Introduction to Business Systems Development

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Introduction to Business Systems Development
BCO1048
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VU Day 3 Topic 3
INFORMATION SYSTEM DEVELOPMENT
Satzinger 4th ed. Chapter 2
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Information System Development

• Overview
• Differentiate between the system life cycle and a
  system development methodology.
• Explain the purpose and various phases of the
  systems development lifecycle (SDLC)
• Describe eight basic principles of system
  development.
• Define problems, opportunities, and
  directivesthe triggers for systems development
  projects.
• Describe a framework for categorising problems,
  opportunities, and directives.
• Describe the traditional, basic phases of system
  development. For each phase, describe its
  purpose, inputs, and outputs.
• Describe cross life cycle activities that overlap
  all system development phases.

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System Development Process

• A system development process is a set of
  activities, methods, best practices,
  deliverables, and automated tools that
  stakeholders use to develop and maintain
  information systems and software.
• This process is called the System Development
  Life Cycle (SDLC) because every IS system is
  born and eventually dies.

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Designing Systems

• Information is a valuable resource that needs to
  be managed and not wasted.
• Systems are complex
• easy to miss key details
• Ad Hoc methods frequently fail to meet
  requirements.
• Need to improve chance of developing a successful
  system
• Any model of a solution is better than no model
• Companies do change, so systems change

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System Development Life Cycles and Methodologies

• The process followed to develop information
  systems is called a methodology
• A system development life cycle (SDLC) is a
  logical method of system development

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A methodology is the physical implementation of
that logical life cycle including (1)
step-by-step activities for each phase (2)
individual /group roles to be played in each
activity (3) deliverables and quality
standards for each activity (4) tools and
techniques to be used for each activity
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Why do we use Methodologies?

• ensure that a consistent, reproducible approach
  is applied to all projects systematic approach
• reduce the risk associated with shortcuts and
  mistakes
• produce complete and consistent documentation
  from one project to the next
• able to incorporate the use of several
  development tools and techniques

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Principles of Systems Development
1 Get the Owners and Users Involved 2 Use a
Problem-Solving Approach 3 Establish Phases
and Activities 4 Establish standards for
consistent development and documentation 5
Justify systems as capital investments 6
Cancel project or revise scope if necessary 7
Divide and conquer 8 Design systems for growth
and change
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Life Cycle versus Methodology

• A system life cycle divides the life of an
  information system into stages systems
  development and systems operation and support.

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Life Cycle versus Methodology

• A system development methodology
• is a very formal and precise system development
  process
• defines a set of activities, methods, best
  practices, deliverables, and automated tools
• for system developers and project managers to use
  to develop and maintain information systems and
  software.

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A System Life Cycle
Whitten et al Fig 3.2
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System Development Life Cycle (SDLC)

• Systems development project
• Planned undertaking
• Large and complex job
• Produces new system
• Successful project requirements
• Detailed plans
• Organised, methodical sequence of tasks and
  activities

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Systems Development Lifecycle (SDLC)

• Three major activities
• Analysis understanding business needs
• Design conceptualizing computer-system solution
• Implementation construction, testing, and
  installation
• Two additional phases
• Project planning (early)
• Support (after implementation)

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IS Development Phases
Satzinger et al. (2006) Figure 2-2
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SDLC Concepts

• All projects use some variation of the SDLC
• SDLC is more than phases
• Principles of management
• Planning and control
• Organization and scheduling
• Problem solving

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Planning Phase

• Define problem
• Confirm project feasibility
• Produce project schedule
• Staff the project
• Launch the project

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Analysis Phase

• Gather information
• Define system requirements
• Build prototypes for discovery of requirements
• Prioritize requirements
• Generate and evaluate alternatives
• Review recommendations with management

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Design Phase

• Design and integrate the network
• Design the application architecture
• Design the user interfaces
• Design the system interfaces
• Design and integrate the database
• Prototype for design details
• Design and integrate the system controls

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Implementation Phase

• Construct software components
• Verify and test
• Convert data
• Train users and document the system
• Install the system

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Support Phase

• Maintain the system
• Enhance the system
• Support the users
• Help desk

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Fig. 2-20 Life cycles with different names for
phases
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Scheduling of Project Phases

• Considerations
• Migration from waterfall approach to overlapping
  and concurrent phases
• Efficiency
• Dependency
• Iteration
• Ripple effect

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Overlap of Systems Development Activities
Satzinger et al. (2006) Figure 2-5
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Overlap of System Development Phases
Whitten et al Fig 3.4
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Project Identification Initiation

• Problems are undesirable situations that prevent
  the organisation from fully achieving its
  purpose, goals, and/or objectives
• Opportunities are chances to improve the
  organisation even in the absence of specific
  problems
• Directives are new requirements that are imposed
  by management, government, or some external
  influence

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Typical Development Phases
Whitten et al Fig 3.5
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Cross Life Cycle Activities

• Cross life cycle activities are activities that
  overlap many or all phases of the methodology.
• Fact-finding
• Documentation and presentation
• Feasibility analysis
• Process and project management

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Iteration Across Life Cycle Phases
Satzinger et al (2006) Fig 2-7
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A Repository
A repository is a database where system
developers store all documentation, knowledge,
and products for one or more information systems
or projects.
Whitten et al Fig 3.7
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Alternative Routes through a Methodology

• Model-Driven Development (MDD)
• Rapid Application Development (RAD)
• Commercial Off-the-Shelf Software
• Maintenance and Reengineering or hybrids of the
  above

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Model-Driven Development

• Modelling is the act of drawing one or more
  graphical representations (or pictures) of a
  system
• Modelling is a communication technique based upon
  the old saying
• a picture is worth a thousand words

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Model-Driven Development

• Model-driven development techniques emphasize the
  drawing of models to help visualize and analyse
  problems, define business requirements, and
  design information systems.
• Structured systems analysis and design
  process-centered
• Information engineering (IE) data-centered
• Object-oriented analysis and design (OOAD)
  object-centered (integration of data and process
  concerns)

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Model-Driven Development (MDD)
Whitten et al Fig 3.8
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Rapid Application Development

• Rapid application development (RAD) techniques
  emphasize extensive user involvement in the rapid
  and evolutionary construction of working
  prototypes of a system to accelerate the system
  development process.

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Rapid Application Development

• RAD is based on building prototypes that evolve
  into finished systems (often using time boxing)
• A time box is a non-extendable period of time,
  usually 60-120 days, by which a candidate system
  must be placed into operation

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Rapid Application Development (RAD)
Whitten et al Fig 3.9
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Prototyping

• Prototyping is a technique used to develop a
  smaller-scale, representative or working model of
  the users requirements or a proposed design for
  an information system.
• When extended to system design and construction,
  a prototype can evolve into the final,
  implemented system

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Commercial Off-the-Shelf Software

• Commercial off-the-shelf software is a software
  package or solution that is purchased to support
  one or more business functions and information
  systems

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Commercial Off-the-Shelf Software
Whitten et al Fig 3.10
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Hybrid Rapid Architected Development
Whitten et al Fig 3.11
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Maintenance and Reengineering
Whitten et al Fig 3.12
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Reference for ITIL

• In Application Management, they use the Systems
  Development Life Cycle, which is just a specific
  project methodology for IT application projects.
  It's how you get some commonality across the
  deployments in your data centre between the
  people who write code and the people who are
  doing Service improvement.
• You use a generic process framework that can fit
  in nicely with ITIL to help an organisation
  deliver IT better. PRINCE/2 is a project
  framework to control the development process for
  anything that's not a Business As Usual activity.
  It also scales really well from tiny to giant
  projects.

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Homework

• From Satzinger et al.
• Read and summarize Chapter 2 p.35-50
• Complete
• Review Questions 1,3, 4,5,7,12,16,19,20 (page
  69)
• Experiential Exercises 2 page 70