Module 2 System Development Life Cycle (SDLC)

Software Development Life Cycle (SDLC)

A systematic step-by-step process used by software developers to plan, design, develop, test, deploy, and maintain software applications within budget and schedule.

Primary Objectives of SDLC

Key Benefits of Using SDLC

Standardizes software development, improves teamwork and productivity, reduces project failure, controls costs, and makes testing more effective.

Phase 1: Planning Phase

The first stage of SDLC where project goals, scope, schedule, cost, feasibility, and stakeholders are identified.

Feasibility Study

An assessment conducted during the Planning Phase to determine whether a project is practical and worth pursuing.

The 4 Types of Feasibility

Phase 2: Requirements Analysis

The phase where developers closely communicate with stakeholders to identify, gather, and document what users need from the software.

Functional Requirements

Specifications describing what the system should do (e.g., Login, Registration, Payment, Search, Report Generation).

Non-Functional Requirements

Specifications describing how the system should perform (e.g., Security, Reliability, Speed, Scalability, Availability).

Phase 3: Design Phase

The phase that converts gathered requirements into a system blueprint (interfaces, databases, system architecture, security).

High-Level Design (HLD) vs. Low-Level Design (LLD)

Phase 4: Development Phase

The phase where developers write actual source code, build databases, develop APIs, and integrate modules.

Phase 5: Testing Phase

The process of verifying that the software works correctly, meets user requirements, and is free of bugs before deployment.

Phase 6: Deployment Phase

The process of releasing the software to users, including installation, server configuration, data migration, and user training.

Phase 7: Maintenance Phase

The ongoing phase to keep software operational, secure, and updated after deployment.

Flowchart

A diagram that illustrates the sequence of steps, activities, decisions, and workflow of a process using standardized symbols and arrows.

UML Diagrams (Unified Modeling Language)

Standardized visual diagrams used to document the structure and behavior of a system (e.g., Use Case, Class, Activity, Sequence, and State Diagrams).

ER Diagrams (Entity-Relationship Diagram)

A diagram that maps out data structures and shows the relationships between entities to help design databases.

Wireframe

A simple, low-detail visual layout of an interface focusing on structure, layout, and functionality without color or styling.

Mockup

A detailed, static visual representation showing the final appearance of an interface, including colors, fonts, images, and branding.

Unit Testing

Testing individual components or units of source code independently.

Integration Testing

Testing the interaction and data flow between integrated modules.

System Testing

Testing the entire, complete software application end-to-end.

Acceptance Testing

Final testing conducted by users/clients to verify business requirements before deployment.

Direct Deployment

The old system is immediately shut down and replaced by the new system.

Parallel Deployment

Both the old system and the new system run side-by-side until the new system is verified.

Pilot Deployment

The new system is released to a small, limited group of users to test in a live environment first.

Phased Deployment

The new system is rolled out gradually in stages or modules.

Corrective Maintenance

Fixing reported bugs, errors, and defects in the software.

Adaptive Maintenance

Modifying the software to adapt to new environments (e.g., new operating systems, hardware, or cloud platforms).

Perfective Maintenance

Enhancing software performance and adding new features requested by users.

Preventive Maintenance

Making proactive modifications to prevent future software failures and reduce risks.

Requirements Gathering Activities

Conducting interviews, observing users, distributing questionnaires, holding workshops, and gathering business requirements.

Development Phase Activities

Writing source code, creating databases, developing APIs, and integrating modules.

Deployment Phase Activities

Installing software, configuring servers, migrating data, training users, and monitoring the live system.

Class Diagram (UML)

A structural UML diagram that visualizes the classes, attributes, methods, and relationships within an object-oriented system.

Sequence Diagram (UML)

A behavioral UML diagram that documents the chronological sequence of interactions and messages passed between objects over time.

Activity Diagram (UML)

A behavioral diagram that illustrates the step-by-step workflow of operational components and decision logic within a system.

State Diagram (UML)

A diagram that shows the different states an object transitions through in response to external events.