Chapter 1: The Object-Oriented Systems Development Environment

1. Chapter 1: The Object-Oriented Systems Development Environment Object-Oriented Systems Analysis and Design Joey F. George, Dinesh Batra, Joseph S. Valacich, Jeffrey A. Hoffer

2. Chapter Objectives • After studying this chapter you should be able to: • Define information systems analysis and design. • Explain the basics about systems. • Describe the information systems development cycle (SDC). • Describe TPS, MIS, and DSS. • Describe the role of systems analyst. • Recount the evolution of system development methodologies.

3. What Is Systems Analysis and Design? • Systems analysis and design is the process of analyzing user requirements, designinga solution to meet those needs, and ultimately building a software system that meets those needs and requirements. • Requires knowledge of: • The business objectives, structure, processes • Information technology opportunities and constraints

5. What Is a System? • A group of interrelated processes and procedures used for a business function, with an identifiable boundary, working together for some purpose. • A system has clear identifiable functional boundaries.Example a payroll system should not accept payments from outside customers. An email system should not create a spreadsheet

6. Characteristics of Systems • Input – data from environment to system • Output– data from system to environment • Components – objects or a subparts of systems operating independently • Interrelationships – associations between components of a system • Interfaces– mechanism for interacting with components • Boundary – identify the functionality limit of system

8. Important System Concepts • Decomposition – breaking down a system into smaller constituents • Modularity – the result of decomposition; parts of a system • Coupling – dependencies between subsystems • Cohesion – extent to which a subsystem performs a single function

9. Type Of Systems • TPS – Transaction Processing System.Increases efficiency and productivitya.k.a. OLTP (online transactional processing) • MIS – Management Information System.Converts data into information to help management optimize business decisions • DSS – Decision Support SystemInteractively assist with decision making.Allows for what-if scenarios & comparisons

11. Transaction Processing System (TPS) • Automate the handling of data for business activities or transactions • Also known as OLTP Online Transactional Processing system • Goal: improve transaction processing by increasing speed, enhancing productivity, simplifying processes

12. Management Information System (MIS) • Use raw data from TPS systems, and converts them into meaningful aggregate form. • Converts Data to Information • Goal: provide information to management to help them manage the business

13. Decision Support System (DSS) • Interactively assist with decision making by applying mathematical or logical models and a dialogue of interactions to solve unstructured problems (allow for what ifs) • Goal: provide comparisons of alternatives and recommendation of preferred option

14. The Four Steps of Systems Development Life Cycle • Systems Planning, Selection & Management • Systems Analysis • Systems Design • Systems Implementation, and Operations & Maintenance (Sometimes Operations & Maintenance is viewed as a separate 5th step.)

16. Systems Planning, Selection & Management • Analyze and arrange organization’s information needs, identify and describe potential project, determine system scope, and provide a business case for continuing with the project • Feasibility analysis: determine economic and organizational impact of the system • Management across all phases of development

17. Systems Analysis • Thorough study of organization’s current system and processes, determination of system requirements, structuring requirements, generate alternative design strategies. • Use of UML for system modeling • Goal: describe what needs to be done

18. Systems Design • Translating alternative solution generated by analysis phase into detailed logical and physical system specifications. • Logical design: not tied to any hardware or software platform. From the business view. • Physical design: specific programming languages, databases, architectures • Goal: identify how the task will be accomplished

19. System Implementation and Operation • Information system is coded, tested, and installed, and undergoes periodic corrections and enhancements • Goal: provide a fully operational system, and the continued success of the system

20. The Role of the Systems Analyst • Skills required: analytical, technical, managerial, interpersonal • Liaison between users, programmers, and other systems professionals

21. Evolution of System Development Methodologies • The output-Input based methodology - Examine the output will lead you to the requirements • Structured Analysis and Design - Use of Data Flow Diagrams to represent data movement • The System Development Life Cycle - System Planning, Analysis, Design & Implementation • Object Oriented Systems Analysis & Design - Iterative & incremental approach to systems development- Use of Unified Modeling Language (UML) Diagrams

23. The current trend is to use OOSAD, but many organizations are still using structured analysis and design

24. Object Oriented Systems Analysis & Design The best OO systems analysis & design methodology is RUP (Rational Unified Process). The methodology calls for a 4 phase approach: • Inception • Elaboration • Construction • Transition - Each phase is applied iteratively & incrementally - Each phase applies the same 4 SDLC steps

25. Inception Phase • Defining the scope, determining the feasibility, understanding user requirements, preparing a software development plan • Relatively short, low resource requirements • Focus on planning and initial analysis

26. Elaboration Phase • Detailed user requirements and baseline architecture is established • Fairly long, but not high in resource demand • Focus on detail analysis and design

27. Construction Phase • Coding, testing, and documenting code • Longest and most resource-intensive • Focus is on design and implementation

28. Transition Phase • System is deployed and users are trained and supported • Short-term, but resource-intensive • Focus is on installation, training, and support

29. Construction is the longest part

30. Iterative & Incremental A key feature of RUP is the iterative and incremental nature of the development process. • Iterative – means developing in pieces, and growing and improving each piece through successive iterations. • Incremental – means developing in pieces, and progressively adding new pieces through successive iterations.

31. RUP Phases across SDLC steps • Inception- mostly planning and analysis, low on design and implementation & operation. • Elaboration - high on planning, additional analysis, mostly design, low on implementation & operation. • Construction - high on planning, low on analysis, more design, mostly implementation & operations. • Transition – high on planning, low on analysis and design, high on implementation & operations.

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33. Recap • After studying this chapter we learned to: • Define information systems analysis and design. • Explain the basics about systems. • Describe the information systems development cycle (SDC). • Describe TPS, MIS, and DSS. • Describe the role of systems analyst. • Recount the evolution of system development methodologies.