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. 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. After completing this milestone, you should be able to: Before starting this milestone, the following topics should be covered: • Process Modeling – Chapter 9 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 of the methodology have been completed and you understand the current system’s strengths, weaknesses
, limitations, problems, opportunities, and constraints. You have already built the Context models (Milestone 3) to document business requirements for the new system. You now need to build the Level 0 (System) DFD and corresponding process models. Deliverable format and software to be used are according to your instructor’s specifications. Deliverables should be neatly packaged in a binder, separated with a tab divider labeled “Milestone 5-Part II”. • Context Data Flow Diagram Narrative – Exhibit 5.1 The software design technique which is based on the composing software from separate, interchangeable components is known as the Modular design is a way to organize the complex system as a set of distinct components. Components may be developed, tested independently and then plugged together. Modular design is supported by three types of logic: Sequential; Decision making or control; Iteration or repetition. – execution of steps one after another. – execution of step depends on results of condition or set of conditions. Decision making is also called the selection or control. – execution of steps is repeated until the specific condition changes. Iteration is also called as repetition or looping. In this milestone you will write the Structured English for primitive process. After completing this milestone, you should be able to: Before starting this milestone the following topics should be covered: Child level DFD – Chapter 9 Physical level DFD – Chapter 9 and12 Structured English – Chapter 9 Fact-finding results – Chapter 6 Write the Structured English for one-two primitive processes. Include sequential, decision making and iteration logics. Your instructor will indicate what specific processes to document.