Cis520 ch01
- 1. Modern Systems Analysis and Design Prof. David Gadish Chapter 1 The Systems Development Environment
- 2. Learning Objectives ü Define information systems analysis and design. ü Describe the different types of information systems. ü Describe the information Systems Development Life Cycle (SDLC). ü Explain Rapid Application Development (RAD), prototyping, Joint Application Development (JAD), and Computer Aided Software Engineering (CASE). ü Describe agile methodologies and eXtreme programming. ü Explain Object Oriented Analysis and Design and the Rational Unified Process (RUP). Chapter 1 2
- 3. Introduction n Information Systems Analysis and Design ¨ Complex organizational process. ¨ Used to develop and maintain computer based information systems. ¨ Used by a team of business and systems professionals. Chapter 1 3
- 4. Introduction (Cont.) Figure 11 An organizational approach to systems analysis and design is driven by methodologies, techniques, and tools Chapter 1 4
- 5. A Modern Approach to Systems Analysis and Design n 1950s: focus on efficient automation of existing processes n 1960s: advent of 3GL, faster and more reliable computers n 1970s: system development becomes more like an engineering discipline Chapter 1 5
- 6. A Modern Approach to Systems Analysis and Design (Cont.) n 1980s: major breakthrough with 4GL, CASE tools, object oriented methods n 1990s: focus on system integration, GUI applications, client/server platforms, Internet n The new century: Web application development, wireless PDAs, component based applications Chapter 1 6
- 7. A Modern Approach to Systems Analysis and Design (Cont.) n Application Software ¨ Computer software designed to support organizational functions or processes. n Systems Analyst ¨ Organizational role most responsible for analysis and design of information systems. Chapter 1 7
- 9. Types of Information Systems and Systems Development n Transaction Processing Systems (TPS) ¨ Automate handling of data about business activities (transactions) ¨ Process orientation n Management Information Systems (MIS) ¨ Converts raw data from transaction processing system into meaningful form ¨ Data orientation Chapter 1 9
- 10. Types of Information Systems and Systems Development (Cont.) n Decision Support Systems (DSS) ¨ Designed to help decision makers ¨ Provides interactive environment for decision making ¨ Involves data warehouses, executive information systems (EIS) ¨ Database, model base, user dialogue Chapter 1 10
- 12. Developing Information Systems n System Development Methodology is a standard process followed in an organization to conduct all the steps necessary to analyze, design, implement, and maintain information systems. Chapter 1 12
- 13. Systems Development Life Cycle (SDLC) n Traditional methodology used to develop, maintain, and replace information systems. n Phases in SDLC: ¨ Planning ¨ Analysis ¨ Design ¨ Implementation ¨ Maintenance Chapter 1 13
- 15. Systems Development Life Cycle (SDLC) (Cont.) n Planning – an organization’s total information system needs are identified, analyzed, prioritized, and arranged. n Analysis – system requirements are studied and structured. Chapter 1 15
- 16. Systems Development Life Cycle (SDLC) (Cont.) n Design – a description of the recommended solution is converted into logical and then physical system specifications. n Logical design – all functional features of the system chosen for development in analysis are described independently of any computer platform. Chapter 1 16
- 17. Systems Development Life Cycle (SDLC) (Cont.) n Physical design – the logical specifications of the system from logical design are transformed into the technologyspecific details from which all programming and system construction can be accomplished. Chapter 1 17
- 18. Systems Development Life Cycle (SDLC) (Cont.) n Implementation – the information system is coded, tested, installed and supported in the organization. n Maintenance – an information system is systematically repaired and improved. Chapter 1 18
- 19. Chapter 1 19
- 20. The Heart of the Systems Development Process Current practice combines analysis, design, and implementation into a single iterative and parallel process of activities Chapter 1 20
- 21. Traditional Waterfall SDLC One phase begins when another completes, little backtracking and looping Chapter 1 21
- 22. Problems with Waterfall Approach n System requirements “locked in” after being determined (can't change). n Limited user involvement (only in requirements phase). n Too much focus on milestone deadlines of SDLC phases to the detriment of sound development practices. Chapter 1 22
- 25. Prototyping n Iterative development process: n Requirements quickly converted to a working system. n System is continually revised. n Close collaboration between users and analysts. Chapter 1 25
- 27. ComputerAided Software Engineering (CASE) Tools n Diagramming tools enable graphical representation. n Computer displays and report generators help prototype how systems “look and feel”. Chapter 1 27
- 28. ComputerAided Software Engineering (CASE) Tools (Cont.) n Analysis tools automatically check for consistency in diagrams, forms, and reports. n Central repository for integrated storage of diagrams, reports, and project management specifications. Chapter 1 28
- 29. ComputerAided Software Engineering (CASE) Tools (Cont.) n Documentation generators standardize technical and user documentation. n Code generators enable automatic generation of programs and database code directly from design documents, diagrams, forms, and reports. Chapter 1 29
- 30. CASE Tools (Cont.) Figure 112 A class diagram from IBM’s Rational Rose Chapter 1 30
- 31. CASE Tools (Cont.) Chapter 1 31
- 32. Joint Application Design (JAD) n Structured process involving users, analysts, and managers. n Severalday intensive workgroup sessions. n Purpose: to specify or review system requirements. Chapter 1 32
- 33. Rapid Application Development (RAD) n Methodology to radically decrease design and implementation time. n Involves: extensive user involvement, prototyping, JAD sessions, integrated CASE tools, and code generators. Chapter 1 33
- 35. Agile Methodologies n Motivated by recognition of software development as fluid, unpredictable, and dynamic. n Three key principles ¨ Adaptive rather than predictive. ¨ Emphasize people rather than roles. ¨ Selfadaptive processes. Chapter 1 35
- 37. eXtreme Programming n Short, incremental development cycles. n Automated tests. n Twoperson programming teams. Chapter 1 37
- 38. eXtreme Programming (Cont.) n Coding and testing operate together. n Advantages: ¨ Communication between developers. ¨ High level of productivity. ¨ Highquality code. Chapter 1 38
- 39. ObjectOriented Analysis and Design (OOAD) n Based on objects rather than data or processes. n Object: a structure encapsulating attributes and behaviors of a real world entity. Chapter 1 39
- 40. ObjectOriented Analysis and Design (OOAD) (Cont.) n Object class: a logical grouping of objects sharing the same attributes and behaviors. n Inheritance: hierarchical arrangement of classes enable subclasses to inherit properties of superclasses. Chapter 1 40
- 41. Rational Unified Process (RUP) n An objectoriented systems development methodology. n RUP establishes four phase of development: inception, elaboration, construction, and transition. n Each phase is organized into a number of separate iterations. Chapter 1 41
- 42. Phases of OOSADbased Development Figure 114 Phases of OOSADbased development Chapter 1 42
- 43. Our Approach to Systems Development n The SDLC is an organizing and guiding principle in this book. n We may construct artificial boundaries or artificially separate activities and processes for learning purposes. n Our intent is to help you understand all the pieces and how to assemble them. Chapter 1 43
- 44. Summary n In this chapter you learned how to: ü Define information systems analysis and design. ü Describe the different types of information systems. ü Describe the information Systems Development Life Cycle (SDLC). Chapter 1 44
- 45. Summary (Cont.) ü Explain Rapid Application Development (RAD), prototyping, Joint Application Development (JAD), and Computer Aided Software Engineering (CASE). ü Describe agile methodologies and eXtreme programming. ü Explain Object Oriented Analysis and Design and the Rational Unified Process (RUP). Chapter 1 45