Paul Grosso

This article compares and contrasts the broad functionality of XML Schemas (whose approval by the World Wide Web Consortium is imminent) with that of document type definitions, currently part of the XML 1.0 Recommendation. Let's begin with some background to describe the need for schemas and DTDs. XML holds out the promise of sharing all kinds of information effortlessly, with automated and loss-free exchanges among disparate information systems. XML defines how to mark up content to give it both structure and additional meta-information. This increases the worth of the data many times by allowing a wide variety of applications to make greater use of the content. However, as with any structured information exchange, all parties must adhere to a mutual agreement on the syntax and semantics of the data or chaos will ensue. The XML 1.0 specification fulfills the need for ... (more)