System Development Life Cycle(SDLC)

 

System Development Life Cycle (SDLC) 

Introduction

The System Development Life Cycle (SDLC) is a systematic process used to develop information systems or software solutions. It provides a structured approach to planning, creating, testing, deploying, and maintaining information systems. Each phase has specific goals and deliverables, ensuring that projects meet business needs and are delivered efficiently.

                                                                    Fig.1 SDLC

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Steps Of SDLC :

1. Planning Phase

The first phase in the SDLC is the planning phase. It serves as the foundation for the entire project. During this phase, the problem or opportunity is identified, and business needs are analyzed. Organizations evaluate whether a new system is needed or whether an existing system requires improvements.

Several feasibility studies are conducted:

• Technical feasibility (Can the system be built with current technology?)

• Economic feasibility (Is it cost-effective?)

• Operational feasibility (Will it function properly in the organization?)

• Legal feasibility (Are there legal constraints?)

Project goals are defined, resources are allocated, timelines are created, and a high-level project plan is developed. Risks are assessed and mitigation plans are prepared. The outcome of this phase is usually a Project Charter or a Feasibility Study Report which serves as a green light for moving forward.

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2. System Analysis Phase

Once the project is approved, the system analysis phase begins. Here, detailed information is gathered to understand the system's exact needs.

Analysts work closely with stakeholders, end-users, and business experts to collect and document:

• Functional requirements (what the system should do)

• Non-functional requirements (performance, security, usability, etc.)

• Business processes currently in place

Tools such as interviews, questionnaires, observation, and document analysis are used. Analysts may also create models like:

• Use Case Diagrams

• Data Flow Diagrams (DFDs)

• Entity-Relationship Diagrams (ERDs)

The result is a Software Requirements Specification (SRS) document that becomes the blueprint for the design phase.

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3. Design Phase

With clear requirements in hand, the design phase focuses on defining how the system will work.

There are two levels of design:

• High-Level Design (HLD): Defines overall architecture, system components, modules, and data flow.

• Low-Level Design (LLD): Provides detailed descriptions of each module, interface, database schema, and algorithms.

This phase includes:

• Choosing hardware and software platforms

• Designing user interfaces (UI)

• Planning system integration

• Defining network requirements

• Addressing security, scalability, and performance needs

Design documents are reviewed and approved by stakeholders before moving forward.

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4. Development (Implementation) Phase

The development phase is where the actual system is built. Developers write code following the specifications laid out in the design documents. This phase involves:

• Setting up development environments

• Writing and testing code (unit testing)

• Building database structures

• Integrating system modules

The system begins to take shape as developers transform design documents into a working product. Source control tools are used to manage code versions and track changes.

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5. Testing Phase

Once the system is developed, it enters the testing phase. Here, the system is rigorously tested to ensure it works as intended and meets all requirements.

Different levels of testing are performed:

• Unit Testing: Tests individual components.

• Integration Testing: Ensures modules work together.

• System Testing: Validates the system as a whole.

• User Acceptance Testing (UAT): End-users verify the system meets their needs.

• Performance Testing: Checks system speed and responsiveness.

• Security Testing: Identifies vulnerabilities.

Any bugs or issues are reported, fixed, and re-tested. This cycle continues until the system is stable and reliable.

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6. Deployment Phase

After successful testing, the system is ready for deployment. This phase includes:

• Installing the system on production servers

• Migrating existing data (if necessary)

• Conducting final system checks

• Training users and IT staff

• Creating user manuals and support documentation

A "go-live" date is set, and the system becomes operational. In some cases, deployment may occur in stages to reduce risks.

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7. Maintenance and Support Phase

The final phase is maintenance and support. Even after deployment, systems need continuous attention. This phase involves:

• Monitoring system performance

• Fixing issues that arise (corrective maintenance)

• Making improvements or adding new features (adaptive and perfective maintenance)

• Updating security patches and software versions (preventive maintenance)

• Providing user support and help desk services

Regular maintenance ensures the system remains functional, efficient, and secure throughout its life.

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Summary of SDLC Phases

Phase	Description	Key Output
Planning	Identify objectives, assess feasibility	Project Charter
Analysis	Gather detailed requirements	SRS Document
Design	Create system architecture and design	Design Specifications
Development	Build the actual system	Source Code
Testing	Verify and validate system	Test Reports
Deployment	Launch the system	Live System
Maintenance	Ongoing support and updates	Maintenance Logs

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Conclusion

The SDLC ensures that systems are developed in a disciplined, organized, and efficient way. By following its stages, organizations can minimize risks, control costs, meet user expectations, and deliver reliable, high-quality software solutions.