Q.State whether the following statement is True or False and justify: 'A foreign key must always match a primary key value in the related table.'

This tests your understanding of how a foreign key enforces referential integrity between two tables.

True.

Justification: A foreign key is a field in one table whose values refer to the primary key of another table. For the link to be meaningful, each value entered in the foreign key must correspond to an existing primary-key value in the related table.

For example, if Orders.CustID is a foreign key referring to Customer.CustID, then every CustID recorded in Orders must be a customer that really exists in the Customer table. The database refuses an order for a non-existent customer. This rule is called referential integrity, and it is exactly what keeps the two tables consistent with each other. …

The rule is about matching values, not about the field names being identical. Also note the one nuance: a foreign key may be left blank where the design all …