Requirements analysis in LLD - Cheat Sheet & Quick Revision

Recall & Review

beginner

What is Requirements Analysis in system design?

Requirements Analysis is the process of understanding and documenting what a system must do. It helps to gather clear and complete needs from users and stakeholders before building the system.

beginner

Why is Requirements Analysis important before system development?

It prevents misunderstandings, reduces costly changes later, and ensures the system meets user needs by clearly defining what to build.

beginner

Name two main types of requirements in Requirements Analysis.

Functional requirements describe what the system should do. Non-functional requirements describe how the system performs tasks, like speed or security.

intermediate

What is a use case in Requirements Analysis?

A use case is a simple story that shows how a user interacts with the system to achieve a goal. It helps to understand system behavior from the user's view.

intermediate

How does Requirements Analysis connect to system design?

It provides a clear list of what the system must do, guiding architects and developers to create a system that fits user needs and constraints.

What is the main goal of Requirements Analysis?

A To deploy the system to users

B To write code for the system

C To test the system after development

D To understand and document what the system must do

Requirements Analysis focuses on gathering and understanding system needs before building it.

Which of these is a functional requirement?

A The system must send email notifications

B The system must respond within 2 seconds

C The system must be secure

D The system must have a blue theme

Functional requirements describe what the system does, like sending emails.

What does a use case describe?

A The programming language used

B The system's database schema

C How a user interacts with the system to achieve a goal

D The system's hardware requirements

Use cases show user interactions and goals with the system.

Which is NOT a benefit of good Requirements Analysis?

A Reduced development cost

B Faster coding without planning

C Clear understanding of system needs

D Fewer changes after development

Skipping planning leads to problems; good analysis helps avoid this.

Non-functional requirements include:

A System speed and security

B User login feature

C Data input forms

D Report generation

Non-functional requirements describe qualities like speed and security.

Explain the purpose and key steps of Requirements Analysis in system design.

Think about how you would gather and write down what a new app should do.

Describe the difference between functional and non-functional requirements with examples.

Functional is what the system does; non-functional is how well it does it.

Practice

1. What is the main purpose of requirements analysis in system design?

easy

A. To deploy the system to users

B. To write the system code

C. To test the system performance

D. To define what the system must do

Solution

1. Step 1: Understand the role of requirements analysis

   Requirements analysis focuses on understanding and defining the system's needs and functions.

2. Step 2: Differentiate from other phases

   Writing code, testing, and deployment happen after requirements are clear.

3. Final Answer:

   To define what the system must do -> Option D

4. Quick Check:

   Requirements analysis = Define system needs [OK]

Hint: Requirements analysis = What system must do [OK]

Common Mistakes:

• Confusing requirements analysis with coding
• Thinking testing is part of requirements
• Mixing deployment with requirements gathering

2. Which of the following is a correct step in requirements analysis?

easy

A. Writing deployment scripts

B. Compiling source code

C. Gathering user needs

D. Running system tests

Solution

1. Step 1: Identify key activities in requirements analysis

   Gathering user needs is essential to understand what the system should do.

2. Step 2: Exclude unrelated activities

   Deployment scripts, compiling code, and testing happen after requirements are set.

3. Final Answer:

   Gathering user needs -> Option C

4. Quick Check:

   Requirements analysis = Gather needs [OK]

Hint: Gather user needs first in requirements analysis [OK]

Common Mistakes:

• Mixing coding or deployment with requirements
• Ignoring user input during analysis
• Confusing testing with requirements gathering

3. Given these requirements:
- System must handle 1000 users simultaneously
- Data must be encrypted
- Users can reset passwords
Which requirement type is "Data must be encrypted"?

medium

A. Non-functional requirement

B. Functional requirement

C. Business requirement

D. User interface requirement

Solution

1. Step 1: Classify the requirement "Data must be encrypted"

   This describes a quality or constraint on the system, not a specific function.

2. Step 2: Understand requirement types

   Functional requirements describe actions; non-functional describe qualities like security.

3. Final Answer:

   Non-functional requirement -> Option A

4. Quick Check:

   Encryption = Non-functional requirement [OK]

Hint: Security needs are non-functional requirements [OK]

Common Mistakes:

• Confusing security with functional features
• Mixing business goals with technical details
• Assuming all requirements are functional

4. A requirements document states: "Users must login with username and password." Later, it says: "Users can login using email and password." What is the main issue here?

medium

A. Performance bottleneck

B. Ambiguous requirements

C. Security vulnerability

D. Scalability problem

Solution

1. Step 1: Identify conflicting statements

   The document gives two different login methods without clarifying which is correct.

2. Step 2: Understand impact of ambiguity

   Ambiguous requirements confuse developers and cause design errors.

3. Final Answer:

   Ambiguous requirements -> Option B

4. Quick Check:

   Conflicting login info = Ambiguity [OK]

Hint: Conflicting info means ambiguous requirements [OK]

Common Mistakes:

• Assuming security or performance issues without evidence
• Ignoring requirement conflicts
• Thinking scalability relates to login methods

5. You are designing a messaging app. Which of these is the best way to gather requirements to ensure scalability and user satisfaction?

hard

A. Interview users, analyze competitors, and document clear functional and non-functional needs

B. Start coding immediately based on your assumptions

C. Only focus on UI design without backend planning

D. Ignore user feedback and add features later

Solution

1. Step 1: Identify best practices in requirements gathering

   Interviewing users and analyzing competitors helps understand real needs and market standards.

2. Step 2: Emphasize clear documentation of all requirements

   Clear functional and non-functional requirements guide scalable and user-friendly design.

3. Final Answer:

   Interview users, analyze competitors, and document clear functional and non-functional needs -> Option A

4. Quick Check:

   User research + clear docs = good requirements [OK]

Hint: Gather user input and document clearly before coding [OK]

Common Mistakes:

• Skipping user research
• Starting development without clear requirements
• Ignoring backend needs for scalability