Create foreign key using phpMyAdmin

1. Select foreign key column in the table.
2. Select Action -> index -> ok
3. Now click on Relation View

Now add foreign key. 

Constraint option

1. CASCADE: If delete/update row in 'record' table it also delete row in linked table.
2. SET NULL:  If delete/update row in 'record' table it also set null in inked table.
3. NO ACTION: Nothing happened.
4. RESTRICT: Parent row can't be delete/update if child contain that reference. 

Caution

1. Both primary and foreign key have same datatype.