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IS2210: Systems Analysis and Systems Design and Change

IS2210: Systems Analysis and Systems Design and Change. Email: cathal.doyle@umail.ucc.ie Twitter: @InstCathalDoyle Website: www.cathaldoyle.com. Tutorials. Location: O’Rahilly Building (ORB) B.05 Start Date: Thursday 10/10/2013 (bi-weekly) Time: 5-6pm. Last Week….

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IS2210: Systems Analysis and Systems Design and Change

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  1. IS2210: Systems Analysis and Systems Design and Change Email: cathal.doyle@umail.ucc.ie Twitter: @InstCathalDoyle Website: www.cathaldoyle.com

  2. Tutorials • Location: O’Rahilly Building (ORB) B.05 • Start Date: Thursday 10/10/2013 (bi-weekly) • Time: 5-6pm

  3. Last Week… • From todays lesson you should… • Understand what constitutes an information system • Know the major role of Information Systems (IS) • Understand Analysis and Design

  4. Questions • What is the difference between data and information? • What are the five components of an information systems? • What is the difference between analysis and design?

  5. Knowledge

  6. Learning Outcomes • From todays lecture you should: • Understand what SDLC is • Understand the five stages of SDLC • Understand the key deliverables of these five stages

  7. Why Systems Development? To correct problem in existing system To improve existing system Outside group may mandate change Competition can lead to change

  8. How It Can Go… • The next few slides are an exaggerated way systems development can go • However these are not unusual issues • How can we change that?

  9. “ Tree Swing – hanging from branch which people can sit and swing on” “Seat hanging from tree branches” “Swing from tree hanging from tree branches which people can sit on”

  10. Seat which hangs from a tree Comfortable and brilliant tree swing

  11. Obviously no documentation Only partial instalment Budgets overran Was it required?

  12. Customers may not fully know what they want. Important to ask the correct questions!! - Errors and omissions can be costly. Follow SDLC to ensure the correct steps are undertaken Communication Tyre Swing

  13. Guidelines for System Development • Arrange tasks into phases (groups of activities) • Involve users (anyone for whom the system is being built) • Develop clearly defined standards (procedures the company expects employees to follow)

  14. Systems Development Lifecycle (SDLC) • A process that can be applied to create, or alter information systems • Consists of different models and methodologies that people use to develop/alter IS • It can be seen as a very structured, and methodological way of developing IS

  15. Emergence of SDLC • Winston Boyce conceived SDLC as an aid to programming, with two stages of analysis and coding in 1970 • Further to this, Dr. Barry Boehm listed a number of the main phases of software development in 1974

  16. What It TRIES To Do… • It tries to ease the process of building a system • It tries to help reduce failures like unclear objectives, cost overruns, etc. • It tries to reduce the possibility of a system not meeting user needs

  17. SDLC Phases

  18. Phase 1: Planning • Initial phase of any SDLC • We initially would receive a request from the user for systems development • We do NOT just go and build it!!!

  19. Planning Stages: • Identify the problem to be solved by investigating the issue • Establish a team • Develop appropriate documentation • Project Charter (scope, objectives, participants) • Business Case • Project Feasibility (legally, technically, economically)

  20. Key Deliverables • General Problem Statement • Team members and roles • Feasibility Report

  21. Phase 2: Analysis • Analysis: System requirements are studied and structured • This is achieved by asking questions such as: • Why do problems exist? • Why were certain methods of work adopted? • Are there alternative methods?

  22. Analysis Stages: • Study and analyse the current system • System analysts collect facts from existing users • Existing systems limitations and details • Define new system objectives

  23. Define and Prioritise Users Requirements • The analyst approaches the users to find out what they want from the system • They use different data gathering techniques such as interviews, observations, and surveys • This is an attempt to understand all aspects of the current system and eventually indicate how things may be improved by a new system

  24. Key Deliverables • Formal requirements document (business requirements statement) • Data Flow Diagram (DFD) and Entity Relationship Diagram (ERD) of current system

  25. Phase 3: Design • System Design: Describes how the system will fulfill the user requirements • To achieve this, we must create both a logical design and physical design • Coding does not occur here!!!

  26. Design Stages: • Choosing an appropriate Database Management System (DBMS) • Establishing system security standards • Interface Design

  27. Data Capture Requirements • Standards for printed report production • System navigation methods

  28. What are possible solutions? Horizontal market software— meets needs of many companies Buypackaged software - prewritten software available for purchase Vertical market software — designed for particular industry Write own customsoftware – softwaredeveloped at user’s request Outsource – have outside source develop the software

  29. Key Deliverables • Functional Specification Document • data, processes, inputs, outputs, etc. • Technical Specification Document • programs, files, network, etc. • Implementation Schedule

  30. Phase 4: Implementation • We now need to convert our physical system specifications into a working and reliable solution • This is where we develop our system • This is followed by testing and then implementation

  31. Implementation Stages: • Coding • the physical design specifications are turned into working computer code • Integration and Testing • We create a testing environment where all our components are brought together • Installation • The new system is rolled out

  32. Key Deliverables • Fully Installed system • Fully trained users • User and Operational Documentation

  33. Phase 5: Maintenance • Occurs once the system is operational • Monitor system performance, and rectify bugs • Make requested changes

  34. Key Deliverables • Keep system live • Maintain code • Update software when required

  35. Overview of SDLC Establishes a high-level view of the intended project and determines its goals. • Software Changes are made here! Analyses end-user information needs in terms of what the IS should do. Describes desired features and operations in detail - how the parts of an information system should be implemented • Convert final physical system specifications into working and reliable software

  36. Questions • Q1: What is meant by SDLC? • Q2: What stage of the SDLC are requirements gathered and structured? • Q3: At what stage does coding take place?

  37. Thanks • Any questions?

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