What is database caching and how does it improve performance?

Short answer: Database caching involves storing frequently accessed data in a faster storage layer (e.g., memory) so that future requests for the same data can be served more quickly, reducing the need to query the database repeatedly.

Explain a bit more

How it improves performance: Reduces database load: Instead of querying the database every time data is requested, the cache can provide instant access to commonly requested data. Improves response time: Caching data in-memory (using technologies like Redis or Memcached) makes it accessible in nanoseconds, compared to the millisecond access time of traditional disk-based databases. Reduces latency: Caching significantly reduces the time taken to fetch data, improving the overall user experience. Example: Frequently accessed user profiles in a web application can be cached using Redis, so that subsequent requests don't have to query the database again.

Say this in the interview

1. Define — one clear sentence (the short answer above).
2. Example — relate it to a project like ShopNest or your real work.
3. Trade-off — when you would not use it.