What is a transaction in SQL?

Short answer: Can you explain the transaction lifecycle? A transaction in SQL is a sequence of operations performed as a single unit of work. Transactions ensure that database operations are performed atomically. Lifecycle:

Real-world example (ShopNest)

Checkout wraps stock decrement + order insert in a transaction so you never sell stock you do not have.

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.