the systems development environment

8/9/2019 The Systems Development Environment

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© © 2005 by Prentice Hall2005 by Prentice Hall

Chapter 1

The Systems Development

Environment

Dr. Annabella Habinka Ejiri

[email protected]

[email protected]

+256772571444

Information SystemsDevelopment

© © 2005 by Prentice Hall2005 by Prentice Hall1-2

Course outline

Foundations for systems development The systems development environment The origins of software Managing the information systems project

Planning Identifying and selecting systems development projects Initiating and planning systems development projects

Analysis Determining systems requirements Structuring systems process requirements Structuring systems logical requirements Structuring systems data requirements

Design Designing databases Designing forms and reports Designing interfaces and dialogues Finalizing design specifications Designing distributed and internet systems

Implementation and maintenance System implementation Maintaining information systems


Reading list

Systems Analysis and Design, Donald Yeates (2004)

Object Oriented Systems analysis and Design, SimonBennett (1999)

Systems analysis and design, Donald Yeates, TonyWakefield (2004)

Modern systems analysis and design, JeffreyA.Hoffer, Joey F.George, Joseph S.Valacich (2008)

Essentials of systems analysis and design , Jeffrey AHoffer, Joey F.George, Joseph S Valacich (2009)

Systems analysis and design methods, Jeffrey LWhitten, Lonnie D Bentley (2007)


Learning Objectives

Define information systems analysis and design.

Describe the different types of information systems.

Describe the information Systems Development LifeCycle (SDLC).

Explain Rapid Application Development (RAD),prototyping, Joint Application Development (JAD),and Computer Aided Software Engineering (CASE).

Describe agile methodologies and eXtremeprogramming.

Explain Object Oriented Analysis and Design and theRational Unified Process (RUP).


IntroductionInformation Systems Analysis and Design Complex organizational process whereby computer-based

information systems are developed and maintained In System Analysis more emphasis is given to understanding

the details of an existing system or a proposed one and thendeciding whether the proposed system is desirable or notand whether the existing system needs improvements.

Thus, system analysis is the process of investigating asystem, identifying problems, and using the information torecommend improvements to the system.

Application Software Computer software designed to support organizational

functions or processes

Systems Analyst Organizational role most responsible for analysis and design

of information systems


Roles of the systems analyst

Study problems and needs of an organization

Determine best approach to improving

organization through use of: People

Methods

Information technology

Help system users and managers define theirrequirements for new or enhanced systems




Cont…

Assess options for systemimplementation In-house development

Outsourced development

Outsourced development and operation

Commercial application

For in-house projects, work on a teamof analysts and developers


Skills of a Successful SystemsAnalyst

Analytical Understanding of organizations

Problem-solving skills

System thinkingAbility to see organizations and information

systems as systems

Technical Understanding of potential and limitations

of technology


Cont…

Managerial

Ability to manage projects, resources, riskand change

Interpersonal

Effective written and oral communicationskills


Introduction (cont.)


A Modern Approach to SystemsAnalysis and Design

1950s: focus on efficient automation of existingprocesses1960s: advent of 3GL, faster and more reliablecomputers1970s: system development becomes more like anengineering discipline1980s: major breakthrough with 4GL, CASE tools,object oriented methods1990s: focus on system integration, GUI applications,client/server platforms, InternetThe new century: Web application development,wireless PDAs, component-based applications


Types of Information Systemsand Systems Development

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

(transactions) Process orientation

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

meaningful form

Data orientation

Decision Support Systems (DSS) Designed to help decision makers

Provides interactive environment for decision making

Involves data warehouses, executive information systems (EIS)

Database, model base, user dialogue




Types of Information Systemsand Systems Development (cont.)


Developing InformationSystems and the SDLC

System Development Methodology

Standard process followed in anorganization

Consists of:

Analysis

Design

Implementation

Maintenance


Systems Development LifeCycle (SDLC)

Traditional methodology for developing,maintaining, and replacing informationsystems

Phases in SDLC:

Planning

Analysis

Design

Implementation

Maintenance


Standard and Evolutionary Viewsof SDLC


SDLC Planning Phase

Identify, analyze,prioritize, and

arrange IS needs


SDLC Analysis Phase

Study andstructure system

requirements




SDLC Design Phase

Convertrecommendedsolution to system

specifications

Logical design:functional features

described

independently of

computer platform

Physical design:logicalspecifications

transformed to

technology-

specific details


SDLC Implementation Phase

Code, test, install,and support the

information system


SDLC Maintenance Phase

Systematicallyrepair and improvethe information

system



The Heart of the SystemsDevelopment Process

Current practice combines analysis, design, and implementation

into a single iterative and parallel process of activities © © 2005 by Prentice Hall2005 by Prentice Hall1-24

Traditional Waterfall SDLC

One phase begins

when anothercompletes, littlebacktracking and

looping




Problems with WaterfallApproach

System requirements “locked in” afterbeing determined (can't change)

Limited user involvement (only inrequirements phase)

Too much focus on milestone deadlinesof SDLC phases to the detriment ofsound development practices


Alternatives to TraditionalWaterfall SDLC

Prototyping

CASE tools

Joint Application Design (JAD)

Rapid Application Development (RAD)

Agile Methodologies

eXtreme Programming


Prototyping

Iterative development process:

Requirements quickly converted to a working system

System is continually revised

Close collaboration between users and analysts


CASE Tools

Computer-Aided Software Engineering

Software tools providing automatedsupport for systems development

Project dictionary/workbook: systemdescription and specifications

Diagramming tools

Example products: Oracle Designer,Rational Rose


Joint Application Design (JAD)

Structured process involving users,analysts, and managers

Several-day intensive workgroupsessions

Purpose: to specify or review systemrequirements


Rapid Application Development(RAD)

Methodology to decrease design and implementation time

Involves: prototyping, JAD, CASE tools, and codegenerators




Agile Methodologies

Motivated by recognition of softwaredevelopment as fluid, unpredictable,

and dynamic

Three key principles

Adaptive rather than predictive

Emphasize people rather than roles

Self-adaptive processes


eXtreme Programming

Short, incremental development cycles

Automated tests

Two-person programming teams

Coding and testing operate together

Advantages: Communication between developers

High level of productivity

High-quality code


Object-Oriented Analysis andDesign

Based on objects rather than data orprocesses

Object: a structure encapsulating attributesand behaviors of a real-world entity

Object class: a logical grouping of objectssharing the same attributes and behaviors

Inheritance: hierarchical arrangement ofclasses enable subclasses to inheritproperties of superclasses


Rational Unified Process (RUP) involves an iterative,incremental approach to systems development


Summary

In this chapter you learned how to: Define information systems analysis and design. Describe the different types of information

systems.

Describe the information Systems DevelopmentLife Cycle (SDLC). Explain Rapid Application Development (RAD),

prototyping, Joint Application Development (JAD),and Computer Aided Software Engineering(CASE).

Describe agile methodologies and eXtremeprogramming.

Explain Object Oriented Analysis and Design andthe Rational Unified Process (RUP).

the systems development environment

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