mysql add foreign key
-- On Create CREATE TABLE tableName ( ID INT, SomeEntityID INT, PRIMARY KEY (ID), FOREIGN KEY (SomeEntityID) REFERENCES SomeEntityTable(ID) ON DELETE CASCADE ); -- On Alter, if the column already exists but has no FK ALTER TABLE tableName ADD FOREIGN KEY (SomeEntityID) REFERENCES SomeEntityTable(ID) ON DELETE CASCADE; -- Add FK with a specific name -- On Alter, if the column already exists but has no FK ALTER TABLE tableName ADD CONSTRAINT fk_name FOREIGN KEY (SomeEntityID) REFERENCES SomeEntityTable(ID) ON DELETE CASCADE;