1. Ch 3 System Development Environment
MIS 215 System Analysis
And Design
Ch 3 System Development Environment
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2. What is Information Systems Analysis and Design?
A method used by companies to create and maintain systems that perform basic business functions
Main goal is to improve employee efficiency by applying software solutions to key business tasks
A structured approach must be used in order to ensure success
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3. What is Information Systems Analysis and Design? (Cont.)
Systems Analysts perform analysis and design based upon:
Understanding of organization’s objectives, structure and processes
Knowledge of how to exploit information technology for advantage
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4. Systems Analysis and Design: Core Concepts
Major goal: to improve organizational systems by developing or acquiring application software and training employees in its use
Application software, or a system, supports organizational functions or processes
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5. Systems Analysis and Design: Core Concepts (Cont.)
Turns data into information and includes:
Hardware and system software
Documentation and training materials
Job roles associated with the system
Controls to prevent theft or fraud
The people who use the software to perform their jobs
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6. Software Engineering Process
A process used to create an information system
Consists of:
Methodologies
A sequence of step-by-step approaches that help develop the information system
Techniques
Processes that the analyst follows to ensure thorough, complete, and comprehensive analysis and design
Tools
Computer programs that aid in applying techniques
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8. Characteristics of a System
Components
Interrelated Components
Boundary
Purpose
Environment
Interfaces
Constraints
Input
Output
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9. Characteristics of a System
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10. Important System Concepts
Decomposition
The process of breaking down a system into smaller components
Allows the systems analyst to:
Break a system into small, manageable and understandable subsystems
Focus on one area at a time, without interference from other areas
Concentrate on component pertinent to one group of users without confusing users with unnecessary details
Build different components at independent times and have the help of different analysts
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11. Important System Concepts (Cont.)
Modularity
Process of dividing a system into modules of a relatively uniform size
Modules simplify system design
Coupling
Subsystems that are dependent upon each other are coupled
Cohesion
Extent to which a subsystem performs a single function
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12. A Modern Approach to Systems Analysis and Design
Systems Integration
Allows hardware and software from different vendors to work together
Enables procedural language systems to work with visual programming systems
Visual programming environment uses client/server model
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13. Your Role in Systems Development
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 their requirements for new or enhanced information systems
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14. Our Approach to Systems Development
The SDLC is an organizing and guiding principle in this book.
We may construct artificial boundaries or artificially separate activities and processes for learning purposes.
Our intent is to help you understand all the pieces and how to assemble them.
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15. Systems Development Life Cycle (SDLC)
Traditional methodology used to develop, maintain, and replace information systems.
Phases in SDLC:
Planning
Analysis
Design
Implementation
Maintenance
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16. Systems Development Life Cycle (SDLC) (Cont.)
Planning – an organization’s total information system needs are identified, analyzed, prioritized, and arranged
Analysis – system requirements are studied and structured
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17. Systems Development Life Cycle (SDLC) (Cont.)
Design – a description of the recommended solution is converted into logical and then physical system specifications
Logical design – all functional features of the system chosen for development in analysis are described independently of any computer platform
Physical design – the logical specifications of the system from logical design are transformed into the technology-specific details from which all programming and system construction can be accomplished
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18. Systems Development Life Cycle (SDLC) (Cont.)
Implementation – the information system is coded, tested, installed and supported in the organization
Maintenance – an information system is systematically repaired and improved
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20. Traditional Waterfall SDLC
One phase begins when another completes, with little backtracking and looping.
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21. Problems with Waterfall Approach
System requirements “locked in” after being determined (can't change)
Limited user involvement (only in requirements phase)
Too much focus on milestone deadlines of SDLC phases to the detriment of sound development practices
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22. Approaches to Development
Prototyping
Building a scaled-down working version of the system
Advantages:
Users are involved in design
Captures requirements in concrete form
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23. Different Approaches to Improving Development
CASE Tools
Rapid Application Development (RAD)
Agile Methodologies
eXtreme Programming
Joint Application Design (JAD)
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24. CASE Computer-Assisted Software Engineering (CASE) Tools
Automated software tools used by systems analysts to develop information systems
Can be used throughout SDLC
Product and tool integration is provided through a repository
Diagramming tools enable graphical representation.
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25. CASE (Cont.) General types of CASE tools Diagramming tools
Computer display and report generators
Analysis tools
Repository
Documentation generators
Code generators
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26. CASE (Cont.) Computer-Assisted Software Engineering (CASE) Tools:
Computer displays and report generators help prototype how systems “look and feel”.
Analysis tools automatically check for consistency in diagrams, forms, and reports.
A central repository provides integrated storage of diagrams, reports, and project management specifications.
Documentation generators standardize technical and user documentation.
Code generators enable automatic generation of programs and database code directly from design documents, diagrams, forms, and reports.
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27. CASE Tools (Cont.)
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28. CASE Tools (Cont.)
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29. Approaches to Development (Cont.)
Joint Application Design (JAD)
Users, Managers and Analysts work together for several days
System requirements are reviewed
Structured meetings
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30. Rapid Application Development (RAD)
Utilizes prototyping to delay producing system design until after user requirements are clear
Methodology to radically decrease design and implementation time
Involves: extensive user involvement, prototyping, JAD sessions, integrated CASE tools, and code generators
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31. RAD (Cont.)
RAD life cycle
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32. Service-Oriented Architecture (SOA)
An approach to systems development based on building complete systems through assembling software components, each of which model generic business functions
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33. Service-Oriented Architecture (SOA) (Cont.)
Illustration of a service, a credit check,
used by applications and other services
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34. Agile Methodologies
Motivated by recognition of software development as fluid, unpredictable, and dynamic
Three key principles
Adaptive rather than predictive
Emphasize people rather than roles
Self-adaptive processes
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35. When to use Agile Methodologies
If your project involves:
Unpredictable or dynamic requirements
Responsible and motivated developers
Customers who understand the process and will get involved
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37. eXtreme Programming Short, incremental development cycles
Automated tests
Two-person programming teams
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38. eXtreme Programming (Cont.)
Coding and testing operate together
Advantages:
Communication between developers
High level of productivity
High-quality code
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39. Object-Oriented Analysis and Design (OOAD)
Based on objects rather than data or processes
Object: a structure encapsulating attributes and behaviors of a real-world entity
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40. Object-Oriented Analysis and Design (OOAD) (Cont.)
Object class: a logical grouping of objects sharing the same attributes and behaviors
Inheritance: hierarchical arrangement of classes enable subclasses to inherit properties of superclasses
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41. Rational Unified Process (RUP)
An object-oriented systems development methodology
RUP establishes four phase of development: inception, elaboration, construction, and transition.
Each phase is organized into a number of separate iterations.
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42. Phases of OOSAD-based development
FIGURE 1-13
Phases of OOSAD-based development
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43. Summary Define information systems analysis and design.
In this chapter you learned how to:
Define information systems analysis and design.
Describe the information Systems Development Life Cycle (SDLC).
Explain Rapid Application Development (RAD), prototyping, Computer Aided Software Engineering (CASE), and Service-Oriented Architecture (SOA).
Describe agile methodologies and eXtreme programming.
Explain Object Oriented Analysis and Design and the Rational Unified Process (RUP).
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