CREATE TABLE product ( category INT NOT NULL, id INT NOT NULL, price DECIMAL, PRIMARY KEY(category, id) ) ENGINE=INNODB; CREATE TABLE customer ( id INT NOT NULL, PRIMARY KEY (id) ) ENGINE=INNODB; CREATE TABLE product_order ( no INT NOT NULL AUTO_INCREMENT, product_category INT NOT NULL, product_id INT NOT NULL, customer_id INT NOT NULL, PRIMARY KEY(no), INDEX (product_category, product_id), INDEX (customer_id), FOREIGN KEY (product_category, product_id) REFERENCES product(category, id) ON UPDATE CASCADE ON DELETE RESTRICT, FOREIGN KEY (customer_id) REFERENCES customer(id) ) ENGINE=INNODB;