System analysis and design

CIS 315 – Hatim Mouissa

Chapter 1:

Introduction to Systems

Analysis and Design

CIS 315 – Hatim Mouissa

Objectives

 Understand the fundamental systems

development life cycle and its four phases.

 Understand the evolution of systems

development methodologies.

 Be familiar with the Unified Process and

its extensions.

 Be familiar with the different roles on the

project team.

SYSTEMS DEVELOPMENT LIFE CYCLE

CIS 315 – Hatim Mouissa

Systems Development Life Cycle

Planning

Analysis

Design

Implementation

We will explore each phase in detail in the next slides

CIS 315 – Hatim Mouissa

SDLC: Planning

1. Project Initiation

◦ Develop a system request

◦ Conduct a feasibility analysis

2. Project Management

◦ Develop work plan

◦ Staff the project

◦ Control and direct the project

Why should we build this system?

CIS 315 – Hatim Mouissa

SDLC: Analysis

1. Develop analysis strategy

2. Gather requirements

3. Develop a system proposal

What should the system do for us? Where and when will it be used?

CIS 315 – Hatim Mouissa

SDLC: Design

1. Develop a design strategy

2. Design architecture and interfaces

3. Develop databases and file specifications

4. Develop the program design

How will we build the system?

CIS 315 – Hatim Mouissa

SDLC: Implementation

1. Construct system

2. Install system

◦ Implement a training plan for the users

3. Establish a support plan

Build the system!

CIS 315 – Hatim Mouissa

Putting the SDLC Together

 Each phase consists of steps that lead to

specific deliverables

 The system evolves through gradual

refinement

 Once the system is implemented, it may

go back into a planning phase for its next

revision, a follow-on system, or

maintenance releases

CIS 315 – Hatim Mouissa

Processes and Deliverables

Process Product

Planning

Analysis

Design

Implementation

Project Plan

System Proposal

System

Specification

New System and

Maintenance Plan

SYSTEMS DEVELOPMENT METHODOLOGIES

CIS 315 – Hatim Mouissa

Systems Development

Methodologies  A methodology is a formalized approach to

implementing the SDLC

 Well-known methodologies include:

◦ Waterfall development

◦ Parallel development

◦ Rapid application development

◦ Agile development

CIS 315 – Hatim Mouissa

Categories of Methodologies

• Structured Design

–Waterfall Development

–Parallel Development

• Rapid Application Development

–Phased

–Prototyping

–Throwaway Prototyping

• Agile Development

–eXtreme Programming

CIS 315 – Hatim Mouissa

Structured Design 1

Waterfall Development

CIS 315 – Hatim Mouissa

Structured Design 2

Parallel Development

CIS 315 – Hatim Mouissa

Rapid Application Development 1

Phased Development

CIS 315 – Hatim Mouissa

Rapid Application Development 2

System Prototyping

CIS 315 – Hatim Mouissa

Rapid Application Development 3

Throwaway Prototyping

CIS 315 – Hatim Mouissa

Agile Development

Extreme Programming

CIS 315 – Hatim Mouissa

Selecting the Right Methodology

Usefulness

for

Waterfal

l

Paralle

l

Phased Prototypi

ng

Throwawa

y

Prototypi

ng

Extreme

Programmi

ng

Unclear user

requirements

Poor Poor Good Excellent Excellent Excellent

Unfamiliar

technology

Poor Poor Good Poor Excellent Poor

Complex

systems

Good Good Good Poor Excellent Poor

Reliable

systems

Good Good Good Poor Excellent Good

Short time

schedule

Poor Good Excellent Excellent Good Excellent

Schedule

visibility

Poor Poor Excellent Excellent Good Good

CIS 315 – Hatim Mouissa

Object-Oriented Analysis & Design

 Attempt to balance emphasis on data and

process

 Uses Unified Modeling Language (UML)

 Characteristics of OOAD:

◦ Use-case Driven

◦ Architecture Centric

◦ Iterative and Incremental

THE UNIFIED PROCESS

CIS 315 – Hatim Mouissa

The Unified Process

 A specific methodology that maps out when and how to use the various UML techniques for object-oriented analysis and design

 A two-dimensional process consisting of phases and flows

◦ Phases describe how the system evolves over time

◦ Workflows are collections of tasks that occur throughout the lifecycle, but vary in intensity

CIS 315 – Hatim Mouissa

The Unified Process

CIS 315 – Hatim Mouissa

Unified Process Phases

 Inception

 Elaboration

 Construction

 Transition

CIS 315 – Hatim Mouissa

Engineering Workflows

 Business modeling

 Requirements

 Analysis

 Design

 Implementation

 Testing

 Deployment

CIS 315 – Hatim Mouissa

Supporting Workflows

 Project management

 Configuration and change management

 Environment

 Operations and support*

 Infrastructure management*

* Part of the enhanced unified process

THE UNIFIED MODELING LANGUAGE

CIS 315 – Hatim Mouissa

Unified Modeling Language

 Provides a common vocabulary of object-

oriented terms and diagramming

techniques rich enough to model any

systems development project from

analysis through implementation

 Version 2.0 has 14 diagrams in 2major

groups:

◦ Structure diagrams

◦ Behavior diagrams

CIS 315 – Hatim Mouissa

UML Structure Diagrams

 Represent the data and static

relationships in an information system

◦ Class

◦ Object

◦ Package

◦ Deployment

◦ Component

◦ Composite structure

CIS 315 – Hatim Mouissa

UML Behavior Diagrams

 Depict the dynamic relationships among the

instances or objects that represent the

business information system

– Activity

–Sequence

– Communication

– Interaction overview

–Timing

– Behavior state machine

–Protocol state

machine,

– Use-case diagrams

CIS 315 – Hatim Mouissa

Summary

 The Unified Process is a two-dimensional

systems development process described

with a set of phases and workflows

 The Unified Modeling Language, or UML,

is a standard set of diagramming

techniques