Slide 1 Systems Analysis and Design With UML 2.0 An Object-Oriented Approach, Second Edition Chapter 1: Introduction to Systems Analysis and Design Alan Dennis, Barbara Wixom, and David Tegarden © 2005 John Wiley & Sons, Inc.

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Slide 3 INTRODUCTION Chapter 1

Slide 4 Key Ideas Many failed systems were abandoned because analysts tried to build wonderful systems without understanding the organization. The primarily goal is to create value for the organization.

Slide 5 Key Ideas The systems analyst is a key person analyzing the business, identifying opportunities for improvement, and designing information systems to implement these ideas. It is important to understand and develop through practice the skills needed to successfully design and implement new information systems.

Slide 6 THE SYSTEMS DEVELOPMENT LIFE CYCLE

Slide 7 Major Attributes of the Lifecycle The project Moves systematically through phases where each phase has a standard set of outputs Produces project deliverables Uses deliverables in implementation Results in actual information system Uses gradual refinement

Slide 8 Major Attributes of the Lifecycle The SDLC The SDLC has a set of four fundamental phases:  Planning  Analysis  Design  Implementation

Slide 9 Project Phases Planning Why build the system? Analysis Who, what, when, where will the system be? Design How will the system work? Implementation System delivery

Slide 10 Project Phases Planning Often called project initiation Concept of the product is explored and refined Client’s general requirements are elicited Added by Dr. Stoecklin

Slide 11 Project Phases Planning Tasks Identifying business value Analyze feasibility Analyze risks Develop work plan Staff the project Control and direct project Added by Dr. Stoecklin

Slide 12 Project Phases Analysis Who uses the system, what specifications are produced Client’s requirements are analyzed and presented in Software Requirements Specification (SRS) document Software Project Management Plan Added by Dr. Stoecklin

Slide 13 Project Phases Analysis Tasks Analysis Information gathering Process modeling Data modeling Added by Dr. Stoecklin

Slide 14 Project Phases Design Describes “HOW the product does it” Architectural design (high-level design)  Product as a whole is broken down into components, called modules Detailed design (low-level design)  Each module is designed Output: Design document Added by Dr. Stoecklin

Slide 15 Project Phases Design Tasks Physical design Architectural design Interface design Database and file design Program design Added by Dr. Stoecklin

Slide 16 Project Phases Implementation Coding and testing of individual software components Combination and testing of software components Acceptance testing by client Ends with the product being accepted by the client and installed on the client’s computer Added by Dr. Stoecklin

Slide 17 Project Phases Implementation Tasks Construction Installation Added by Dr. Stoecklin

Slide 18 Processes and Deliverables ProcessProduct Planning Analysis Design Implementation Project Plan System Requirements Specifications System Design Specification New System and Maintenance Plan Modified by Dr. Stoecklin

Slide 19 SYSTEM DEVELOPMENT Methodologies

Slide 20 What Is a Methodology? A formalized approach or series of steps Writing code without a well- thought-out system request may work for small programs, but rarely works for large ones.

Slide 21 Structured Design Projects move methodically from one to the next step Generally, a step is finished before the next one begins

Slide 22 Waterfall Development Method First documented process model for software development. Modified by Dr. Stoecklin

Slide 23 Pros and Cons of the Waterfall Method ProsCons Identifies requirements long before programming Begins Enforces a disciplined approach Implies testing inherent to each phase. Forces delivery of documents needed in the development process. Easy to explain to customers. Design must be specified on paper before programming begins Long time between system proposal and delivery of new system. Real projects rarely follow sequential flow. Requirements difficult to completely document up front. Modified by Dr. Stoecklin

Slide 24 Code and Fix Model Included by Dr. Stoecklin

Slide 25 RAD Development Included by Dr. Stoecklin

Slide 26 Pros and Cons of the RAD Method Pros Cons delivers to customer what customer really needs customer thinks product is almost done Modified by Dr. Stoecklin Rapid prototype working model functionally equivalent to a subset of the product Concentrates on experimenting with those parts of the customer’s requirements that are poorly understood Included by Dr. Stoecklin

Slide 27 Spiral Development Included by Dr. Stoecklin

Slide 28 Spiral Development Included by Dr. Stoecklin

Slide 29 Pros and Cons of the Spiral Method Pros Cons emphasizes looking at alternatives and constraints during risk analysis intended exclusively for internal development of large- scale software risk analysis is time- consuming Included by Dr. Stoecklin Goal: minimizing risk of software development each phase includes risk management to minimize and control risk

Slide 30 Incremental Development Incremental Model 1)operational system one currently being used by the customer and users 2)development system next version that is being prepared to replace current operational system Refer to systems using release numbers: users use Release 1 while developers are building Release 2 Included by Dr. Stoecklin

Slide 31 Pros and Cons of the Incremental Method Pros Cons customers do not have to wait until the entire system is delivered to benefit from it lower risk of overall project failure training can begin on early versions frequent releases allow developers to fix problems found in previous release can grab market share early customers and users do beta testing too many versions may degenerate into build-and-fix Included by Dr. Stoecklin

Slide 32 Parallel Development

Slide 33 Alternatives to the SDLC Agile Development Phased Development Prototyping Throw-Away Prototyping Unified Process

Slide 34 Rapid Application Development (generic term) Critical elements CASE tools JAD sessions Fourth generation/visualization programming languages Code generators

Slide 35 Rapid Application Development Categories Phased development A series of versions Prototyping System prototyping Throw-away prototyping Design prototyping Agile Development Extreme Development

Slide 36 Agile Development A collection of new paradigms characterized by Less emphasis on analysis and design Earlier implementation (working software is considered more important than documentation) Responsiveness to change Close collaboration with the client Included by Dr. Stoecklin

Slide 37 Extreme Programming Stories (features client wants) Estimate duration and cost of each story Select stories for next build Each build is divided into tasks Test cases for a task are drawn up first Pair programming Included by Dr. Stoecklin

Slide 38 Microsoft Development Microsoft’s life-cycle model Steps: Requirements analysis — interview potential customers Draw up specifications Divide project into 3 or 4 builds Each build is carried out by small teams working in parallel Included by Dr. Stoecklin

Slide 39 How Prototyping Works

Slide 40 Throwaway Prototyping

Slide 41 Selecting the Appropriate Methodology Clarity of User Requirements Familiarity with Technology System Complexity System Reliability Short Time Schedules Schedule Visibility

Slide 42 Criteria for Selecting a Methodology

Slide 43 Unified Process The leading object-oriented methodology for the development of large-scale software Basic Characteristics of the Unified Process Object-oriented Use-case driven Architecture centric Iteration and incrementation Included by Dr. Stoecklin

Slide 44 Project Team Roles and Skills

Slide 45 Information Systems Roles Business analyst System analyst Infrastructure analyst Change management analyst Project manager

Slide 46 Project Team Roles

Slide 47 Summary -- Part 1 The Systems Development Lifecycle consists of four stages: Planning, Analysis, Design, and Implementation The major development methodologies: Structured design  the waterfall method  Parallel development RAD development  Prototyping (regular and throwaway) Agile development  XP streamline SDLC

Slide 48 Summary -- Part 2 There are five major team roles: business analyst, systems analyst, infrastructure analyst, change management analyst and project manager.