Slide 1 Introduction to Systems Analysis and Design
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Transcript of Slide 1 Introduction to Systems Analysis and Design
Slide 1
Introduction to Systems Analysis and Design
Chapter 1
Slide 2
Key Ideas
More than ½ of all IS development projects Fail.
Canceled before completionSystem is never used once finishedDoesn't provide the expected benefits
Most of the ones that don't fail:Are delivered lateAre over budgetDon't provide the features promised
Slide 3
Key Ideas
Many fail because analysts try to build wonderful systems without understanding the organization.The primarily goal is to create value for the organization.
Slide 4
Key Ideas
The systems analyst is a key person analyzing the business, identifying opportunities for improvement, and designing information systems to implement these ideas.It is important to understand and develop through practice the skills needed to successfully design and implement new information systems.
Slide 5
THE SYSTEMS DEVELOPMENT LIFE CYCLE
Slide 6
Major Attributes of the Lifecycle
The projectMoves systematically through phases where each phase has a standard set of outputsProduces project deliverablesUses deliverables in implementationResults in actual information systemUses gradual refinement
Slide 7
Project Phases
PlanningWhy build the system?
AnalysisWho, what, when, where will the system be?
DesignHow will the system work?
ImplementationSystem delivery
Slide 8
Identifying business valueLower costs / Increase profits
Analyze feasibilityDevelop work planStaff the projectControl and direct project
Planning
Slide 9
Project Initiation
Planning
System Request
Feasibility Analysis
Approval Committee
Project Management
Slide 10
Answer the Questions:Who will use the system?What will the system do?When will it be used?
Investigate the current systemIdentify possible improvementsDevelop a concept for new system
Analysis
Slide 11
Analysis
Develops an Analysis Strategy which includes:
Analyze current system & its problemsInformation gathering
Interviews with users Input from project sponsor and requestor Leads to concept for new system
Process and Data modeling Models describe how business process will work
with the new system
Slide 12
Analysis
Analysis+ System Concept
+ Models
are combined into theSystem Proposal
Slide 13
Decides how the system will operateDesign strategy
Design internallyOutsource designBuy off the shelf
Architecture designHardware descriptionSoftware descriptionNetwork infrastructure
Design
Slide 14
Design
Interface designHow users interact with systemForms / reports used by the system
Database and file SpecificationWhat data is to be storedWhat format the data will be inWhere the data will be stored
Slide 15
Design
Program designWhat programs need to be writtenExactly what each program will do
Slide 16
Design
These deliverables:Architecture designInterface designDatabase and file specificationProgram design
Form the System SpecificationThe System Spec is given to the programming team for implementation
Slide 17
The system is actually built in this phaseUsually the longest phase
Implementation
Slide 18
Implementation
ConstructionNew system is built and testedOften testing is the longest part
Slide 19
Implementation
Conversion / InstallationOld system is turned offNew system is turned on
Three approachesCutover – immediate replacementParallel – both run for a whilePhased conversion – test group
Slide 20
Implementation
Conversion includes development of a Training Plan
How to use new systemManage change due to new system
Support PlanPost implementation reviewsHow to identify changed needed for the system
Slide 21
Processes and Deliverables
Process Product
Planning
Analysis
Design
Implementation
Project Plan
System Proposal
System Specification
New System and Maintenance
Plan
Slide 22
SYSTEM DEVELOPMENT Methodologies
Slide 23
What Is a Methodology?
A formalized approach or series of steps
A list of steps and deliverables
Writing code without a well-thought-out system request may work for small programs, but rarely works for large ones.
Slide 24
Structured Design
Projects move methodically from one to the next stepGenerally, a step is finished before the next one begins
Slide 25
Waterfall Development Method
Slide 26
Pros and Cons of the Waterfall Method
Pros Cons
Identifies systems requirements long before programming begins
Design must be specified on paper before programming begins
Long time between system proposal and delivery of new system
Rework is very hard
Parallel Development
Addresses problem of time gap between proposal and deliveryBreaks project into parallel subprojectIntegrates them at the end
Slide 27
Slide 28
Parallel Development
Slide 29
Alternatives to the SDLC
Rapid Application Development (RAD)Phased DevelopmentPrototypingThrow-Away Prototyping
Slide 30
Rapid Application Development
Critical elementsCASE toolsJAD sessionsFourth generation/visualization programming languagesCode generators
Slide 31
RAD: Phased Development
Break overall system into a series of versionsEach version has Analysis, Design, and ImplementationOutput from on version is the input to the nextIncorporate ideas, issues, lessons learned in one version into the next version
Slide 32
RAD: Phased Development
Pros Cons
Gets useful system to users quickly
Most important functions tested most
Initial system is intentionally incomplete
System requirements expand as users see versions
Slide 33
RAD: Prototyping
Analysis, Design, Implementation are performed concurrentlyStart with a "quick-and-dirty" prototype
Provides minimal functionality
Repeat process, refining the prototype each timeStop when prototype is a working system
Slide 34
RAD: Prototyping
Slide 35
RAD: Prototyping
Pros Cons
Gets working system to users quickly
Fast paced. Hard to conduct careful, methodical analysis
Reassures users that the project is progressing
Quickly refines true requirements
Initial design decisions have long term staying power
Problems may come to light late in design, requiring re-design
Slide 36
RAD: Throw-away prototyping
Use prototypes only to understand requirements
Example: use html to show UI
Prototype is not a working designOnce requirements are understood, the prototypes are thrown awayThe system is then built using SDLC
Slide 37
Throwaway Prototyping
Slide 38
Agile Development
Just a few rules that are easy to learn and followStreamline the SDLC
Eliminate much of the modeling and documentationEmphasize simple, iterative application development
Slide 39
Agile Development
Examples include:Extreme Programming (XP)ScrumDynamic Systems Development Model (DSDM)
Extreme Programming
“Core Values”Communication – All to AllSimplicity - KISSFeedback – Embrace ChangeCourage – Quality First
Slide 40
Extreme Programming
User StoriesCode small programUser FeedbackRepeatStandards are important
Naming conventionsCoding practices
Slide 41
Slide 42
Selecting the Appropriate Methodology
Clarity of User RequirementsFamiliarity with TechnologySystem ComplexitySystem ReliabilityShort Time SchedulesSchedule Visibility
Slide 43
Criteria for Selecting a Methodology
Slide 44
Project Team Roles and Skills
Slide 45
Information Systems Roles
Business analystSystem analystInfrastructure analystChange management analystProject manager
Slide 46
Business Analyst
Focuses on business issues surrounding the system
The business value of the systemImprovements in business processesNew business processes needed with new system
Requires business skills and professional training (e.g. CPA)
Slide 47
System Analyst
Focuses on IS issues How IS can improve business processesDesigns new information systemEnsures IS quality standards are maintained
Requires training & experience in design analysis, programming, business (to lesser degree)
Slide 48
Infrastructure Analyst
Focuses on interfaces between new system & existing infrastructure
Makes sure new system follows organizational standardsIdentifies required infrastructure changes
Requires experience in network & DB administrationRequires knowledge of HW systems
Slide 49
Change Management Analyst
Focuses on system installationDocumentation & support for usersCoordinate training of usersStrategies to overcome resistance
Requires experience in organizational behaviorRequires experience in change management
Slide 50
Project Manager
Responsible for schedule and budgetEnsures promised benefits are deliveredManages team membersResponsible for project plan and reporting progressRequires project management experience
Slide 51
Summary -- Part 1
The Systems Development Lifecycle consists of four stages: Planning, Analysis, Design, and ImplementationThe major development methodologies:
Structured design the waterfall method Parallel development
RAD development Prototyping (regular and throwaway)
Agile development XP streamline SDLC
Slide 52
Summary -- Part 2There are five major team roles:
Business analystSystems analystInfrastructure analystChange management analystProject manager.
