Database DesignOverview and Principles

Why Design?

A well designed relational database maintains data integrity and allows you to access any data and compare it to any other data.

A poorly designed relational database can make it impossible to retrieve or enter needed information

Taking the time to carefully design a database is essential

Advantages of Methodology It gives you the skills you need to

to design a sound database Provides an organized set of

techniques and procedures Helps reduce missteps Makes design easier and faster

Objectives of Good Design A database that supports

required and ad hoc queries Proper and efficient table

structure Data integrity at all levels Support of business rules Scalable: supports future growth

Design Methods

Traditional database design methods incorporate 3 phases Requirements analysis Data modeling Normalization

Note on Normalization “Normalization is the process of

decomposing large tables into smaller ones in order to eliminate redundant data and duplicate data and to avoid problems with inserting, updating, or deleting data.” page 36

The author incorporates Normalization into his method without treating it specifically.

We will cover it briefly because you will be expected to know what is meant by Normal forms, etc.

Note:

This PowerPoint is based on Chapter Two of Database Design For mere Mortals 2nd Edition by Michael J. Hernandez