What are the different types of design documents used in the SDLC?

In the Software Development Life Cycle (SDLC), there are several types of design documents used to document the design phase of the software development process. These design documents help in defining the architecture, structure, and functionality of the software system being developed. The different types of design documents used in the SDLC include:

1. System Design Document (SDD): This document provides an overview of the entire system being developed. It includes information about the system architecture, hardware and software requirements, data flow diagrams, and interfaces with other systems. The SDD serves as a blueprint for the development team to understand the overall design of the system.

2. High-Level Design Document (HLDD): The HLDD focuses on the overall structure and modules of the software system. It describes the system's components, their interactions, and the data flow between them. The HLDD provides a detailed view of the system's functionality and helps in identifying the major modules and their relationships.

3. Low-Level Design Document (LLDD): The LLDD provides a detailed design of each module identified in the HLDD. It includes information about the module's internal structure, algorithms, data structures, and interfaces. The LLDD serves as a guide for the developers to implement the modules and ensures consistency in the design across the development team.

4. Database Design Document: This document focuses on the design of the database schema and its relationships. It includes entity-relationship diagrams, data models, table structures, and constraints. The database design document helps in ensuring efficient data storage and retrieval within the software system.

5. User Interface (UI) Design Document: The UI design document describes the visual layout and interaction flow of the software system's user interface. It includes wireframes, mockups, and design guidelines for the user interface elements. The UI design document helps in creating a user-friendly and intuitive interface for the end-users.

6. Test Design Document: The test design document outlines the test strategy, test scenarios, and test cases to be executed during the testing phase of the SDLC. It includes information about the test environment, test data, and expected results. The test design document ensures comprehensive testing of the software system to identify and fix any defects or issues.

These design documents play a crucial role in the SDLC as they provide a clear understanding of the software system's design and facilitate effective communication among the development team members. They serve as a reference for the developers, testers, and other stakeholders involved in the software development process.