Database in Depth

Chapter One. Introduction

Professionals in any discipline need to know the foundations of their field. So if you're a database professional, you need to know the relational model, because that model is the foundation (or a huge part of the foundation, anyway) of the database field in particular. Now, every course in database management, be it academic or commercial, does at least pay lip service to the idea of teaching the relational model—but most of that teaching seems to be done very badly, if results are anything to go by. The relational model certainly isn't very well or very widely understood in the database community at large. Here are some possible reasons for this state of affairs:

• The model is taught in a vacuum. That is, for beginners at least, it's hard to see the relevance of the material, or it's hard to understand the problems it's meant to solve, or both.

• The instructors themselves don't fully understand or appreciate the significance of the material.

• (Most likely in practice.) The model as such isn't taught at all—the SQL language or some specific dialect of that language, such as the Oracle dialect, is taught instead.

So this book is aimed at database professionals, especially commercial database practitioners, who have had some exposure to the relational model but don't know as much about it as they ought to. It's definitely not meant for beginners; however, it isn't a refresher course, either. To be more specific: I'm sure you know something about SQL, but—and I ...