mysql - 具有复合主键的外键

Question

一个表有一个列引用另一个表列，该列是复合主键。我该如何编写查询？它显示此错误。我该如何解决。

错误 1050:无法创建表“recdesk.#sql-5e8_33”(错误号:150)

SQL语句:

ALTER TABLE `recdesk`.`facility`
  CHANGE COLUMN `organization_id` `organization_id` INT(11) NOT NULL DEFAULT 0,
  CHANGE COLUMN `facility_id` `facility_id` INT(11) NOT NULL DEFAULT 0, 

  ADD CONSTRAINT `fk_organization_id`
  FOREIGN KEY (`organization_id` )
  REFERENCES `recdesk`.`facility_type` (`organization_id` )
  ON DELETE RESTRICT
  ON UPDATE RESTRICT, 

  ADD CONSTRAINT `fk_facility_type_id`
  FOREIGN KEY (`facility_type_id` )
  REFERENCES `recdesk`.`facility_type` (`facility_type_id` )
  ON DELETE RESTRICT
  ON UPDATE RESTRICT

, ADD INDEX `fk_organization_id_idx` (`organization_id` ASC) 
, ADD INDEX `fk_facility_type_id_idx` (`facility_type_id` ASC)


ERROR: Error when running failback script. Details follow.

ERROR 1050: Table 'facility' already exists

SQL Statement:

CREATE TABLE `facility` (
  `organization_id` int(11) NOT NULL,
  `facility_id` int(11) NOT NULL,
  `name` varchar(50) DEFAULT NULL,
  `address_line1` varchar(50) DEFAULT NULL,
  `address_line2` varchar(50) DEFAULT NULL,
  `city` varchar(30) DEFAULT NULL,
  `state` varchar(2) DEFAULT NULL,
  `zip_code` varchar(9) DEFAULT NULL,
  `description` varchar(1000) DEFAULT NULL,
  `note` varchar(250) DEFAULT NULL,
  `capacity` smallint(6) DEFAULT NULL,
  `show_on_portal` char(1) DEFAULT NULL,
  `active_indicator` char(1) DEFAULT NULL,
  `primary_facility_indicator` char(1) DEFAULT NULL,
  `facility_type_id` int(11) DEFAULT NULL,
  `parent_facility_id` int(11) DEFAULT NULL,
  `create_date` datetime DEFAULT NULL,
  `show_schedule_on_portal` char(1) DEFAULT NULL,
  `show_usage_on_portal` char(1) DEFAULT NULL,
  `enable_online_reservation` char(1) DEFAULT NULL,
  `gl_code_id` int(11) DEFAULT NULL,
  `gl_code_deposit_id` int(11) DEFAULT NULL,

  PRIMARY KEY (`organization_id`,`facility_id`)

) ENGINE=InnoDB DEFAULT CHARSET=latin1

Answer 1

如果 Facility 表中的 (Organization_ID, Facility_ID) 列对是对 (Organization_ID, Facility_ID) 列的外键引用 在表 Facility_Type 中，这是 Facility_Type 中的唯一键，那么您需要创建一个外键约束:

ALTER TABLE `recdesk`.`facility`
  CHANGE COLUMN `organization_id` `organization_id` INT(11) NOT NULL DEFAULT 0,
  CHANGE COLUMN `facility_id` `facility_id` INT(11) NOT NULL DEFAULT 0, 

  ADD CONSTRAINT `fk_facility_type`
  FOREIGN KEY (`organization_id`, `facility_type`)
  REFERENCES `recdesk`.`facility_type` (`organization_id`, `facility_type`)
  ON DELETE RESTRICT
  ON UPDATE RESTRICT, 

  ADD INDEX `fk_facility_type_idx` (`organization_id` ASC, `facility_type` ASC)

这是推断的语法，未经测试，但假设 MySQL 中没有禁止复合外键的意外限制，它应该接近您的需要。

这个概念是您需要一个单一的外键引用，它指定 Facility 表中的两列引用被引用表中的匹配列。索引也需要在一对列上，而不是在单个列上。