What is referential integrity in SQL?

What is referential integrity in SQL?

Referential integrity is a database concept that ensures relationships between tables remain consistent. It means that a foreign key in one table must match a primary key in another table, or be null.

Can you give me an example of how it works?

Sure! If you have a 'Customers' table with a 'CustomerID' as the primary key, and an 'Orders' table with a 'CustomerID' as a foreign key, every order must be linked to a valid customer.

What happens if I try to delete a customer who has orders?

If you try to delete that customer without handling the orders, it will violate referential integrity. Most databases will prevent the deletion unless you first delete or update the related orders.

How can I enforce referential integrity in my database?

You can enforce referential integrity by defining foreign key constraints when creating or altering your tables.