How do you implement multi-tenancy in databases?

Short answer: Multi-tenancy refers to a single instance of a database serving multiple tenants (clients or organizations) while keeping their data isolated. Approaches:

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.