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Preface to the First Editionxiii
theoretical, it can’t be practical. But the truth is that theory (at least, relational theory, which is what I’m talking about here) is most definitely very practical indeed. The purpose of that theory is not just theory for its own sake; the purpose of that theory is to allow us to build systems that are 100 percent practical. Every detail of the theory is there for solid practical reasons. As Stéphane Faroult, a reviewer of the earlier book, wrote: “When you have a bit of practice, you realize there’s no way to avoid having to know the theory.” What’s more, that theory is not only practical, it’s fundamental, straightforward, simple, useful, and it can be fun (as I hope to demonstrate in the course of this book).
Fourth, please note that I use the term SQL throughout the book to mean the standard version of that language exclusively, not some proprietary dialect, barring explicit statements to the contrary. In particular, I follow the standard in assuming the pronunciation “ess cue ell,” not “sequel” (though this latter is common in the field), thereby saying things like an SQL table, not a SQL table.
Fifth, the book is meant to be read in sequence, pretty much, except as noted here and there in the text itself (most of the chapters do rely to some extent on material covered in earlier ones, so you shouldn’t jump around too much). Also, each chapter includes a set of exercises. You don’t have to do those exercises, of course, but I think it’s a good idea to have a go at some of them at least. Answers, often giving more information about the subject at hand, are given in Appendix F.
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