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Systems Analysis and

Design 10

th

Edition

Chapter 4 Requirements Modeling



Describe systems analysis phase activities



Explain joint application development

(JAD), rapid application development

(RAD), and agile methods



Use a functional decomposition diagram

(FDD) to model business functions and

processes



Describe the Unified Modeling Language

(UML) and examples of UML diagrams

Chapter Objectives

Systems Analysis Phase Overview 

Systems Analysis Phase Overview

◦ (^) Understand the proposed project ◦ (^) Ensure that it supports business requirements ◦ (^) Build a solid foundation for system development 

Systems Analysis Activities

◦ (^) Requirements Modeling ◦ (^) Data and Process Modeling ◦ (^) Object Modeling ◦ (^) Development Strategies

Systems Analysis Phase Overview (Cont.) FIGURE 4-2 The systems analysis phase consists of requirements modeling, data and process modeling, object modeling, and consideration of development strategies. Notice that the systems analysis tasks are interactive, even though the waterfall model generally depicts sequential development  Requirements Modeling ◦ (^) Fact-finding to describe the current system ◦ (^) Requirements for new system  Data and Process Modeling ◦ (^) Graphically represent system data and processes  Object Modeling ◦ (^) Create objects to represent things, transactions and events  Development Strategies ◦ (^) Software trends, development alternatives, outsourcing, etc.

Joint Application Development  Brings users into the development process as active participants  User Involvement (formally or informally) created a successful system 

JAD Participants and Roles

◦ (^) Project leader and one or more members ◦ (^) Participants insulated from distractions of day-to-day operations

Joint Application Development (Cont.) FIGURE 4-3 Typical JAD participants and roles

Joint Application Development (Cont.) JAD Disadvantages 

JAD is more expensive than traditional methods



Can be cumbersome if group is too large

JAD Advantages 

JAD allows key users to participate effectively



Users more likely to feel a sense of ownership



Produces a more accurate statement of system

requirements

Rapid Application Development  Uses a group approach like JAD  JAD produces a requirements model, RAD produces a new system  Complete methodology ◦ (^) Four-phase life cycle that parallels the traditional SDLC ◦ (^) Reduces cost and development time ◦ (^) Increases the probability of success ◦ (^) Relies on prototyping and user involvement ◦ (^) Prototypes modified based on user input

Rapid Application Development (Cont.) 

Requirements Planning

◦ (^) Team agrees on business needs, project scope, constraints, and system requirements ◦ (^) Management authorization to continue is obtained 

User Design

◦ (^) Users interact with analysts to develop models and prototypes ◦ (^) A combination of JAD and CASE tools are used ◦ (^) Users understand, modify, and approve a working model

Rapid Application Development (Cont.) 

Construction

◦ (^) Program and application development ◦ (^) Users can suggest changes as screens or reports are developed 

Cutover

◦ (^) Includes data conversion, testing, changeover to the new system, and user training

Agile Methods  Agile methods attempt to develop a system incrementally, by building a series of prototypes and constantly adjusting them to user requirements  Developers revise, extend, and merge earlier versions into the final product  Emphasizes continuous feedback, and each incremental step is affected by what was learned in the prior steps

Agile Methods (Cont.) FIGURE 4-6 Agilian supports various modeling tools, such as the Unified Modeling Language, use cases, and business process modeling, among others

Agile Methods (Cont.) 

Agile Method Advantages and

Disadvantages

◦ (^) Very flexible and efficient in dealing with change ◦ (^) Frequent deliverables constantly validate the project and reduce risk ◦ (^) Team members need a high level of technical and interpersonal skills ◦ (^) May be subject to significant change in scope

Modeling Tools and Techniques  Involves graphical methods and nontechnical language that represent the system at various stages of development  Can use various tools  Functional Decomposition Diagrams ◦ (^) Functional decomposition diagram (FDD) ◦ (^) Model business functions and show how they are organized into lower-level processes