Answer :
Explanation :

Foreign keys are the columns of a table that points to the primary key of another table. They act as a cross-reference between tables.   In detail : A Foreign key is a field (or collection of fields) in one table that uniquely identifies a row of another table or the same table. In simpler words, the foreign key is defined in a second table, but it refers to the primary key or a unique key in the first table.