System Analysis and Design

23,018 views

Published on

Unit II SAD

Published in: Education, Technology, Business
7 Comments
43 Likes
Statistics
Notes
No Downloads
Views
Total views
23,018
On SlideShare
0
From Embeds
0
Number of Embeds
1,719
Actions
Shares
0
Downloads
83
Comments
7
Likes
43
Embeds 0
No embeds

No notes for slide

System Analysis and Design

  1. 1. Systems Analysis and Design
  2. 2. Key Ideas <ul><li>Many failed systems were abandoned because analysts tried to build wonderful systems without understanding the organization. </li></ul><ul><li>The primarily goal is to create value for the organization. </li></ul>
  3. 3. Key Ideas <ul><li>The systems analyst is a key person analyzing the business, identifying opportunities for improvement, and designing information systems to implement these ideas. </li></ul><ul><li>It is important to understand and develop through practice the skills needed to successfully design and implement new information systems. </li></ul>
  4. 4. THE SYSTEMS DEVELOPMENT LIFE CYCLE
  5. 5. Major Attributes of the Life Cycle <ul><li>The project -- </li></ul><ul><ul><li>Moves systematically through phases where each phase has a standard set of outputs </li></ul></ul><ul><ul><li>Produces project deliverables </li></ul></ul><ul><ul><li>Uses deliverables in implementation </li></ul></ul><ul><ul><li>Results in actual information system </li></ul></ul><ul><ul><li>Uses gradual refinement </li></ul></ul>
  6. 6. Project Phases <ul><li>Planning (Why build the system? How should the team go about building it?) </li></ul><ul><li>Analysis (Who uses system, what will it do, where and when will the system be used?) </li></ul><ul><li>Design (How will the system work?) </li></ul><ul><li>Implementation (System delivery) </li></ul>
  7. 7. A simple process for making lunch
  8. 8. <ul><li>Identifying business value </li></ul><ul><li>Analyze feasibility </li></ul><ul><li>Develop work plan </li></ul><ul><li>Staff the project </li></ul><ul><li>Control and direct project </li></ul>Planning
  9. 9. <ul><li>Analysis strategy </li></ul><ul><li>Gathering business requirements </li></ul><ul><li>Requirements definition use cases </li></ul><ul><li>Process modeling </li></ul><ul><li>Data modeling </li></ul>Analysis
  10. 10. <ul><li>Design selection </li></ul><ul><li>Architecture design </li></ul><ul><li>Interface design </li></ul><ul><li>Data storage design </li></ul><ul><li>Program design </li></ul>Design
  11. 11. <ul><li>Construction </li></ul><ul><ul><li>Program building </li></ul></ul><ul><ul><li>Program and system testing </li></ul></ul><ul><li>Installation </li></ul><ul><ul><li>Conversion strategy </li></ul></ul><ul><ul><li>Training plan </li></ul></ul><ul><ul><li>Support plan </li></ul></ul>Implementation
  12. 12. Processes and Deliverables Process Product Planning Analysis Design Implementation System Request Feasibility Analysis Workplan System Proposal System Specification New System and Maintenance Plan
  13. 13. SYSTEM DEVELOPMENT METHODOLOGIES
  14. 14. What Is a Methodology? <ul><li>A formalized approach to implementing the SDLC </li></ul><ul><ul><li>A series of steps and deliverables </li></ul></ul><ul><li>Methodology Categories </li></ul><ul><li>Process-Centered </li></ul><ul><li>Data-Centered </li></ul><ul><li>Object-Oriented </li></ul><ul><li>Structured Design </li></ul><ul><li>Rapid Application Development </li></ul><ul><li>Agile Development </li></ul>
  15. 15. Waterfall Development Methodology
  16. 16. Pros and Cons of the Waterfall Methodology Pros Cons Identifies systems requirements long before programming begins Minimizes changes to requirements as project progresses Design must be specified on paper before programming begins Long time between system proposal and delivery of new system
  17. 17. Parallel Development Methodology
  18. 18. Pros and Cons of Parallel Development Methodology Pros Cons Reduces Schedule Time Less Chance of Rework Still Uses Paper Documents Sub-projects May Be Difficult to Integrate
  19. 19. Rapid Application Development <ul><li>Incorporate special techniques and tools: </li></ul><ul><ul><li>CASE tools </li></ul></ul><ul><ul><li>JAD sessions </li></ul></ul><ul><ul><li>Fourth generation/visualization programming languages </li></ul></ul><ul><ul><li>Code generators </li></ul></ul>
  20. 20. Three RAD Categories <ul><li>Phased development </li></ul><ul><ul><li>A series of versions developed sequentially </li></ul></ul><ul><li>Prototyping </li></ul><ul><ul><li>System prototyping </li></ul></ul><ul><li>Throw-away prototyping </li></ul><ul><ul><li>Design prototyping </li></ul></ul>
  21. 21. Phased Development Methodology Insert Figure 1-4 here
  22. 22. Pros and Cons of Phased Development Methodology Pros Cons Users Get a System To Use Quickly Users Can Identify Additional Needs For Later Versions Users Work with a System that is Intentionally Incomplete
  23. 23. How Prototyping Works
  24. 24. Pros and Cons of Prototyping Methodology Pros Cons Users Interact with Prototype Very Quickly Users Can Identify Needed Changes And Refine Real Requirements Tendency to do Superficial Analysis Initial Design Decisions May Be Poor
  25. 25. Throwaway Prototyping
  26. 26. Pros and Cons of Throwaway Prototyping Methodology Pros Cons Risks are Minimized Important Issues are Understood Before the Real System is Built May Take Longer Than Prototyping
  27. 27. Agile Development: Extreme Programming
  28. 28. Pros and Cons of Agile Methodologies Pros Cons Fast Delivery of Results Works Well in Projects With Undefined or Changing Requirements Requires Discipline Works Best in Small Projects Requires Much User Input
  29. 29. Criteria for Selecting the Appropriate Methodology <ul><li>Clear user requirements </li></ul><ul><li>Familiarity with technology </li></ul><ul><li>Complexity of system </li></ul><ul><li>Reliability of system </li></ul><ul><li>Time schedule </li></ul><ul><li>Schedule visibility </li></ul>
  30. 30. TEAM ROLES AND SKILLS
  31. 31. Information Systems Roles <ul><li>Business analyst </li></ul><ul><li>Systems analyst </li></ul><ul><li>Infrastructure analyst </li></ul><ul><li>Change management analyst </li></ul><ul><li>Project manager </li></ul>
  32. 32. Summary <ul><li>The Systems Development Lifecycle consists of four stages: Planning, Analysis, Design, and Implementation </li></ul><ul><li>There are six major development methodologies : the waterfall method, the parallel development method, the phased development method, system prototyping, design prototyping, and agile development. </li></ul><ul><li>There are five major team roles : business analyst, systems analyst, infrastructure analyst, change management analyst and project manager. </li></ul>

×