An Introduction to Object-Oriented Systems Analysis and Design with UML and the Unified Process McGraw-Hill, 2004 Step

1. An Introduction toObject-Oriented Systems Analysis and Design with UML and the Unified ProcessMcGraw-Hill, 2004Stephen R. Schachsrs@vuse.vanderbilt.edu

2. CHAPTER 1 INTRODUCTION TO INFORMATION SYSTEMS

3. Chapter Overview • Categories of Information Systems • Traditional Information System Development • The Requirements Phase • The Analysis Phase • The Design Phase • The Implementation Phase • The Maintenance Phase • Retirement

4. Chapter Overview (contd) • Why There Is No Planning Phase • Why There Is No Testing Phase • Why There Is No Documentation Phase • Systems Analysis and Design • Maintenance • Information Technology Professionals

5. Jethro’s Boot Emporium • Automated reordering system • Jethro’s formula for predicting future trends • The formula works perfectly … • … at first

6. Definitions • Artifact • Component • System • Set of artifacts that achieve some outcome • Information system • System that achieves a business outcome • Computerized information system • COTS (commercial off-the-shelf) package • Custom information system

7. Custom Information System • Stakeholders • Client • Users • Developers

8. COTS Software • Shrinkware • Clickware • Stakeholders • Users • Developers • Enterprise Resource Planning (ERP) system • Examples: PeopleSoft, SAP

9. Traditional Information System Development • Information system life cycle • The way that software is constructed • Six traditional phases

10. Overview of the Traditional Phases • Requirements phase • Find the client’s requirements • Draw up the requirements document • Analysis phase • Draw up the specification document • Draw up the project management plan • Design phase • Determine the modules • Determine algorithms and data structures for each module

11. Overview of the Traditional Phases (contd) • Implementation phase • Translate the modules into a programming language • Integrate the modules • Maintenance phase • Modify the system • Remove any remaining faults • Extend the system in some way • Retirement • The system no longer provides a useful service

12. Why There Is No Planning Phase • We cannot plan until we have accurate, detailed information • There are three types of planning activities: • There is preliminary planning at the start of the project • The project management plan is drawn up after the specifications have been approved by the client • Management monitor the plan all through the project

13. Why There Is No Planning Phase (contd) • Planning activities are carried out all through the life cycle  There is no separate planning phase

14. Why There is No Testing Phase • Checking the information system just before delivery is much too late • An information system must be checked continually  There is no separate testing phase

15. Why There Is No Documentation Phase • The documentation must be complete, correct, and up to date at all times • Personnel turnover in the information system industry • Performing a phase requires the documentation from the previous phase • Testing activities require documentation • Maintenance activities require documentation  There is no separate documentation phase

16. Systems Analysis and Design • The word analysis is used in two different ways: • Analysis: Phase 2 • Systems analysis: Phases 1 and 2 • The term systems analyst is also used in two different ways • Responsible for Phases 1 and 2; or • Responsible for Phases 1, 2, and 3 • The second usage is more common • That is the way systems analyst is used in this book

17. Maintenance • Bad information systems are thrown away • Good information systems are maintained for many years

18. The Financial Implications of Maintenance • For very $1 spent on development, at least $2 is spent on maintenance

19. Maintenance Activities • There are three main maintenance activities: • Corrective maintenance • Fixing faults • Perfective maintenance • Adding functionality • Adoptive maintenance • Making changes because the environment changes • (Enhancement: Corrective + Perfective maintenance)

20. Software Organizations • Software • Computer program (code) + documentation • Many organizations produce software • They employ systems analysts • Some organizations outsource

21. Software Organizations • Organizations like Microsoft and Oracle produce software • As a primary product • Organization like General Motors and General Electric produce software • But not as a primary product

22. Typical Information Systems Division

23. Information Technology Professionals • Technical positions • Programmer • Programmer/analyst • Systems analyst • Alternative career path • Business analyst • Acquire programming skills  Systems analyst

24. Information Technology Professionals (contd) • Management hierarchy • Manager for information system development • Vice-President for information system development • Chief information officer (CIO) • Chief executive officer (CEO)

25. Essential Systems Analyst Skills • Technical skills • Communication skills • Programming knowledge • Sufficient technical knowledge to able to consult • Database administrator • Network administrator • Systems programmers • Software engineers

26. Ethical Issues • Systems analysts must be ethical in every way • Example: Excerpt from the Code of Ethics of AITP “I acknowledge: That I have an obligation to my College or University, therefore, I shall uphold its ethical and moral principles. That I have an obligation to my employer whose trust I hold, therefore, I shall endeavor to discharge this obligation to the best of my ability, to guard my employer's interests, and to advise him or her wisely and honestly. I accept these obligations as a personal responsibility and as a member of this Association. I shall actively discharge these obligations and I dedicate myself to that end.”