The Technical Design Document (TDD) and the Functional Design Document (FDD) serve different but complementary purposes in the software development lifecycle. Here’s a breakdown of their key differences:
Functional Design Document (FDD)
- Focus: Describes what the system should do from a functional perspective.
- Audience: Primarily business stakeholders, functional analysts, and end-users.
- Content:
- Business Requirements: Detailed descriptions of the business needs and objectives.
- Functional Specifications: Specific functionalities, use cases, and user interactions.
- System Inputs and Outputs: Data the system will receive and produce.
- Diagrams and Mockups: Visual representations like flowcharts and user interface mockups.
- Regulatory Compliance: How the system adheres to relevant regulations and standards.
Technical Design Document (TDD)
- Focus: Describes how the system will be built from a technical perspective.
- Audience: Primarily developers, architects, and technical stakeholders.
- Content:
- Introduction: Overview of the system, its purpose, and the problems it aims to solve.
- Design Goals and Constraints: Specific goals and constraints impacting the system’s architecture.
- Architectural Overview: High-level description of the system’s major components and their interactions.
- Functional Requirements: Detailed list of features and capabilities.
- Non-Functional Requirements: Performance, scalability, security, and reliability aspects.
- Data Design: Data model, database schema, and data migration or storage requirements.
Key Differences
- Purpose: FDD focuses on what the system should do (functional requirements), while TDD focuses on how the system will be built (technical requirements).
- Audience: FDD is aimed at business stakeholders and end-users, whereas TDD is aimed at technical teams.
- Content: FDD includes business requirements and functional specifications, while TDD includes architectural details, technical specifications, and data design.
Both documents are essential for ensuring that the system meets business needs and is technically sound.
Does this help clarify the differences between TDD and FDD?
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