Question

what is foreign key? ​

Answer 1

In the context of relational databases, 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 simple words ,the foreign key is defined in a second table , but it refers to the primary key or a uniqe key in the first table

Answer 2

Answer:

SQL FOREIGN KEY Constraint. A FOREIGN KEY is a key used to link two tables together. A FOREIGN KEY is a field (or collection of fields) in one table that refers to the PRIMARY KEY in another table. ... The FOREIGN KEY constraint is used to prevent actions that would destroy links between tables.