The Foregin Key constraint

The syntax to when creating a foreign key in [[The CREATE statement]]:

CREATE TABLE table_1 (
column_name data_type,
...
 FOREIGN KEY (column_name) REFERENCES table_2(column_name) ON DELETE CASCADE
);

The syntax when changing the foreign key in [[The ALTER statement]]:

ALTER TABLE table_1 
ADD FOREIGN KEY (column_name) REFERENCES table_2(column_name) ON DELETE CASCADE;

The syntax when dropping the foreign key constraint using the [[The DROP statement]]:

ALTER TABLE table_name
DROP FOREIGN KEY column_name [IN DDL SETTING];

Related constraints: [[The ON DELETE CASCADE constraint]]