The purpose of this book is to help you build relational databases and get valuable information out of them by using SQL. SQL is the international standard language used around the world to create and maintain relational databases. This edition covers the latest version of the standard, SQL:2003, as augmented in 2005 with a thorough treatment of the use of XML with SQL.
This book doesn’t tell you how to design a database (I do that in Database Development For Dummies, also published by Wiley Publishing, Inc.). Here I assume that you or somebody else has already created a valid design. I then illustrate how you implement that design by using SQL. If you suspect that you don’t have a good database design, by all means, fix your design before you try to build the database. The earlier you detect and correct problems in a development project, the cheaper the corrections will be.