Chapter 1 The ObjectOriented Systems Development Environment ObjectOriented
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 © Prentice Hall, 2004 1 -1
Chapter Objectives l 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. Chapter 1 © Prentice Hall, 2004 2
What Is Systems Analysis and Design? l The process of implementing and operating an information system l Requires knowledge of: – Organization’s objectives, structure, processes – Information technology opportunities and constraints Chapter 1 © Prentice Hall, 2004 3
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What Is a System? l A group of interrelated procedures used for a business function, with an identifiable boundary, working together for some purpose. Chapter 1 © Prentice Hall, 2004 5
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Characteristics of Systems l Boundary – divides system from environment l Inputs – data from environment to system l Output – data from system to environment l Components – subparts of systems operating independently (objects) l Interrelationships – associations between components of a system l Interfaces – mechanism for interacting with a component Chapter 1 © Prentice Hall, 2004 7
Important System Concepts l Decomposition – breaking down a system into smaller constituents l Modularity – the result of decomposition; parts of a system l Coupling – dependencies between subsystems l Cohesion – extent to which a subsystem performs a single function Chapter 1 © Prentice Hall, 2004 8
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Transaction Processing System (TPS) l Automate the handling of data for business activities or transactions l Goal: improve transaction processing by increasing speed, enhancing productivity, simplifying processes Chapter 1 © Prentice Hall, 2004 10
Management Information System (MIS) l Use raw data from TPS systems, and converts them into meaningful aggregate form l Goal: provide the information that helps managers in their jobs Chapter 1 © Prentice Hall, 2004 11
Decision Support System (DSS) l Interactively assist with decision making by applying mathematical or logical models and a dialogue of interactions to solve unstructured problems l Goal: provide comparisons of alternatives and recommendation of preferred option Chapter 1 © Prentice Hall, 2004 12
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The Role of the Systems Analyst l Skills required: analytical, technical, managerial, interpersonal l Liaison between users, programmers, and other systems professionals Chapter 1 © Prentice Hall, 2004 14
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Systems Planning and Selection l 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 l Feasibility analysis: determine economic and organizational impact of the system Chapter 1 © Prentice Hall, 2004 18
Systems Analysis l Thorough study of organization’s current system and processes, determination of system requirements, structuring requirements, generate alternative design strategies. l Use of UML for system modeling l Goal: describe what needs to be done Chapter 1 © Prentice Hall, 2004 19
Systems Design l Translating alternative solution generated by analysis phase into detailed logical and physical system specifications. – Logical design: not tied to any hardware or software platform – Physical design: specific programming languages, databases, architectures l Goal: identify how the task will be accomplished Chapter 1 © Prentice Hall, 2004 20
System Implementation and Operation l Information system is coded, tested, and installed, and undergoes periodic corrections and enhancements l Goal: provide a fully operational system Chapter 1 © Prentice Hall, 2004 21
Evolution of System Development Methodologies l SDLC – Systems Development Life Cycle l Structured Analysis and Design – Use of Data Flow Diagrams l Data-Oriented Methodology – Use of Entity Relation Diagrams l Object-Oriented Methodology – Use of Unified Modeling Language (UML) Diagrams Chapter 1 © Prentice Hall, 2004 22
The current trend is to use OOSAD, but many organizations are still using structured analysis and design Chapter 1 © Prentice Hall, 2004 23
Inception l Defining the scope, determining the feasibility, understanding user requirements, preparing a software development plan l Relatively short, low resource requirements l Focus on planning and analysis Chapter 1 © Prentice Hall, 2004 24
Elaboration l Detailed user requirements and baseline architecture is established l Fairly long, but not high in resource demand l Focus on analysis and design Chapter 1 © Prentice Hall, 2004 25
Construction l Coding, testing, and documenting code l Longest and most resource-intensive l Focus is on implementation tasks Chapter 1 © Prentice Hall, 2004 26
Transition l System is deployed and users are trained and supported l Short-term, but resource-intensive l Focus is on installation, training, and support Chapter 1 © Prentice Hall, 2004 27
Construction is the hardest part Chapter 1 © Prentice Hall, 2004 28
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Recap l 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. Chapter 1 © Prentice Hall, 2004 30
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