SQL and Relational Theory, 2nd Edition

Prerequisites

I assume you’re a database practitioner and therefore reasonably familiar with SQL already. To be specific, I assume you have a working knowledge of either the SQL standard or (perhaps more likely in practice) at least one SQL product. However, I don’t assume you have a deep knowledge of relational theory as such (though I do hope you understand that the relational model is a good thing in general, and adherence to it wherever possible is a desirable goal). In order to avoid misunderstandings, therefore, I’ll be describing various features of the relational model in detail, as well as showing how to use SQL to conform to those features. But what I won’t do is attempt to justify all of those features; rather, I’ll assume you’re sufficiently experienced in database matters to understand why, e.g., the notion of a key makes sense, or why you sometimes need to do a join, or why many to many relationships need to be supported. (If I were to include such justifications, this would be a very different book—quite apart from anything else, it would be much bigger than it already is—and in any case, that book has already been written.)

I’ve said I expect you to be reasonably familiar with SQL. However, I should add that I’ll be explaining certain aspects of SQL in detail anyway—especially aspects that might be encountered less frequently in practice. (The SQL notion of possibly nondeterministic expressions is a case in point here. See Chapter 12.)

Database in Depth

This book is ...