Denormalization:?

Short answer: A pattern used to improve performance by storing redundant data, reducing the need for complex joins, and speeding up read queries. Used in data warehousing and systems requiring fast reads.

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.