WebSphere Application Server - IBM Redbooks

► The introduction guide at:
http://jakarta.apache.org/struts/userGuide/introduction.html
► The following articles on Struts in the VisualAge for Java zone of WebSphere
Developer Domain at:
http://www7b.software.ibm.com/wsdd/
– Apache Struts and VisualAge for Java, Part 1: Building Web-based
Applications using Apache Struts
– Apache Struts and VisualAge for Java, Part 2: Using Struts in VisualAge
for Java 3.5.2 and 3.5.3
2.5 Designing the database
2.5.1 Normalization
Database design is one of the most important steps in Web application design.
Here we will discuss a few things to be kept in mind as we develop the database
model for our application. When you design tables you must choose an
appropriate data model and data types for them. You also need to be aware of
the pros and cons of creating indexes and be thoughtful in determining their
usefulness.
In this section, we will explain some database concepts that need to be applied
to create a sound, efficient data model.
Normalization is the process of determining the structure of database tables. The
objective is to introduce flexibility into the structure, while reducing redundant
data. The reduction in data can improve the performance of update and delete
statements, since the data is only touched once. By normalizing data, you try to
ensure that all columns in the table depend on the primary key.
There are four levels or degrees of normalization. We will limit our discussion to
the third normal form for the sake of simplicity and to be within the scope of this
publication.
First normal form
In the first normal form, each cell in the table is atomic, meaning that it contains
only one value.
Second normal form
In the second normal form, each non-key column is dependent upon the entire
key and not just part of the composite key.
Chapter 2. Application design 37