What are collections and databases in MongoDB?

Short answer: Database: A container for collections. MongoDB allows you to have multiple databases within the same instance. Collection: A group of MongoDB documents. Collections are similar to tables in SQL but don’t have a fixed schema.

Real-world example (ShopNest)

ShopNest’s SQL Server database stores customers, products, and orders. Good indexes and clear foreign keys keep checkout queries fast and safe.

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.