INFORMATION SYSTEMS DEVELOPMENT

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CHAPTER 8

• INFORMATION SYSTEMS DEVELOPMENT

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Participants in Systems Development

• Project planned collection of activities that
  achieves a goal
• Development team
• Stakeholders
• Users
• Managers
• Systems development specialists
• Support personnel

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Initiation of Systems Development

• Problems with existing systems
• Desire to exploit new opportunity
• Organizational growth
• Changes in the market or external environment
• Changes in organizational structure
• New laws and regulations

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Information Systems Planning
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Systems Development Life Cycle (SDLC)

• SDLC structured framework
• Consists of well-defined tasks
• Major phases
• Development activities
• After development activities

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A Five-Stage Systems Development Life Cycle (SDLC)
(1) Systems Investigation
(2) Systems Analysis
(3) Systems Design
(4) Implementation
(5) Maintenance
Go Back to a previous Stage or Stop
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Waterfall Approach

• Each step produces final outcome
• No loop back onto previous steps
• No modification during systems development

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Systems Investigation (Step 1)

• Determine the exact problem
• Feasibility Study
• technical feasibility
• economic feasibility
• legal feasibility
• operational feasibility
• schedule feasibility
• Deliverable systems investigation report

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Systems Analysis (Step 2)

• Assembling the participants for systems analysis
• Collecting appropriate data and requirements
• Analyzing the data and requirements
• Results in
• Strengths and weaknesses of the existing systems
• Functions of the new system
• User information requirements

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Data Collection

• Interviews
• Structured interviews
• Unstructured interviews
• Questionnaires
• Direct observation

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Data Analysis

• Data modeling
• ERD
• Activity modeling
• Data flow diagram
• Data flow lines
• Process symbols
• Entity symbols
• Data storage
• Application flow chart

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Entity-Relationship Diagram
PCode
SID
Since
Registers
Student
Program
Faculty
FCode
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Data Flow Diagram
Data for Schedule
Course Scheduling
Academic department
Offered Courses
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Systems Design (Step 3)

• IS outputs, inputs, and user interfaces
• Hardware, telecommunications, and procedures
• Software, databases
• Personnel
• How these components are integrated
• Two-step process
• Logical systems design main system components
• Physical systems design how the system
  components are accomplished

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Implementation (Step 5)
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Approaches to Implementation

• Parallel conversion
• Direct conversion
• Pilot conversion
• Phased conversion

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Maintenance and Review (Step 5)

• Operation
• Maintenance
• updating the system to accommodate changes in
  business conditions
• add new functionality to the system

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Alternatives to Conventional SDLC

• Rapid application development
• Prototyping
• Joint application design
• Object-oriented development
• End-user application development

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Prototyping
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Prototyping (cont)

• Prototype is built based on only a general idea
  of user requirements
• Advantages
• speeds up the development process
• gives users the opportunity to clarify their
  information requirements
• Disadvantages
• replaces the systematic analysis and design
  stages of the SDLC - quality may be sacrificed
• can result in an excess of iterations

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Joint Application Design (JAD)

• JAD is a group-based method for collecting user
  requirements
• Advantages
• saves time
• greater support for, and acceptance of new
  systems
• easier implementation
• lower training costs
• Disadvantages
• all the problems that may be caused by any group
  process

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Rapid Application Development (RAD)

• Combines JAD, prototyping and integrated CASE
  tools to produce a high-quality system rapidly
• RAD Packages
• GUI development environment
• Libraries of standard objects
• Code generators
• Integrated development environment to create
  computer codes

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Integrated Computer-Aided Software Engineering
(ICASE) Tools

• ICASE Tools automate many of the tasks in the
  SDLC
• CASE tools components
• Diagramming tools
• Analysis tools
• Repository tools
• Code generators

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Advantages of RAD

• speeds the development process
• reduces development costs
• can create applications that are easier to
  maintain and modify
• Disadvantages
• may result in systems with limited functionality
  and adaptability for change
• Not suitable for sophisticated calculations

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Object-Oriented Development

• OOD considers real-world systems as sets of
  interacting entities, which have attributes
• An entity is described as an object
• Methods (or operations) are used to change
  objects attributes (or data values)
• Object class incorporates similar objects
• Each object is considered as an instance of an
  object class
• Objects interact with each other by means of
  messages

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End-User Development

• Factors, which make it possible
• Increasing the power of desktop hardware
• Reducing hardware cost
• Increasing software capabilities
• Increasing computer-literate population
• Small and ad hoc applications
• Advantages
• Users get control over all stages of SDLC
• Saves time and money on application development

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Disadvantages of End-User Development

• Applications are simple
• More advanced hardware and software are required
• Leads to a large number of isolated applications
• Attracts time from main business duties
• Has limited area of application