Introduction to RDFa

RDFa

A proposed semantic data format – not yet a standard

First proposed in 2004

Web page Joe Semantic's personal information I work as a programmer at MegaCorp - you can contact me at [email_address] , or by phone at (101)010-1010.

HTML source <html> <head> <title>Joe Programmer's contact info</title> <base href="http://joeprogrammer.com/contact-info.html" /> </head> <body> <h1>Joe Semantic's personal information</h1> <p>I work as a programmer at <a href="http://megacorp.com">MegaCorp</a> - you can contact me at <a href="mailto:js@megacorp.com">js@megacorp.com</a>, or by phone at (101)010-1010.</p> </body> </html>

RDF page <?xml version="1.0" encoding="UTF-8"?> <rdf:RDF xmlns:contact="http://www.w3.org/2001/vcard-rdf/3.0#" > <rdf:Description rdf:about= "http://joesemantic.com/contact-info.html" > <contact:title xml:lang="en">programmer</contact:title> <contact:org rdf:resource="http://megacorp.com"/> <contact:email rdf:resource="js@megacorp.com"/> <contact:tel xml:lang="en"> (101)010-1010 </contact:tel> </rdf:Description> </rdf:RDF>

Why not combine the two?

<html xmlns:contact="http://www.w3.org/2001/vcard-rdf/3.0#" > <head> <title>Joe Semantic's personal information</title> <base href="http://joesemantic.com/contact-info.html" /> </head> <body> <h1>Joe Semantic's personal information</h1> <p>I work as a <span property=”contact:title”>programmer</span> at <a href="http://megacorp.com" rel="contact:org">MegaCorp</a> - you can contact me at <a rel="contact:email" href="mailto:js@megacorp.com">js@megacorp.com</a> , or by phone at <span property=”contact:tel”>(101)010-1010</span> .</p> </body> </html>

Three main keywords in RDFa <a href=” object ” rel =” predicate ”>...</a> ...defines a linked triple <span property =” predicate ”> object </span> ...defines an unlinked triple <span about =” subject ”>...</span> ...creates a temporary subject for triples

Creating temporary subjects ... I'm currently reading <span about=”urn:ISBN:0-596-00027-8”> <span property="dc:title">Programming Perl</span> by <span property="dc:creator">Larry Wall</span> </span> . ...