Systems Analysis and Design PDF

Systems Analysis and Design 1. Comprehensive Definitions and Concepts 1.1 Systems Analysis Definition: Systems analysis involves a deep examination of existing processes, identifying inefficiencies, and detailing what a new or improved system should accomplish. It answers the...

Systems Analysis and Design 1. Comprehensive Definitions and Concepts 1.1 Systems Analysis Definition: Systems analysis involves a deep examination of existing processes, identifying inefficiencies, and detailing what a new or improved system should accomplish. It answers the question: What should the system do to meet user needs? Key Steps: o Information Gathering: Collecting data through interviews, observations, and document analysis. o Requirement Analysis: Defining functional and non-functional requirements. o Documentation: Creating detailed requirement specifications. Example: Analyzing the inventory management process in a retail chain to identify data flow bottlenecks and optimize stock control. 1.2 System Design Definition: This is the phase where detailed specifications are developed to determine how the system's components will interact to meet analysis requirements. It includes architectural design and interface design. Key Steps: o Logical Design: Outlining system functions without technology constraints. o Physical Design: Detailing how the system will be implemented using specific hardware and software. Example: Designing a relational database schema to handle customer orders and integrate with an online payment system. 1.3 System Development Life Cycle (SDLC) Definition: SDLC is a process framework for planning, creating, testing, and deploying an information system. Phases in Detail: 1. Planning: Determining project objectives, feasibility, and resource allocation. 2. Analysis: Gathering detailed user requirements and understanding existing systems. 3. Design: Developing models, system architecture, and interface layouts. 4. Implementation: Coding, integration, and rigorous system testing. 5. Support and Maintenance: Providing ongoing updates and troubleshooting. 2. In-Depth Visual Representations 2.1 Data Flow Diagrams (DFDs) Definition: DFDs depict how data flows through a system and its processing steps. They help identify where data enters and exits, and where it is stored. Detailed Symbols: o Process (Circle): Indicates an action or function. o Data Flow (Arrow): Shows data movement direction. o Data Store (Open Rectangle): Represents data storage locations. o External Entity (Rectangle): Signifies data sources or consumers. DFD Levels: o Context Diagram: The highest-level DFD showing the system as a single process. o Level 1 DFD: Breaks down the main process into sub-processes. Example DFD: [Customer] --> (Submit Order) --> [Order Processing System] (Submit Order) --> [Inventory Database] [Warehouse] [Product] 3. Types of Information Systems 3.1 Transaction Processing Systems (TPS) Definition: Systems that manage and record the day-to-day transactions of an organization. Detailed Example: A retail checkout system that captures sales, inventory updates, and customer purchases in real-time. 3.2 Management Information Systems (MIS) Definition: Provide reports based on TPS data to aid in planning and decision-making. Example: Weekly sales reports for store managers. 3.3 Decision Support Systems (DSS) Definition: Assist in decision-making by analyzing data and generating predictive insights. Detailed Example: Financial modeling software for budgeting and forecasting. 3.4 Enterprise Resource Planning (ERP) Definition: Integrated platforms that unify core business processes across departments. Example Systems: SAP, Oracle ERP. 4. Agile and Iterative Development Approaches 4.1 Agile Methodologies Definition: A flexible approach to development that emphasizes iterative progress, collaboration, and responsiveness to change. Core Practices: o Scrum Framework: Breaks work into sprints with defined tasks and roles. o Kanban Boards: Visualize workflow and manage tasks in real-time. Benefits: o Rapid delivery of functional software. o Enhanced adaptability to changing user needs. 4.2 Iterative Development Definition: Building a system incrementally, with each iteration refining features based on user feedback. Benefits Explained: o Early Issue Detection: Problems are identified early in the cycle. o Feedback Integration: Enhances product relevance by incorporating user suggestions. 5. Advanced Diagrams and Tools 5.1 System Sequence Diagrams (SSD) Definition: Visualize the sequence of operations between actors and the system. Elements: o Lifelines: Represent roles in the interaction. o Messages: Arrows showing the exchange of information. Example SSD: Customer -->|Request Item| Inventory System Inventory System -->|Confirm Availability| Customer. 5.2 UML Class Diagrams Definition: Represent the structure of classes in a system, including their attributes and methods. Class Components: o Name, Attributes, Operations: Sections of the class box. o Associations: Connect classes and show relationships. Sample Diagram: o Class: Order § Attributes: OrderID, Date § Methods: AddItem(), ProcessOrder() 5.3 Work Breakdown Structure (WBS) Definition: Hierarchical representation of project tasks, used for organizing and assigning responsibilities. Detailed Example: o Project Overview § Phase 1: Analysis § Gather Requirements § Create Initial DFDs § Phase 2: Design § Draft ERD § Develop Prototypes 6. Essential Project Management Practices 6.1 Detailed Work Breakdown Structure (WBS) Purpose: Provides clarity on task allocation and helps in scheduling and resource management. Techniques: o Decomposition: Breaking down large tasks into smaller, manageable ones. o Task Numbering: Assigning unique IDs for tracking. 6.2 Risk Management Strategies Definition: The systematic approach to identifying, analyzing, and responding to project risks. Examples: o Technical Risks: Lack of technical expertise, mitigated through training. o Schedule Risks: Delays in task completion, managed with buffer times. 6.3 Comprehensive Cost-Benefit Analysis Definition: Comparing the costs involved in a project to the anticipated benefits to justify proceeding. Example Metrics: o Net Present Value (NPV): Measures profitability. o Return on Investment (ROI): Assesses financial gains. 7. Project Challenges and Solutions 7.1 Common Reasons for Project Failure Incomplete Requirements: Results in unclear project direction. Solution: Engage stakeholders early and maintain continuous communication. 7.2 Best Practices for Success Clear Documentation: Ensure all requirements and project plans are detailed. Regular Stakeholder Involvement: Keep users informed to align project goals with expectations.