How to Read This Book | Database Design for Mere Mortals: A Hands-On Guide to Relational Database Design

The Purpose of This Book

In general terms, there are three phases to the overall database-development process.

Logical design: The first phase involves determining and defining tables and their fields, establishing primary and foreign keys, establishing table relationships, and determining and establishing the various levels of data integrity.
Physical implementation: The second phase entails creating the tables, establishing key fields and table relationships, and using the proper tools to implement the various levels of data integrity.
Application development : The third phase involves creating an application that allows a single user or group of users to interact with the data stored in the database. The application-development phase itself can be divided into separate processes, such as determining end- user tasks and their appropriate sequences, determining information requirements for report output, and creating a menu system for navigating the application.

You should always go through the logical design first and execute it as completely as possible. After you've created a sound structure, you can then implement it within any database software you choose. As you begin the implementation phase, you may find that you need to modify the database structure based on the pros and cons or strengths and weaknesses of the database software you've chosen . You may even decide to make structural modifications to enhance data-processing performance. Performing the logical design first ensures that you make conscious, methodical, clear, and informed decisions concerning the structure of your database. As a result, you help minimize the potential number of further structural modifications you might need to make during the physical-implementation and application-development phases.

This book deals with only the logical-design phase of the overall development process, and the book's main purpose is to explain the process of relational database design without using the advanced, orthodox methodologies found in an overwhelming majority of database-design books. I've taken care to avoid the complexities of these methodologies by presenting a relatively straightforward, commonsense approach to the design process. I also use a simple and straightforward data-modeling method as a supplement to this approach, and present the entire process as clearly as possible and with a minimum of technical jargon.

There are many database-design books out on the market that include chapters on implementing the database within a specific database product, and some books even seem to meld the design and implementation phases together. (I've never particularly agreed with the idea of combining these phases, and I've always maintained that a database developer should perform the logical-design and implementation phases separately to ensure maximum focus, effectiveness, and efficiency.) The main drawback that I've encountered with these types of books is that it can be difficult for a reader to obtain any useful or relevant information from the implementation chapters if he or she doesn't work with the particular database software or programming language that the book incorporates. It is for this reason that I decided to write a book that focuses strictly on the logical design of the database.

Note

I do not cover implementation issues, SQL, or application-programming issues in this work, but there are various books that I do recommend on these topics. You can review my recommendations by accessing my Web site at http://www.ForMereMortals.com.

This book should be easier to read than other books you may have encountered on the subject. Many of the database-design books on the market are highly technical and can be difficult to assimilate. I think most of these books can be confusing and overwhelming if you are not a computer science major, database theorist, or experienced database developer. The design principles you'll learn within these pages are easy to understand and remember, and the examples are common and generic enough to be relevant to a wide variety of situations.

Most people I've met in my travels around the country have told me that they just want to learn how to create a sound database structure without having to learn about normal forms or advanced mathematical theories . Many people are not as worried about implementing a structure within a specific database software as they are about learning how to optimize their data structures and how to impose data integrity. In this book, you'll learn how to create efficient database structures, how to impose several levels of data integrity, as well as how to relate tables together to obtain information in an almost infinite number of ways. Don't worry; this isn't as difficult a task as you might think. You'll be able to accomplish all of this by understanding a few key terms and by learning and using a specific set of commonsense techniques and concepts.

You'll also learn how to analyze and leverage an existing database, determine information requirements, and determine and implement business rules. These are important topics because many of you will probably inherit old databases that you'll need to revamp using what you'll learn by reading this book. They'll also be just as important when you create a new database from scratch.

When you finish reading this book, you'll have the knowledge and tools necessary to create a good relational database structure. I'm confident that this entire approach will work for a majority of developers and the databases they need to create.

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