All of today’s mainstream database products support the SQL language, and relational theory is what SQL is supposed to be based on. But are those products truly relational? Sadly, the answer is no. This book shows you what a real relational product would be like, and how and why it would be so much better than what’s currently available. With this unique book, you
Christopher J. Date (born 1941) is an independent author, lecturer, researcher, and consultant, specializing in relational database theory. —from wikipedia
I feel like this book was mostly a hot mess, except for the chapter on transactions. I was already familiar with most of the concepts in the book, but was looking for another perspective and things I may need to unlearn or rethink. Date's writing style reminds me of a college professor who has a ton of great information for a lecture, however, gets easily sidetracked and goes off on distracting tangets. I would not be surprised if this book was actually transcribed from a lecture or seminar series.
TLDR: good information, but presentation is confusing and all over the place.