Content-centric XML: Where We've Been, Where We're Going in 2003

摘要

As EContent readers, you likely develop, manage or deliver content. In doing so, increasingly you encounter the three-letter acronym XML, short for "eXtensible Markup Language." This is true whether your content is only text, graphics, streaming media, voice, or any combination thereof. Read resumes today and you're likely to see claims of XML skills, but when you press candidates to learn what they mean, most inadvertently cite "data-centric" XML experience―the use of XML to interchange information between systems, often for ecommerce or Web applications. One way to determine if candidates are familiar with XML for content is to ask how they viewed or developed XML models. If you get a blank stare or a response like "Notepad," the candidate is probably familiar only with data-centric XML, if that. The use of data-centric XML has in fact taken the software world by storm but is only one of the originally intended uses of XML. Content-centric XML―or simply "XML" in the rest of this column―is likely to be of more interest to you, and such XML requires conformance to a document model expressed as a document type definition (DTD) or, increasingly, as an XML schema. Schemas can express and enforce far richer models, like "date," which DTDs express only as text.