Chapter 18. Resource Description Framework and Channel Definition Format

This chapter is about two XML applications that work with metadata. Metadata is data that describes data, and the applications I'm going to take a look at are Resource Description Framework (RDF) and Channel Definition Format (CDF).

As you can gather from its name, RDF is a language that lets you describe resources. Although it's typically used to describe Web documents and sites, you can also use it to describe CD collections, books in a library, a collection of antique pen knives, and more. It's a general-purpose XML application that is helping to standardize the way people handle data on the Internet. Some consistent way of working with vast amounts of data on the Internet is sorely needed, and RDF is one possible solution. You may recall our discussion of canonical XML, which puts XML documents into a format that may easily be compared—RDF is actually stored in documents separate from the resources it describes, and it provides a standard description language.