Database Systems

Fundamentals of Database Systems by Ramez Elmasri Navathe
Fundamentals of Database Systems is a leading example of a database text that approaches the subject from the technical, rather than the business perspective. 
This is an outstanding, up-to-date database book, appropriate for both undergraduate and graduate courses. It contains good examples, and clearly describes how to design good, operable databases as well as retrieve and manipulate data from an existing database.


Introduction to Database Systems, An (8th Edition) (Introduction to Database Systems) by C.J. Date
This is an extraordinarily academic book. In his preface, C.J. Date goes so far as to lament having to use Structured Query Language (SQL) in some of his examples because it's "so far from being a true embodiment of relational principles." What's more, he writes in a very academic style, peppering his heavily footnoted prose with mathematical expressions and words like relevar and tuple. The academic style and highbrow language isn't a bad thing, since this book deals with complicated, largely abstract phenomena in depth.


Database Management Systems by Raghu Ramakrishnan, Johannes Gehrke
"Database Management Systems" provides comprehensive and up-to-date coverage of the fundamentals of database systems. Coherent explanations and practical examples have made this one of the leading texts in the field. The third edition continues in this tradition, enhancing it with more practical material. The new edition has been reorganized to allow more flexibility in the way the course is taught. Now, instructors can easily choose whether they would like to teach a course which emphasizes database application development or a course that emphasizes database systems issues. 

Database in Depth: Relational Theory for Practioners by C. J. Date
Database in Depth will appeal not only to database developers and designers, but also to a diverse field of professionals and academics, including database administrators (DBAs), information modelers, database consultants, and more. Virtually everyone who deals with relational databases should have at least a passing understanding of the fundamentals of working with relational models.
This book sheds light on the principles behind the relational model, which is fundamental to all database-backed applications--and, consequently, most of the work that goes on in the computing world today.