Fact finding techniques in database

Structure of this Chapter

In Section 11.1Section 11.1 we discuss when a database developer might use

fact-finding techniques. (Throughout this book we use the term

“database developer” to refer to a person or group of people

responsible for the analysis, design, and implementation of a

database system.) In Section 11.2Section 11.2 we illustrate the types of facts that

should be collected and the documentation that should be produced

at each stage of the database system development lifecycle. In

Section 11.3Section 11.3 we describe the five most commonly used fact-finding

techniques and identify the advantages and disadvantages of each. In

Section 11.4Section 11.4 we demonstrate how fact-finding techniques can be

used to develop a database system for a case study called

DreamHome, a property management company. We begin this section

by providing an overview of the DreamHome case study. We then

examine the first three stages of the database system development

lifecycle, namely database planning, system definition, and

requirements collection and analysis. For each stage we demonstrate

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328of each. We finally demonstrate how some of these techniques may be used during the earlier stages of the database system development lifecycle using a property management company called DreamHome. The DreamHome case study is used throughout this book.

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the process of collecting data using fact-finding techniques and

describe the documentation produced.

11.1 When Are Fact-Finding Techniques Used?

There are many occasions for fact-finding during the database system

development life cycle. However, fact-finding is particularly crucial to

the early stages of the lifecycle, including the database planning,

system definition, and requirements collection and analysis stages. It

is during these early stages that the database developer captures the

essential facts necessary to build the required database. Fact-finding is

also used during database design and the later stages of the lifecycle,

but to a lesser extent. For example, during physical database design,

fact-finding becomes technical as the database developer attempts to

learn more about the DBMS selected for the database system. Also,

during the final stage, operational maintenance, fact-finding is used to

determine whether a system requires tuning to improve performance

or further development to include new requirements.

Note that it is important to have a rough estimate of how much time

and effort is to be spent on fact-finding for a database project. As we

mentioned in Chapter 10Chapter 10, too much study too soon leads to paralysis

by analysis. However, too little thought can result in an unnecessary

waste of both time and money, due to working on the wrong solution

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to the wrong problem.

11.2 What Facts Are Collected?

Throughout the database system development lifecycle, the database

developer needs to capture facts about the current and/or future

system. Table 11.1Table 11.1 provides examples of the sorts of data captured

and the documentation produced for each stage of the lifecycle. As we

mentioned in Chapter 10Chapter 10, the stages of the database system

development lifecycle are not strictly sequential, but involve some

amount of repetition of previous stages through feedback loops. This

is also true for the data captured and the documentation produced at

each stage. For example, problems encountered during database

design may necessitate additional data capture on the requirements

for the new system.

TABLE 11.1 Examples of the data captured and the documentation produced for each stage of the database system development lifecycle.

STAGE OF DATABASESTAGE OF DATABASE

SYSTEMSYSTEM

DEVELOPMENTDEVELOPMENT

LIFECYCLELIFECYCLE

EXAMPLES OF DATAEXAMPLES OF DATA

CAPTUREDCAPTURED

EXAMPLES OFEXAMPLES OF

DOCUMENTATIONDOCUMENTATION

PRODUCEDPRODUCED

Database planning Aims and objectives of Mission statement

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database project and objectives of

database system

System definition Description of major

user views (includes

job roles or business

application areas)

Definition of scope

and boundary of

database system;

definition of user

views to be

supported

Requirements

collection and analysis

Requirements for user

views; systems