#MySQL #tutorial #course

00:00:00 intro
00:02:24 SET NULL
00:04:40 CASCADE
00:07:11 conclusion

ALTER TABLE transactions
ADD CONSTRAINT fk_customer_id
FOREIGN KEY (customer_id) REFERENCES customers(customer_id)
ON DELETE SET NULL;

ALTER TABLE transactions
ADD CONSTRAINT fk_customer_id
FOREIGN KEY (customer_id) REFERENCES customers(customer_id)
ON DELETE CASCADE;