Referential integrity is a data base concept indicating consistency between coupled tables. Referential integrity is enforced by the combination of a primary key and a foreign key. Within the data base design these keys are based upon the concept of ID fields.

For referential integrity to hold, any field in a table that is declared a foreign key can contain only values from a parent table's primary key or a candidate key. For instance, deleting a record that contains a value referred to by a foreign key in another table would break referential integrity.