mysql - 是否可以在 mysql 中向复合键添加外键约束？

Question

所以我有 2 个表。

主题时间表:

CREATE TABLE IF NOT EXISTS `subject_schedule` (
  `subject` varchar(10) NOT NULL,
  `schedule_id` int(11) NOT NULL,
  `id` int(11) NOT NULL,
  PRIMARY KEY (`subject`,`schedule_id`),
  KEY `schedule_id` (`schedule_id`)
) ENGINE=InnoDB DEFAULT CHARSET=latin1;

和约会:

CREATE TABLE IF NOT EXISTS `appointment` (
  `work_plan` varchar(1000) DEFAULT NULL,
  `date` date DEFAULT NULL,
  `homework_given` varchar(1000) DEFAULT NULL,
  `tutor_comments` varchar(1000) DEFAULT NULL,
  `admin_comments` varchar(1000) DEFAULT NULL,
  `id` int(11) NOT NULL AUTO_INCREMENT,
  `schedule_id` int(11) NOT NULL,
  `attended` tinyint(1) NOT NULL DEFAULT '1',
  `arrival_time` time DEFAULT NULL,
  `departure_time` time DEFAULT NULL,
  `homework_completed` tinyint(1) NOT NULL DEFAULT '0',
  `subject` varchar(10) NOT NULL,
  PRIMARY KEY (`id`),
  KEY `schedule_id` (`schedule_id`),
  KEY `subject` (`subject`)
) ENGINE=InnoDB  DEFAULT CHARSET=latin1 AUTO_INCREMENT=10004 ;

我想创建一个在约会中引用复合键的外键。我试过:

ALTER TABLE 'appointment'
ADD CONSTRAINT 'appointment_fk' FOREIGN KEY (`schedule_id`, `subject`) 
REFERENCES 'subject_schedule' ('schedule_id', 'subject');

但它在 PhpMyAdmin 中返回错误:

#1064 - You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near ''appointment' ADD CONSTRAINT 'appointment_fk' FOREIGN KEY (schedule_id, `su' at line 1

我做错了什么？仅将 id 作为主键并引用它而不是使用复合键是否更好？

Answer 1

columnNames 不应该用单引号引起来，因为它将被转换为字符串(不再是列)

ALTER TABLE appointment
ADD CONSTRAINT appointment_fk FOREIGN KEY (`schedule_id`, `subject`) 
REFERENCES subject_schedule (schedule_id, subject);

• SQLFiddle Demo