What is the concept of referential integrity and how is it enforced in database design?

Short answer: Referential integrity ensures that relationships between tables are consistent.

Explain a bit more

Specifically, it ensures that a foreign key in one table must match a primary key or a unique key in another table. This prevents invalid references from being made. Enforcing Referencing Integrity: Use foreign keys to create relationships between tables. Enforce actions like ON DELETE CASCADE, ON UPDATE CASCADE, or ON DELETE RESTRICT to define how changes in parent tables affect related child tables. Example: A Foreign Key in the Orders table references the CustomerID in the Customers table. If you try to delete a customer that has associated orders, referential integrity will prevent the delete unless actions like CASCADE are specified.

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.