If you are really interested in making a career out of databases, then this is a book you got to read. An analogy that comes to mind is "You got to have a strong foundation to build a sky craper". This is exactly what this book is. It helps you build a strong foundation.
I got hold of this book when I was in my 4th Semester of my BS in computer science (1994 - 2nd Edition of this book) to clear my Database concepts exam. Ever since, whenever I feel I might not have understood some concept, I go back to this book.
One thing you got to understand is, its not a book that you can just read through and tell people that you have understood the concepts. You need to work the book.
IBM DB2 UDB Certified Specialist.
Avoid it, unless you want to waste you time with a book that makes learning 10 times slower than with a good one.