Alter Table Добавить внешний ключ MySQL
ALTER TABLE orders
ADD
FOREIGN KEY (user_id) REFERENCES users(id) ON DELETE CASCADE;
Beautiful Bug
ALTER TABLE orders
ADD
FOREIGN KEY (user_id) REFERENCES users(id) ON DELETE CASCADE; ALTER TABLE ordenes ADD ticket VARCHAR(50) NOT NULL;
ALTER TABLE ordenes ADD CONSTRAINT fk_ticket FOREIGN KEY (ticket) REFERENCES tickets(ticket);
ALTER TABLE `TABLE_NAME`
ADD COLUMN `COLUMN_NAME` BIGINT(20) UNSIGNED NULL DEFAULT NULL AFTER `AFTER_COLUMN_NAME`,
ADD FOREIGN KEY `FOREIGN_RELATION_NAME`(`COLUMN_NAME`) REFERENCES `FOREIGN_TABLE`(`FOREIGN_COLUMN`) ON UPDATE SET NULL ON DELETE SET NULL