Database Design and Relational Theory

Chapter 1. Preliminaries

(On being asked what jazz is:)

Man, if you gotta ask, you’ll never know

—Louis Armstrong (attrib.)

This book has as subtitle Normal Forms and All That Jazz. Clearly some explanation is needed! First of all, of course, I’m talking about design theory, and everybody knows normal forms are a major component of that theory; hence the first part of my subtitle. But there’s more to the theory than just normal forms, and that fact accounts for that subtitle’s second part. Third, it’s unfortunately the case that—from the practitioner’s point of view, at any rate—design theory is riddled with terms and concepts that seem to be difficult to understand and don’t seem to have much to do with design as actually done in practice. That’s why I framed the latter part of my subtitle in colloquial (not to say slangy) terms; I wanted to convey the idea, or impression, that although we’d necessarily be dealing with “difficult” material on occasion, the treatment of that material would be as undaunting and unintimidating as I could make it. But whether I’ve succeeded in that aim is for you to judge, of course.

I’d also like to say a little more on the question of whether design theory has anything to do with design as done in practice. Let me be clear: Nobody could, or should, claim that designing databases is easy. But a sound knowledge of theory can only help. In fact, if you want to do design properly—if you want to build databases that are as robust, flexible, and accurate as ...