Milestone 5 – Process Modeling - Part Ii

MILESTONE 5 – PROCESS MODELING - Part II (Exploded DFD)

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Part 1

Synopsis

Level 0 Data flow Diagram

T

he requirements analysis phase answers the question, ‘What does the user need and want from a new system?’ The requirements analysis phase is critical to the success of any new information system! In this milestone we need to identify what information systems requirements need to be defined from the system users’ perspectives.

The Data Flow Diagram (DFD) is a graphical representation of system which shows systems structure and components. The DFD shows how the data transforms in the system, what the source of the input is and what is the destination. Also, the DFD presents data structure and how it’s stored.

In this milestone you will explode the Context level DFD to Level 0 DFD to show sub-systems (processes). The Level 0 DFD shows internal data stores and how data flows through the processes.

Child diagram definition

C

hild level diagrams show details and are built till needed level of details is reached. First, we show the information system as a single process on the Context diagram. Then, we decompose and show more details until all processes are functional primitives. Not all processes are exploded to the same number of levels- it’s not required to explode all processes to the same level. The main target is to reach the functional primitive which will be translated into units of program code.

Objectives

After completing this milestone, you should be able to:

Create a Level 0 (System) Data Flow Diagram

Create a Child Data Flow Diagram

Prerequisites

Before starting this milestone, the following topics should be covered:

• Process Modeling - Chapter 9

Assignment

As a systems analyst or knowledgeable end-user, you must learn how to draw data flow diagrams to model business process requirements. The preliminary investigation and problem analysis phases...