The second edition of this best-seller is revised and updated. It delivers a reader-friendly explanation of the relational model and its importance to database designers and builders. Clear explanations make use of examples rather than equations, and show how an understanding of the relational model can lead to making a database faster and flexible. Topics covered include: nulls, primary and foreign keys, joins, relationships, domains, indexing, and many others. The authors manage to shed light on this tricky subject with substance and style.