Copyright 2002 Prentice-Hall, Inc.

Chapter 1

The Systems Development Environment

1.11.1

Modern Systems Analysisand Design

Third Edition

Jeffrey A. Hoffer Joey F. George

Joseph S. Valacich

Learning Objectives

üDefine information systems analysis and design

üDiscuss the modern approach to systems analysis and design

üDescribe the organizational roles involved in information systems development

1.21.2

Learning Objectives

üDescribe four types of information systems:üTransaction Processing Systems (TPS)

üManagement Information Systems (MIS)

üDecision Support Systems (DSS)

üExpert Systems (ES)

üDescribe the information systems development life cycle (SDLC)

1.31.3

Learning Objectives

üDiscuss alternatives to the systems development life cycle

üDiscuss the role of computer-aided software engineering (CASE) tools in systems development

1.41.4

Introduction

Information Systems Analysis and Designn Complex process whereby computer-

based information systems are developed and maintained

Application Softwaren Result of systems analysis and design

n Designed to support specific organizational functions or processes

1.51.5

Introduction

Software engineering processes have been developed to assist in analysis and designn Methodologiesw Comprehensive, multi-step approaches to systems

development

n Techniquesw Processes that are followed to ensure that work is well

thought-out, complete and comprehensible to others on the project team

n Toolsw Computer programs to assist in application of techniques

to the analysis and design process

1.61.6

Introduction

Information Systems Analysis and Design

n A method used by companies to create and maintain systems that perform basic business functions

n Main goal is to improve employee efficiency by applying software solutions to key business tasks

n A structured approach must be used in order to ensure success

1.71.7

Introduction

Systems Analyst performs analysis and design based upon:

n Understanding of organization’s objectives, structure and processes

n Knowledge of how to exploit information technology for advantage

1.81.8

Software Engineering Process

A process used to create an information system

Consists of:n Methodologiesw A sequence of step-by-step approaches that help

develop the information system

n Techniquesw Processes that the analyst follows to ensure thorough,

complete and comprehensive analysis and design

n Toolsw Computer programs that aid in applying techniques

1.111.11

Data and Processes

Three key components of an information systemn Data

n Data Flows

n Processing Logic

Data vs. Informationn Dataw Raw facts

n Informationw Derived from data

w Organized in a manner that humans can

understand.1.1.

Data and Processes

Data

n Understanding the source and use of data is key to good system design

n Various techniques are used to describe data and the relationship amongst data

Data Flows

n Groups of data that move and flow through the system

1.1.

Data and Processes

Data Flows (Continued)

n Include description of sources and destination for each data flow

Processing Logic

n Describe steps that transform data and events that trigger the steps

1.1.

Differences among data, data flow, and processing logic

1.131.13

Approaches to Systems Development

Process-Oriented Approachn Focus is on flow, use and transformation of data in

an information system

n Involves creating graphical representations such as data flow diagrams and charts

n Data are tracked from sources, through intermediate steps and to final destinations

n Natural structure of data is not specified

n Disadvantage: data files are tied to specific applications

1.1.

Approaches to Systems Development

Data-Oriented Approach

n Depicts ideal organization of data, independent of where and how data are used

n Data model describes kinds of data and business relationships among the data

n Business rules depict how organization captures and processes the data

1.1.

Databases and Application Independence

Databasen Shared collection of logically related data

n Organized to facilitate capture, storage and retrieval by multiple users

n Centrally managed

n Designed around subjectsw Customers

w Suppliers

Application Independencen Separation of data and definition of data from

applications1.1.

Traditional relationship between data and applications,With redundant data, versus the database approach

(a) Traditional approach

(b) Databaseapproach

1.171.17

1.181.18

Organizational Responsibilities in Systems Development

Systems Analysts work in teamsn Project Basedn Includesw IS Managerw Programmersw Usersw Other specialists

1.1.

Organization chart for typical IS department

1.201.20

1.211.21

Organizational Responsibilities in Systems Development

IS Managern May have a direct role in systems

development if the project is small

n Typically involved in allocating resources to and overseeing system development projects.

Systems Analystn Key individuals in the systems

development process

Typical job for a systems analyst

1.221.22

Organizational Responsibilities in Systems Development

Skills of a Successful Systems Analyst n Analyticalw Understanding of organizations

w Problem solving skills

w System thinkingn Ability to see organizations and information systems as

systems

n Technicalw Understanding of potential and limitations of technology

n Managementw Ability to manage projects, resources, risk and change

n Interpersonalw Effective written and oral communication skills

1.1.

Organizational Responsibilities in Systems Development

Programmersn Convert specifications into instructions that

the computer understands

n Write documentation and testing programs

Business Managersn Have power to fund projects and allocate

resources

n Set general requirements and constraints for projects

1.1.

Organizational Responsibilities in Systems Development

Other IS Managers/Technicians

n Database Administratorw Involved in design, development and maintenance of

databases

n Network and telecommunications experts

w Develop systems involving data and/or voice communications

n Human Factors Specialistsw Involved in training users and writing documentation

1.1.

Types of Information Systemsand Systems Development

Transaction Processing Systems (TPS)n Automate handling of data about business

activities (transactions)

Management Information Systems (MIS)n Converts raw data from transaction processing

system into meaningful form

Decision Support Systems (DSS)n Designed to help decision makers

n Provides interactive environment for decision making

1.1.

Types of Information Systemsand Systems Development

Expert Systems (ES)

n Replicates decision making process

n Knowledge representation describes the way an expert would approach the problem

1.1.

1.1.

Systems Development Life Cycle

System Development Methodology

n Standard process followed in an organization

n Consists of:

w Analysis

wDesign

w Implementation

wMaintenance

1.1.

Systems Development Life Cycle

Series of steps used to manage the phases of development for an information system

Consists of six phases:

n Project Identification and Selection

n Project Initiation and Planning

n Analysis

n Design

n Implementation

n Maintenance

1.1.

The system development life cycle

1.1.

Systems Development Life Cycle

n Phases are not necessarily sequential

n Each phase has a specific outcome and deliverable

n Individual companies use customized life cycles

1.1.

Phases of the Systems Development Life Cycle

Project Identification and Selectionn Two Main Activitiesw Identification of need

w Prioritization and translation of need into a development schedule

n Helps organization to determine whether or not resources should be dedicated to a project.

Project Initiation and Planningn Two Activitiesw Formal preliminary investigation of the problem at hand

w Presentation of reasons why system should or should not be developed by the organization

1.1.

Systems Development Life Cycle

Analysis

n Study of current procedures and information systems

wDetermine requirementsn Study current system

n Structure requirements and eliminate redundancies

wGenerate alternative designs

wCompare alternatives

wRecommend best alternative

1.1.

Systems Development Life Cycle

Designn Logical Designw Concentrates on business aspects of the system

n Physical Designw Technical specifications

Implementationn Implementationw Hardware and software installation

w Programming

w User Training

w Documentation

1.1.

Systems Development Life Cycle

Maintenancew System changed to reflect changing conditions

w System obsolescence

1.1.

Approaches to Development

Prototyping

n Building a scaled-down working version of the system

n Advantages:

w Users are involved in design

w Captures requirements in concrete form

Rapid Application Development (RAD)

n Utilizes prototyping to delay producing system design until after user requirements are clear

1.1.

Rapid application development SDLC

1.1.

Evolutionary model SDLC

1.1.

1.1.

Approaches to Development

Joint Application Design (JAD)

n Users, Managers and Analysts work together for several days

n System requirements are reviewed

n Structured meetings

1.1.

Improving IS Development Productivity

Computer-aided software engineering (CASE) tools

n Facilitate creation of a central repository for system descriptions and specifications

1.1.

Summary

Information systems analysis and design

n Process of developing and maintaining an information system

Modern approach to systems analysis

n Process-Oriented

n Data-Oriented

1.1.

Summary

Four types of information systems

n Transaction Processing (TPS)

n Management Information Systems (MIS)

n Decision Support (DSS)

n Expert Systems (ES)

1.1.

Summary

Systems Development Life Cycle (SDLC)n Project Identification and Selection

n Project Initiation and Planning

n Analysis

n Design

n Implementation

n Maintenance

1.1.

Summary

Alternatives to Systems Development Life Cycle

n Prototyping

n Rapid Application Development (RAD)

n Joint Application Design (JAD)

Computer-aided software engineering (CASE) tools

1.1.