Context

Interviewers ask this question to check whether you understand when a relational database is the right choice and when a non-relational system may be better. A strong answer should go beyond definitions and discuss tradeoffs.

Core Question

Explain the main differences between SQL and NoSQL databases. In your answer, cover:

1. How data is modeled and stored
2. Schema flexibility vs structured design
3. Typical consistency and transaction behavior
4. Common scaling patterns and performance tradeoffs
5. Example use cases where each approach is a better fit

Scope Guidance

Keep the answer practical and balanced. You do not need to list every NoSQL subtype in depth, but you should mention that NoSQL includes document, key-value, wide-column, and graph databases. The interviewer expects you to compare the systems clearly, note that neither is universally better, and explain how application requirements drive the choice.