Requirements gathering (functional and non-functional) in HLD - System Design Exercise

Design: Requirements Gathering Process

Focus on the process and best practices for gathering and documenting requirements. Out of scope are detailed design, implementation, and testing phases.

Functional Requirements

FR1: Identify and document functional requirements that describe what the system should do

FR2: Identify and document non-functional requirements that describe system qualities like performance, security, and usability

FR3: Ensure requirements are clear, measurable, and testable

FR4: Prioritize requirements based on stakeholder needs

FR5: Manage changes to requirements throughout the project lifecycle

Non-Functional Requirements

NFR1: Requirements must be gathered within a 2-week timeframe

NFR2: Stakeholder availability may be limited

NFR3: Requirements must be understandable by both technical and non-technical team members

NFR4: Maintain traceability between requirements and design decisions

Think Before You Design

Questions to Ask

❓ Question 1

❓ Question 2

❓ Question 3

❓ Question 4

❓ Question 5

Key Components

Stakeholder interviews and workshops

Requirement documentation templates

Prioritization frameworks (e.g., MoSCoW)

Traceability matrices

Change management process

Design Patterns

Use case modeling

User stories and acceptance criteria

Requirement decomposition

Non-functional requirement categorization

Version control for requirements

Reference Architecture

 +-------------------+       +---------------------+       +-------------------+
 | Stakeholder Input | ----> | Requirements Analyst | ----> | Requirements Doc  |
 +-------------------+       +---------------------+       +-------------------+
          |                            |                             |
          |                            |                             |
          v                            v                             v
 +-------------------+       +---------------------+       +-------------------+
 | Interviews &      |       | Prioritization &    |       | Traceability &    |
 | Workshops        |       | Validation          |       | Change Management |
 +-------------------+       +---------------------+       +-------------------+

Components

Stakeholder Input

Interviews, Surveys, Workshops

Gather initial needs and expectations from users and stakeholders

Requirements Analyst

Documentation tools (e.g., Word, Confluence)

Analyze, clarify, and document requirements

Requirements Documentation

Templates, Traceability Matrices

Store and organize functional and non-functional requirements

Prioritization Framework

MoSCoW method, spreadsheets

Rank requirements by importance and urgency

Change Management Process

Version control, approval workflows

Manage updates and revisions to requirements

Request Flow

1. Stakeholders provide input via interviews and workshops

2. Requirements analyst collects and clarifies needs

3. Functional and non-functional requirements are documented

4. Requirements are prioritized and validated with stakeholders

5. Traceability is established linking requirements to design and tests

6. Change requests are managed through a formal process

Database Schema

Entities: Requirement (id, type [functional/non-functional], description, priority, status), Stakeholder (id, name, role), RequirementChange (id, requirement_id, change_description, date, approved_by). Relationships: Stakeholder submits Requirement; Requirement has many RequirementChange records.

Scaling Discussion

Bottlenecks

Difficulty managing large numbers of requirements from many stakeholders

Ensuring consistent understanding across diverse teams

Tracking changes and maintaining traceability as requirements evolve

Solutions

Use specialized requirements management tools to handle volume and complexity

Standardize documentation formats and conduct regular review sessions

Implement automated traceability and version control systems

Interview Tips

Time: Spend 10 minutes understanding the importance of requirements, 15 minutes discussing functional vs non-functional requirements and gathering techniques, 10 minutes on documentation and change management, 10 minutes on scaling and challenges.

Clear distinction between functional and non-functional requirements

Importance of stakeholder communication and prioritization

Use of structured documentation and traceability

Handling changes and maintaining requirement quality

Challenges in scaling requirements management and practical solutions