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Essentials of

Systems Analysis and DesignFifth Edition Joseph S. Valacich Joey F. George

Jerey A. Hoer

Chapter 1he Systems De!elopment

En!ironment

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Learning Objectives

Defne inormation systems analysisand design

Discuss the modern approach tosystems analysis and design thatcombines both process and data viewso systems

Describe the role o the systemsanalyst in inormation systemsdevelopment

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Learning Objectives(continued)

Describe the inormation systemsdevelopment lie cycle (SDLC)

List alternatives to the systemsdevelopment lie cycle including adescription o the role o computeraided sotware engineering (C!S")tools in systems development


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Chapter #review

Systems !nalysis is a proven methodto help a business utili$e inormation to

its ullest capacity Systems Development Lie Cycle

(SDLC)

› Central to %normation SystemsDevelopment


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&hat is %normationSystems !nalysis and

Design' ! method used by companies to create

and maintain systems that perormbasic business unctions

ain goal is to improve employeeeciency by applying sotwaresolutions to *ey business tas*s

! structured approach must be used inorder to ensure success

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&hat is %normation Systems!nalysis and Design' (continued)

Systems !nalysts perorm analysis anddesign based upon+›

,nderstanding o organi$ation-s objectivesstructure and processes

› .nowledge o how to e/ploit inormationtechnology or advantage

0ig 121 illustrates the SystemsDevelopment Lie Cycle a our2phasedapproach used throughout this te/t

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Systems !nalysis andDesign+ Core Concepts

ajor goal+ to improve organi$ationalsystems by developing or ac3uiringapplication sotware and trainingemployees in its use

!pplication sotware or a systemsupports organi$ational unctions or

processes

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Systems !nalysis andDesign+ Core Concepts

(continued) System+ 4urns data into inormation and

includes+› 5ardware and system sotware

› Documentation and training materials

› 6ob roles associated with the system

› Controls to prevent thet or raud

› 4he people who use the sotware to perorm

their jobs 0igure 178 illustrates all the components

o a system

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Sotware "ngineering#rocess

! process used to create an inormationsystem

Consists o+› ethodologies

! se3uence o step2by2step approaches that helpdevelop the inormation system

› 4echni3ues

#rocesses that the analyst ollows to ensure thoroughcomplete and comprehensive analysis and design

› 4ools Computer programs that aid in applying techni3ues


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System

! system is an interrelated set obusiness procedures used within onebusiness unit wor*ing together or apurpose

! system has nine characteristics ! system e/ists within an environment

! boundary separates a system romits environment


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Characteristics o a System

Components %nterrelated Components

9oundary #urpose "nvironment %nteraces

Constraints %nput Output

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%mportant System Concepts

Decomposition› 4he process o brea*ing down a system into

smaller components

› !llows the systems analyst to+ 9rea* a system into small manageable and

understandable subsystems 0ocus on one area at a time without intererence

rom other areas Concentrate on component pertinent to one group

o users without conusing users with unnecessarydetails

9uild di:erent components at independent timesand have the help o di:erent analysts


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%mportant System Concepts(continued) odularity

› #rocess o dividing a system intomodules o a relatively uniorm si$e

› odules simpliy system design

Coupling› Subsystems that are dependent upon

each other are coupled

Cohesion› "/tent to which a subsystem perorms a

single unction

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! odern !pproach toSystems !nalysis and

Design Systems %ntegration

› !llows hardware and sotware rom

di:erent vendors to wor* together› "nables procedural language systems to

wor* with visual programming systems

› ;isual programming environment uses

client

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=our >ole in SystemsDevelopment

Study problems and needs o anorgani$ation

Determine best approach to improvingorgani$ation through use o+› #eople

› ethods

› %normation technology

5elp system users and managers defnetheir re3uirements or new or enhancedinormation systems


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Developing %normation Systems andthe Systems Development Lie Cycle

Systems Development ethodology

› ! standard process ollowed in anorgani$ation to conduct all the stepsnecessary to

analy$e

design

implement

and maintain inormation systems7


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Developing %normation Systems and theSystems Development Lie Cycle(continued)

Systems Development Lie Cycle› Series o steps used to manage the phases

o development or an inormation system

› Consists o our phases+ #lanning and Selection !nalysis Design

%mplementation and Operation


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Developing %normation Systems and theSystems Development Lie Cycle(continued)

› #hases are not necessarily se3uential

› "ach phase has a specifc outcome anddeliverable

› "very company customi$es the lie2cyclemodel to its individual needs


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#hases o the SystemsDevelopment Lie Cycle

17 Systems #lanning and Selection› 4wo ain !ctivities

%dentifcation o need

%nvestigation and determination o scope

87 Systems !nalysis› Study o current procedures and inormation

systems

Determine re3uirements ?enerate alternative designs Compare alternatives >ecommend best alternative


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#hases o the Systems DevelopmentLie Cycle (continued)

@7 System Design› Logical Design

Concentrates on business aspects o the system

› #hysical Design 4echnical specifcations

A7 System %mplementation and Operation› %mplementation

5ardware and sotware installation #rogramming ,ser 4raining Documentation


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#hases o the Systems DevelopmentLie Cycle (continued)

System %mplementation and Operation(continued)

System changed to reBect changingconditions

System obsolescence


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!lternative !pproaches toDevelopment

#rototyping

› 9uilding a scaled2down wor*ing version othe system

› !dvantages+

,sers are involved in design

Captures re3uirements in concrete orm

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!lternative !pproaches toDevelopment (continued)

Computer2!ssisted Sotware"ngineering (C!S") 4ools

›

!utomated sotware tools used by systemsanalysts to develop inormation systems

› Can be used throughout SDLC

› #roduct and tool integration is provided

through a repository

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› ?eneral types o C!S" tools

Diagramming tools

Computer display and report generators

!nalysis tools

>epository

Documentation generators

Code generators

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6oint !pplication Design (6!D)› ,sers anagers and !nalysts wor*

together or several days

› System re3uirements are reviewed

› Structured meetings

>apid !pplication Development (>!D)›

,tili$es prototyping to delay producingsystem design until ater userre3uirements are clear


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!pproaches to Development(continued)

#articipatory Design (#D)› "mphasi$es role o the user

› "ntire user community can be involved indesign

!gile ethodologies› 0ocuses on

!daptive methodologies #eople instead o roles Sel2adaptive development process


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Summary

%normation systems analysis anddesign

›

#rocess o developing and maintaining aninormation system

odern approach to systems analysis

› #rocess2oriented

› Data2oriented


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Summary (continued)

>ole o Systems !nalyst Systems Development Lie Cycle (SDLC)

› Systems #lanning and Selection

› Systems !nalysis

› Systems Design

› Systems %mplementation


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Summary (continued)

!lternatives to Systems Development LieCycle› #rototyping

› >apid !pplication Development (>!D)› C!S"

› 6oint !pplication Design (6!D)

› #articipatory Design (#D)

› !gile ethodologies

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Esad5e Pp Ch01