ErrorCode :1826 Duplicate foreign key constranit name 'college foreign key'那一段的代碼是：CREATE TABLE IF NOT EXISTS `jyjs161`.`homework` (? `id` INT NOT NULL AUTO_INCREMENT,? `title` VARCHAR(145) NULL,? `description` MEDIUMTEXT NULL,? `start_time` DATE NULL,? `end_time` DATE NULL,? `course_id` INT NULL,? PRIMARY KEY (`id`),? INDEX `course_foreign_key_idx` (`course_id` ASC) VISIBLE,? CONSTRAINT `course_foreign_key2`? ? FOREIGN KEY (`course_id`)? ? REFERENCES `jyjs161`.`course` (`id`)? ? ON DELETE NO ACTION? ? ON UPDATE NO ACTION)ENGINE = InnoDB;