Question

CREATE TABLE user
(userid INT(10), uname VARCHAR(30) NOT NULL, phone_num VARCHAR(10) NOT NULL, car_plate VARCHAR(9) NOT NULL,
PRIMARY KEY (userid));

INSERT INTO user (userid, uname, phone_num, car_plate)
VALUES (576, 'alvin', '81005199', 'sgu1256t'), (877, 'dominic', '97972841', 'sga8814e'), (112, 'desmond', '97551488', 'slj8422y');

CREATE TABLE carpark
(carparkid INT (10), location VARCHAR(35) NOT NULL,
PRIMARY KEY (carparkid));

INSERT INTO carpark (carparkid, location)
VALUES ('001', '25 toa payoh lorong 8'), ('002', '45 burghley drive'), ('003', 'ang mo kio hub');

CREATE TABLE lot
(carparkid INT(10) NOT NULL, lot_num INT(3) NOT NULL, lot_status ENUM('empty', 'reserved', 'occupied') DEFAULT 'empty');

INSERT INTO lot (carparkid, lot_num)
VALUES(001, 001), (001, 002), (001, 003), (001, 004), (001, 005), (002, 001), (002, 002), (002, 003), (002, 004), (002, 005), (003, 001), (003, 002), (003, 003), (003, 004), (003, 005);

到目前为止，这是我的代码，但是我需要将停车场中的carparkid改为停车场。当我使用这段代码时：

ALTER TABLE lot
ADD CONSTRAINT FK_carparklot
FOREIGN KEY (carparkid) REFERENCES carpark(carparkid)

它工作正常，但当我使用它时：

ALTER TABLE lot
ADD CONSTRAINT FK_carparklot
FOREIGN KEY (carparkid) REFERENCES carpark(carparkid)
ON DELETE CASCADE            
ON UPDATE SET DEFAULT;

它给了我错误：

ERROR 1005 (HY000): Can't create table `carparkful`.`#sql-3b64_3` (errno: 150 "Foreign key constraint is incorrectly formed")

Answer 1

按照InnoDB和NDB引擎的设计/文档操作。

根据DOCS：SET DEFAULT：MySQL解析器识别此操作，但 InnoDB和NDB拒绝包含 {{1}的表定义}或ON DELETE SET DEFAULT条款

这意味着不支持更新ON UPDATE SET DEFAULT选项/参数

ERROR 1005（HY000）：无法创建表`carparkful`。＃sql-3b64_3`（错误号：150＆＃34;外键约束形成错误＆＃34;）

1 个答案: