What is isolation level in SQL?

Short answer: Can you explain the different isolation levels (e.g., READ UNCOMMITTED, READ COMMITTED, REPEATABLE READ, SERIALIZABLE)?

Explain a bit more

The isolation level in SQL defines how transactions interact with each other in terms of visibility of data. The isolation level affects the balance between data consistency and transaction concurrency. READ UNCOMMITTED: Allows dirty reads. One transaction can see uncommitted changes made by another transaction. This is the lowest level of isolation. READ COMMITTED: Prevents dirty reads, but allows non-repeatable reads (data can change during the transaction). REPEATABLE READ: Prevents dirty reads and non-repeatable reads, but phantom reads (new rows can appear in a query) are still possible. SERIALIZABLE: The highest isolation level. Prevents dirty reads, non-repeatable reads, and phantom reads by making transactions execute sequentially.

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.