Which statement is correct?

Flat files use foreign keys to uniquely identify tables.

Flat files use foreign keys to secure data.

A foreign key is a primary key in another table.

A foreign key uniquely identifies a record in a table.

The correct answer is: A foreign key is a primary key in another table. I n the context of relational databases, a foreign key in one table uniquely identifies a row of another table or the same table. As such, it can be said to be a primary key in this table.