ABSTRACT
Data are the heart of the data processing system, while software is the brains. We need to design data well if we wish to achieve a robust software product. For this, the first step is to understand the data thoroughly. We have three major classes of data, namely application data used by the end users in performing business transactions, parameter data that are used to configure the software application, and the security data that are used to safeguard the application artifacts and data as well as to assist in the investigation of a security incident. In these major classes of data, we have subclasses. The first design decision is to select the best type of data storage between flat files and DBMS tables. Each has its own advantages and disadvantages. While the present-day practice is to use DBMS tables for most of the data, flat files are still in use. Especially for some parameter and security data, flat files are the better choice. For application data, however, DBMS tables are most apt. Security data consist of audit trails, session details, login details, parameter change details, security data change details, and so on. This chapter discusses all these details and how to design our application so that it works efficiently while ensuring security, safety, data integrity, minimized data redundancy, and so on.
