What are the different normal forms (1NF, 2NF, 3NF, BCNF, 4NF, etc.)?

Short answer: Normal forms are guidelines used to organize a relational database schema.

Explain a bit more

Each form addresses a different kind of redundancy or dependency.

Real-world example (ShopNest)

Product and Category are separate tables (normalized). The order line stores product id + price snapshot—not a giant duplicated product blob.

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.