A FOREIGN KEY is a field (or collection of fields) in one table, that refers to the PRIMARY KEY in another table. The table with the foreign key is called the child table, and the table with the primary key is called the referenced or parent table.

A foreign key (FK) is a column or combination of columns that is used to establish and enforce a link between the data in two tables to control the data that can be stored in the foreign key table.

A FOREIGN KEY is a field (or group of fields) in one table that relates to the PRIMARY KEY in another. The table containing the foreign key is referred to as the child table, whereas the table containing the main key is referred to as the referenced or parent table.