Choose DynamoDB vs MySQL for a backend
Company: Salesforce
Role: Software Engineer
Category: Software Engineering Fundamentals
Difficulty: medium
Interview Round: Technical Screen
In a backend system, you must choose a primary database for a core service. Explain **when you would choose a key-value/NoSQL store (e.g., DynamoDB-like)** versus a **relational database (e.g., MySQL-like)**.
Address:
- Data model and access patterns
- Query needs (ad-hoc queries, joins, aggregates)
- Consistency, transactions, and constraints
- Scalability, operational overhead, and cost
- Typical examples where each is the better choice
Quick Answer: This question evaluates a candidate's ability to reason about data modeling, access patterns, query complexity, consistency and transactional requirements, scalability, operational overhead, and cost when choosing between a key-value/NoSQL store and a relational database.