org/dc/elements/1.1/subject>Library ofCongress<http://purl.org/dc/elements/1.1/creator>

17. RDF links stuff!

18. RDF shinesIt is easy to work across different data sources, types and formats.RDF can link things by tapping massive databases of RDF statements called "triplestores."There are more than 27 billion triples stored now.

19. RDF/XML is a data format001111000010100010000100010010001111000000000011110000000111111111100000000000111111111110000000000011XML document serializes the RDF graph so it can beprocessed by computersfor storage and transmission

20. RDF expressed as XMLRDFXMLClass BlogCreator Aaron RubinsteinLanguage EnglishFormat Text-HTMLSubject XML URIThe XML format is closed; it will not link like the RDF graph does.

21. Starting the RDF/XML fileRDFRDF is the root elementThe rdf: prefix is from the rdf namespaceWe are also using Dublin Core elementsXML<?xml version="1.0"?><rdf:RDFxmlns:rdf=http://www.w3.org/1999/02/22-rdf-syntax-ns#xmlns:dc=http://purl.org/dc/elements/1.1/>

22. Where is the resource named?RDFEach resource being described is tagged with the RDF element <description>The about attribute spells out the URIOf the resource that is the subject of the RDF statementXML<?xml version="1.0"?><rdf:RDFxmlns:rdf=http://www.w3.org/1999/02/22-rdf-syntax-ns#xmlns:dc=http://purl.org/dc/elements/1.1/><rdf:DescriptionRdf:about="http://lis469.wordpress.com/">

23. Properties and values?RDFProperties become child elements of Description.They appear as tags.Literal RDF values become the value of those child elements, between opening and closing tags.When RDF values are expressed as URIs, they become an attribute, called "resource," of the child element.XML<?xml version="1.0"?><rdf:RDFxmlns:rdf=http://www.w3.org/1999/02/22-rdf-syntax-ns#xmlns:dc=http://purl.org/dc/elements/1.1/><rdf:DescriptionRdf:about="http://lis469.wordpress.com/"><dc:creator>Aaron Rubinstein</dc:creator><dc:language>English</dc:language><dc:format>text/HTML</dc:format><dc:subjectrdf:resource=" http://id.loc.gov/authorities/sh97007825#concept "/></rdf:Description></rdf:RDF>

24. But properties should be URIs!Namespace declarations generate full URIs for each propertydc: is equivalent to http://purl.org/dc/elements/1.1/<dc:format>text/HTML</dc:format>is processed as<http://purl.org/dc/elements/1.1/ format> text/HTML </ <http://purl.org/dc/elements/1.1/ format>

25. RDF expressed as XMLRDFXML<?xml version="1.0"?><rdf:RDFxmlns:rdf=http://www.w3.org/1999/02/22-rdf-syntax-ns#xmlns:dc=http://purl.org/dc/elements/1.1/><rdf:DescriptionRdf:about="http://lis469.wordpress.com/"><dc:creator>Aaron Rubinstein</dc:creator><dc:language>English</dc:language><dc:format>text/HTML</dc:format><dc:subjectrdf:resource=" http://id.loc.gov/authorities/sh97007825#concept "/></rdf:Description></rdf:RDF>

26. RDF/XML is not the only choicePROSRDF/XML is the syntax primarily used by the W3C from the startIt plays well with the family of XML technologies.XML uses namespaces and can tag (i.e. express RDF properties) with ultimate flexibility.CONSRDF/XML files are hard for people to read.Namespaces don't always behave the way we expectMost of the developers who have to actually generate linked data find RDF/XML clunky RDF/XML obscures triples

27. Other RDF data formats areRDFaEmbeds RDF metadata in html. Part of Drupal7.TURTLEVery easy for people to read. Preserves RDF triples.JSONSupported by major web applications like JavaScript,so easy to process and familiar to developer community.

28. You should knowW3C is overhauling its RDF recommendationshttp://www.w3.org/2011/01/rdf-wg-charterYou can create your own personal URIhttp://www.foaf-project.org/For a great overview, skim the new e-bookLinked Data: Evolving the Web into a Global Data Spacehttp://linkeddatabook.com/editions/1.0DBPedia is the hub of RDF-linked datahttp://dbpedia.org/About

29. The Linked WorldLinking Open Data cloud diagram, by Richard Cyganiak and AnjaJentzsch. http://lod-cloud.net/