Systems Analysis – ITEC 3155 Systems Analysis Tasks

1. Systems Analysis – ITEC 3155Systems Analysis Tasks

2. Learning Objectives • Explain the purpose and various phases of the systems development life cycle (SDLC) • Describe the two overall approaches used to develop information systems: the traditional method and the object-oriented method • Explain the differences between a model, a tool, a technique, and a methodology Systems Analysis and Design in a Changing World, 4th Edition

3. Learning Objectives (continued) • Describe some of the variations of the systems development life cycle (SDLC) • Describe the key features of current trends in systems development: the Unified Process (UP), Extreme Programming (XP), Agile Modeling, and Scrum • Explain how automated tools are used in system development Systems Analysis and Design in a Changing World, 4th Edition

4. The Systems Development Lifecycle (SDLC) • Systems development life cycle (SDLC) • The methodology that provides overall framework for managing systems development process. The phases a project or system goes through from its beginning to project or system completion. • In effect, the development process describes how the project is to be done. • The SDLC is a logical approach to building systems • The SDLC avoids the problem of rushing to create code • The SDLC allows thoughtful review of the project and whether to proceed further • All projects use some variation of SDLC Systems Analysis and Design in a Changing World, 4th Edition

5. SDLC and Problem Solving • Similar to problem-solving approach in lecture 1 • Organization recognizes problem (project planning) • Project team investigates, understands problem and solution requirements (analysis) • Solution is specified in detail (design) • System that solves problem is built and installed (implementation) • System used, maintained, and enhanced to continue to provide intended benefits (support) Systems Analysis and Design in a Changing World, 4th Edition

6. Five Phases of the Traditional SLDC(p.38) • Systems (Project) planning – initiate, ensure feasibility, plan schedule, obtain approval for project • Systems Analysis – understand business needs and processing requirements • Systems Design – define solution system based on requirements and analysis decisions • Systems Implementation – construct, test, train users, and install new system • Systems Support – keep system running Systems Analysis and Design in a Changing World, 4th Edition

7. Two Approaches to System Development(pp. 51-58) • Traditional approach • Also called structured system development • Structured analysis and design technique (SADT) • Includes information engineering (IE) • Object-oriented approach • Also called OOA, OOD, and OOP • Views information system as collection of interacting objects that work together to accomplish tasks Systems Analysis and Design in a Changing World, 4th Edition

8. Differences in the Traditional Structured vs. Object-Oriented approaches • Structured approaches take a top-down or decomposition approach, breaking models into further refined diagrams with more detail. Is therefore a sequential approach and assumes development from scratch. OO is more iterative and builds part of the system before the system is fully analyzed. • Both approaches focus on data and processes • Both approaches use models (abstractions) of the real world. • Both approaches use IDEs or CASE tools Systems Analysis and Design in a Changing World, 4th Edition

9. “Waterfall” Approach to the SDLC(p. 39) The old standard was known as the Waterfall method. This method was sequential, not conducive to changing requirements. (p.39) Systems Analysis and Design in a Changing World, 4th Edition

10. Data Flow Diagram (DFD) Created Using Structured Analysis Technique (Figure 2-15) • Dataflow diagrams (DFDs) – shows processes with database interactions or data being passed between processes. (p.54) Systems Analysis and Design in a Changing World, 4th Edition

11. Entity-Relationship Diagram (ERD) Created Using Structured Analysis Technique • “Information engineering” approach if data is emphasized over processes / functions. Also IE begins by looking at the strategic plan of the organization and decomposing it into data (p. 55) • Show data at rest (or static data). Static means a snapshot. Systems Analysis and Design in a Changing World, 4th Edition

12. Criticism of structured approaches • In structured approaches, the emphasis is on the analysis phase and models that are static. They do not show the interactions of components (such as the logic or programming code). The result is that often there is a gap between drawing DFDs and ERDs and the actual detailed design and implementation phases. Systems Analysis and Design in a Changing World, 4th Edition

13. Newer Approaches to the SDLC • Spiral Model (Fig 2-6) • Project cycles through development activities over and over until project is complete • Prototype created by end of each cycle • Focuses on mitigating risk • Uses Iteration Systems Analysis and Design in a Changing World, 4th Edition

14. Iteration (p. 56) • Iteration – Work activities are repeated • Each iteration refines previous result • Approach assumes no one gets it right the first time • There are a series of mini projects for each iteration Systems Analysis and Design in a Changing World, 4th Edition

15. Methodologies and Models(pp. 47-48) • Methodologies • Comprehensive guidelines to follow for completing every SDLC activity • Collection of models, tools, and techniques • Models • Representation of an important aspect of real world, but not same as real thing • Abstraction used to separate out aspect • Diagrams and charts • Project planning and budgeting aids Systems Analysis and Design in a Changing World, 4th Edition

16. Tools and Techniques(pp. 48-49) • Tools • Software support that helps create models or other required project components • Range from simple drawing programs to complex CASE tools to project management software • Techniques • Collection of guidelines that help analysts complete a system development activity or task • Can be step-by-step instructions or just general advice Systems Analysis and Design in a Changing World, 4th Edition

17. Object-Oriented Approach • Completely different approach to information systems • Views information system as collection of interacting objects that work together to accomplish tasks • Objects– things in computer system that can respond to messages • Conceptually, no processes, programs, data entities, or files are defined – just objects • OO languages: Java, C++, C# .NET, VB .NET Systems Analysis and Design in a Changing World, 4th Edition

18. Object-Oriented Approach (continued) • Object-oriented analysis (OOA) • Defines types of objects users deal with • Shows use cases are required to complete tasks • Object-oriented design (OOD) • Defines object types needed to communicate with people and devices in system • Shows how objects interact to complete tasks • Refines each type of object for implementation with specific language of environment • Object-oriented programming (OOP) • Writing statements in programming language to define what each type of object does Systems Analysis and Design in a Changing World, 4th Edition

19. Class Diagram Created During OO Analysis Systems Analysis and Design in a Changing World, 4th Edition

20. SDLC Variations • Many variations of SDLC in practice • Based on variation of names for phases • No matter which one, activities/tasks are similar • Some increase emphasis on people • User-centered design, participatory design • Some increase speed of development • Rapid application development (RAD) • Prototyping Systems Analysis and Design in a Changing World, 4th Edition

21. Current Trends in Development • The Unified Process (UP) • Extreme Programming (XP) • Agile Modeling • Scrum Systems Analysis and Design in a Changing World, 4th Edition

22. The Unified Process (UP)(pp. 61-62) • Object-oriented development approach • Offered by IBM / Rational • Booch, Rumbaugh, Jacobson • Unified Modeling Language (UML) used primarily for modeling • UP defines four life cycle phases • Inception, elaboration, construction, transition Systems Analysis and Design in a Changing World, 4th Edition

23. The SDLC Phases of the UP • Four life cycle “phases”: • Inception - scope, participants, business purpose and initial budget and schedule estimates. Scope is defined through a context diagram and use cases. Unified Modeling Language (UML) used primarily for modeling • Elaboration – defines requirements, designs the solution, implement the solution using use case diagrams, class diagrams, sequence diagrams. Costs and benefit estimates occur at the end of this phase. • Construction – additional requirements, design and implementation • Transition – turn system over to the users • Note that Inception and Elaboration are similar to Systems Planning and Analysis in the traditional SDLC Systems Analysis and Design in a Changing World, 4th Edition

24. The Unified Process (UP) (continued) • Reinforces six best practices of systems development • Develop iteratively • Define and manage system requirements • Use component architectures • Create visual models • Verify quality • Control changes Systems Analysis and Design in a Changing World, 4th Edition

25. Extreme Programming (XP)(p.62) • Recent, lightweight, development approach to keep process simple and efficient • Describes system support needed and required system functionality through informal user stories • Has users describe acceptance tests to demonstrate defined outcomes • Relies on continuous testing and integration, heavy user involvement, programming done by small teams Systems Analysis and Design in a Changing World, 4th Edition

26. Agile Modeling(pp. 62-63) • Hybrid of XP and UP; has more models than XP, fewer documents than UP • Interactive and Incremental Modeling • Apply right models • Create several models in parallel • Model in small increments • Teamwork • Get active stakeholder participation • Encourage collective ownership • Model with others and display models publicly Systems Analysis and Design in a Changing World, 4th Edition

27. Agile Modeling (continued) • Simplicity • Use simple content • Depict models simply • Use simplest modeling tools • Validation • Consider testability • Prove model is right with code Systems Analysis and Design in a Changing World, 4th Edition

28. Scrum(p.63) • For highly adaptive project needs • Respond to situation as rapidly as possible • Scrum refers to rugby game • Both are quick, agile, and self-organizing • Team retains control over project • Values individuals over processes Systems Analysis and Design in a Changing World, 4th Edition

29. Tools to Support System Development(pp.63-67) • Computer-aided system engineering (CASE) • Automated tools to improve the speed and quality of system development work • CASE systems offer tools to automate, manage and simplify the development process. CASE is available for traditional structured approaches as well as object-oriented approaches. • Summarizing initial requirements • Developing flow diagrams • Scheduling development tasks • Preparing documentation • Controlling software versions (configuration management) • Developing or generating program code (forward engineering) • Generating models from existing code (reverse engineering) Systems Analysis and Design in a Changing World, 4th Edition

30. CASE Tool Repository Contains All System Information Systems Analysis and Design in a Changing World, 4th Edition

31. Summary • System development projects are organized around the systems development life cycle (SDLC) • Some projects use a predictive approach to the SDLC, and others use a more adaptive approach to the SDLC • SDLC phases include project planning, analysis, design, implementation, and support Systems Analysis and Design in a Changing World, 4th Edition

32. Summary (continued) • In practice, phases overlap, and projects contain many iterations of analysis, design, and implementation • Models, techniques, and tools make up a system development methodology • System development methodology provides guidelines to complete every activity in the SDLC Systems Analysis and Design in a Changing World, 4th Edition

33. Summary (continued) • System development methodologies are based on traditional approach or object-oriented approach • Current trends include: Extreme Programming (XP), Unified Process (UP), Agile Modeling, and Scrum • CASE tools are designed to help analysts complete system development tasks Systems Analysis and Design in a Changing World, 4th Edition

34. Next Class • Read Chapter 4 • Read “Make requirements gathering interviews less stressful for users” • Assignments for Term Project Systems Analysis and Design in a Changing World, 4th Edition