Content area
Full Text
Learning XML Schema won't be easy, but don't let that stop you
THE GOOD NEWS is that Office 11 supports XML Schema. The bad news is that XML Schema has been described even by XML experts as "confusing," "impenetrable," "fuzzy; and "as user-friendly as a stick in the eye." A successor to the SGML/XML DTD (Standard Generalized Markup Language/XML document type definition), XML Schema is a language for writing rules that constrain the kinds of elements that can appear in documents and the ways in which they can be sequenced, grouped, and nested.
XML Schema is still a relatively new specification. The W3C Recommendation for XML Schema was published in May 2001. XML parsers that support XML Schema haven't done so for very long, and there is not yet much experience using it. Most people who are adept at defining document structure learned how to do so by writing DTDs. Some of the allergic reaction to XML Schema can, therefore, be chalked up to normal reluctance to learn new skills.
Of course, it's hard to work up a lot of nostalgia for the DTD legacy. Adjectives such as "confusing" and "impenetrable" were also flung at SGML DTD. Back in the day, more than a few large document management projects - like too many modern ERP systems - produced a lot of sound and fury, signifying nothing. The fact is that, although sets of documents do exhibit databaselike properties that we can usefully formalize and exploit, this kind of information management is still in its infancy.
Boeing, one notable exception, has always understood that documentation is integral to its business. The company likes to joke that ajet is "five million parts flying in formation" The documents that describe that inventory are themselves part of the inventory, and are engineered accordingly. Applying that same discipline to routine business documents such as resumes, expense reports, and purchase orders,...