Busi n ess Systems A nalysis and Design (IS330 1 )

1. Business Systems Analysisand Design (IS3301) 4 October, 2010 Models, Analysis Csaba Csáki Business Information Systems

2. Logistics • Lectures : 2 hours a week • Monday 4.00 - 5.00 pm, Kane G1 • Thursday 1.00 - 2.00 pm, GG LT • Lecturer : Csaba Csáki • Dept. Of Accounting, Finance and Information Systems – Business Information Systems • O’Rahilly Building, 3rd Floor, Room 3.77 • Tel: (021) 490 3835 • Email: C.Csaki@ucc.ie • Website: https://girtab.ucc.ie/ccsaki • Practical : 1 hour per student per week (DB w/ Access, Visio) • Thursday 10.00-11.00am (ORB b.05) A-K • Friday 1.00-2.00pm (ORB b.05) L-Z 3rd year BComm / 3301 / Business Systems Analysis and Design

3. Recap: Development mindset THE world (problem) Implementation SDLC reality Impl. model system (env.) requirements user requirements language feedback, test, QA its model code Use, maintenance feasibility Design /UI high level documentation (CLCA) Project management low level s/w 3rd year BComm / 3301 / Business Systems Analysis and Design

4. Recap: System Development Methodology Formal and precise process • Driving principles and a set of related techniques • Activities, methods, practices • E.g. to evaluate the costs and benefits of different solutions • Organized into a series of phases • Set of defined deliverables • A corresponding set of tools • Serving various participants and their needs • Project management tools • Modelling tools • Development management tools 3rd year BComm / 3301 / Business Systems Analysis and Design

5. Systems Development Life Cycle – Cross Life-Cycle Activities • How the phases organized into pragmatic stages • size of steps (deliverables) and activities executed • order of the stages • Different methodologies might follow (recommend) the same (type of) SDLC 2nd year BIS / 2211 / Business Modelling, Systems Analysis, Design & Change

6. Project management Quality Assurance Documentation SDLC & CLCA • Investigation/Initiation (planning) Stages Order of those stages (actual activities and deliverables also depend on methodology followed) • Analysis • Requirementsmodelling • Maintenance • Feedback • Improvement • Feasibility • High level design • logical • Detailed design • physical • Construction (implementation/development • Coding – Testing (!) – Documenting (!) • Installation (implementation at business) • (changeover, introduction, putting into use…) 2nd year BIS / 2211 / Business Modelling, Systems Analysis, Design & Change

7. SDLCs • Traditional • build-and-fix = lack of a lifecycle • Waterfall (7 phases) • Incremental • Iterative • Spiral • Recursive/parallel • OO (add responsibility) • Agile (no concise, accepted model) • Synchronize and stabilize (industrial) 2nd year BIS / 2211 / Business Modelling, Systems Analysis, Design & Change

8. A System Development Lifecycle 3rd year BComm / 3301 / Business Systems Analysis and Design

9. Spiral model of system development 3rd year BComm / 3301 / Business Systems Analysis and Design

10. Model • A Model is a simplified representation of a complex reality, usually for the purpose of understanding that reality, and having the features of that reality necessary for the current task or problem • Modelling is a form of abstraction -the process of focusing on those features that are essential for the task at hand and ignoring those that are not • Models are usually captured in the form of a diagram, thus a visual representation of the model 3rd year BComm / 3301 / Business Systems Analysis and Design

11. Logical vs. Physical models • Logical models show what a system is or does. They are implementation independent. • Physical models show not only what a system is or does, but also how the system is physically and technically implemented. 3rd year BComm / 3301 / Business Systems Analysis and Design

12. Definition : Analysis & Design • Analysis : what users need the system to do • Expressed through models • Depicted in diagrams • Design : how the system will meet the need 3rd year BComm / 3301 / Business Systems Analysis and Design

13. Project management Quality Assurance Documentaiton SDLC & CLCA • Investigation/Initiation (planning) Stages Order of those stages • Analysis • Requirements, Modelling • Maintenance • Feedback • Improvement • Feasibility • High level design • logical • Detailed design • physical • Construction (Implementation/development) • Coding – Testing (!) – Documenting (!) • Installation (implementation at business) • (changeover, introduction, putting into use…) 3rd year BComm / 3301 / Business Systems Analysis and Design

14. Analysis = listening Intimidated users => confusion 3rd year BComm / 3301 / Business Systems Analysis and Design

15. Doing it right • Do the right job effective • Do the job rightefficient • Do the job right on time professional 3rd year BComm / 3301 / Business Systems Analysis and Design

16. Analysis: Requirements • After system development initiation decision… • What are requirements? • Functional expectations • Performance expectations • Constraints • Environmental • System • Cultural • Regulatory (Basel II, SOX, …) 3rd year BComm / 3301 / Business Systems Analysis and Design

17. Modelling the requirements • Create the • Narrative • Context diagrams • Functional decomposition • Data and process models • Entity relationship model • Process specification • Data flow diagrams • Prioritize potential functionality • Activity diagram • Use cases • “Real world” objects 3rd year BComm / 3301 / Business Systems Analysis and Design

18. Narrative analysis rules • Look for who is doing something = Function • Mention of a department, person, responsibility • Eg. Once shipped by the shipping department • Look for action of what is being done = Process • Use of verbs (becomes, generates, requests, transfers, …) • Eg. Sales rep activities result in customer leads • Look for nouns (not people / geography) = Data • Leads, quotes orders, … • Eg. the order generates an invoice 3rd year BComm / 3301 / Business Systems Analysis and Design

19. Building a model • Functional decomposition • Context diagram • Data Flow Diagram • Context level • Processes • Data Flow • Data store • External entities 3rd year BComm / 3301 / Business Systems Analysis and Design

20. Functional Decomposition Diagram • Decomposition is the art of breaking a system into its component subsystems, processes, subprocesses. Each level of abstraction reveals more or less detail about the overall system or a subset of that system • a decomposition diagram shows the top-down functional decomposition and structure of a system 3rd year BComm / 3301 / Business Systems Analysis and Design

21. Functional decomposition 3rd year BComm / 3301 / Business Systems Analysis and Design

22. Context diagram • WHAT IS THE CONTEXT IN WHICH THE SYSTEM IS USED • THIS WILL IDENTIFY THE MAIN INTERNAL & EXTERNAL DIMENSIONS OF THE SYSTEM Global Airline seat booking On-line reservation system Internet Users 3rd year BComm / 3301 / Business Systems Analysis and Design

23. Context diagram Sales Order Process Sales Sales Order Processing Manufacturing Customers Shipping AR 3rd year BComm / 3301 / Business Systems Analysis and Design

24. DFDs and ERDs • Context level, level 1 and level 2 DFDs • Top-down and bottom-up ERDs • Theory of ERDs will be discussed during the following few lectures • Will learn details during lab tutorial sessions as well 3rd year BComm / 3301 / Business Systems Analysis and Design

25. Context level DFD Customer Provides travel details On-line reservation system Provides options Makes booking w/ payment 3rd year BComm / 3301 / Business Systems Analysis and Design