Database in Depth: Relational Model for Practitioners [ペーパーバック]

Over the last week or so, I've been reading C. J. Date's book Database In Depth - Relational Theory for Practitioners (O'Reilly). While it's a well-done title, it's the type of book I have a hard time reading...

Contents:

Introduction; Relations Versus Types; Tuples And Relations; Relation Variables; Relational Algebra; Integrity Constraints; Database Design Theory; What Is The Relational Model?; A Little Bit Of Logic; Suggestions For Further Reading; Index

C. J. Date, along with E. F. Codd (the acknowledged "father" of relational database theory), are probably the two most influential individuals in this field. Much of what we know and practice in today's RDBMS packages all goes back to the work these two have done. Rather than write a textbook style discussion of the finer points of database theory, Date has used this book to update some of his thinking and to consolidate a number of his talks and writings of late. For serious students of relational database concepts, I'd consider this the latest "must read" to keep up with current thinking by one of the masters.

Having said that, I had a hard time slogging through the material. I tend to gravitate to technical reading material that is practical and understandable. Debates over finer points of arcane minutia will cause me to zone out quickly. Unfortunately, I felt that way through a lot of this book. There is a lot of solid technical material here, and it's definitely geared towards serious readers. Date doesn't have a lot of kind words to say about how database vendors have implemented the relational model, nor does he feel SQL is a good thing. I, on the other hand, figure the packages are what they are, and you had better learn to use them to create the systems needed by your customers. That's probably why I'm a developer and not a system architect. Reading a number of pages on why Date and Codd disagree on whether nulls are valid or allowed doesn't do much for me. They're there, you need to understand them, and then you need to move on. Another hard part for me was the heavy emphasis on mathematical proofs and such. Since I don't have that type of background, I'm quickly lost...

Even though I wasn't completely enamored with the book, I still think it is a good title. For the right reader, this will be material that they will benefit from. For the average person who got training on Oracle or DB2 and understand basic relational database theory, this may be a bit more difficult to get through...

This book is more or less exactly what it claims to be: a solid theoretical grounding in the relational model targeted at working software developers and database programmers. It combines concise explanations with explorations of pragmatic concerns, and includes genuinely useful exercises at the end of each chapter. If you're somebody who understands things best when you understand why the system is doing what it does, you'll find this book invaluable in sorting through questions like, "Why should I normalize the schema? Why are NULLs bad? What's a quota query?"

Speaking as someone who really enjoys abstract theoretical discussions of programming concepts, my only significant fault with the book was that occasionally Date's use of language was a little more informal than I would have liked; I would have liked a slightly more rigorous explanation of the links between the predicate calculus and set theory and the relational model, and could have used more mathematical notation. In addition, sometimes Date is... if not disingenuous, a little quick in glossing over the changes he has made to the relational model over the years (he and E. F. Codd, the originator of the relational model, diverged in their thinking a bit over the years).

One caveat: this book is not a cookbook or a how-to guide. It works from first principles outwards, and as such isn't exactly filled with immediately useful code snippets. In fact, as much as possible Date uses his own relational data language, Tutorial D, instead of SQL. He does have good reasons for disliking SQL as a pedagogical tool (or much of anything else), which he explains in depth throughout the text, but people who work best with directly applicable code they can pick up and apply to their own problems will find this book frustrating.

Overall, though, this is a quick, dense read and will do an amazing amount to clarify your thinking about how database systems work and what they ought to be.

Relational atabases are fundamental to today's IT operations. They underpin virtually all transactional and content management systems. Knowing how to work with relational databases is a critical tool in every IT practitioner's kit.

However, many learn how to use RDBMs via practical, on-the-job experience, or perhaps through a RDBMs vendor class, without understanding the underlying theory. Just as many programmers who work with classes and objects could become more proficient with a deeper grasp of object theory, the same is true for database designers, DBAs, and software engineers responsible for data interface layers.

This book provides a great knowledge base of the general theory of RDBMs in an thorough, well-organized and easy to read format - which is not an easy combo to carry off.

Database in Depth is particularly useful if your exposure to RDBMs has been through the lens of a particular vendor. It's easy to get confused between functionality and implementation; this book helps clarify the difference.

If you feel like you use databases without really understanding what does on under the hood, read this book.