What is CAP theorem in distributed databases?

Short answer: The CAP theorem (Consistency, Availability, Partition Tolerance) states that in a distributed database system, it is impossible to simultaneously guarantee all three of the following:

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.