Jan L. Harrington - Relational Database Design and Implementation

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ISBN: 978-0-12-804399-8

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One of my favorite opening lines for the database courses I taught during my 32 years as a college professor was: Probably the most misunderstood term in all of business computing is database , followed closely by the word relational . At that point, some students would look a bit smug, because they were absolutely, positively sure that they knew what a database was and that they also knew what is meant for a database to be relational. Unfortunately, the popular press, with the help of some PC software developers, long ago distorted the meaning of both these terms, which led many small business owners to think that designing a database was a task that could be left to a clerical worker who had taken a few days training in using database software.

At the other end of the spectrum, we found large businesses that had large data management systems that they called databases, but depending on the software being used and the logical structuring of the data, may or may not have been. Even 45 years later, the switch to the relational data model continues to cause problems for companies with significant investments in prerelational legacy systems.

There are data models older than the relational data model and even a couple of new ones (object-oriented and NoSQL) that are postrelational. Nonetheless, the vast majority of existing, redesigned, and new database systems are based on the relational data model, primarily because it handles the structured data that form the backbone of most organizational operations. Thats why this book, beginning with the first edition, has focused on relational design, and why it continues to do so.

This book is intended for anyone who has been given the responsibility for designing or maintaining a relational database (or whose college degree requirements include a database course). It will teach you how to look at the environment your database serves and to tailor the design of the database to that environment. It will also teach you ways of designing the database so that it provides accurate and consistent data, avoiding the problems that are common to poorly designed databases. In addition, you will learn about design compromises that you might choose to make in the interest of database application performance and the consequences of making such choices.

For the first time, this edition also includes coverage of using SQL, the international standard for a relational database query language. What you have in your hands is therefore a complete treatment of the relational database environment. There is also an appendix on prerelational data models and two chapters on the postrelational data models.