What are indexes and why are they important?

Short answer: Indexes are data structures that speed up the retrieval of data from a database. They work like the index in a book, allowing quick lookup of data without having to scan the entire table. Importance: Faster Searches: Improves query performance, especially for large datasets. Efficient Sorting: Helps in sorting and filtering operations. Primary and Foreign Keys: Automatically indexed to ensure quick data retrieval.

Real-world example (ShopNest)

ShopNest adds an index on Orders(CustomerId, CreatedAt) because “my recent orders” is queried constantly.

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.