MySQL 创建表：错误 1005 errno: 150 “外键约束的格式不正确”

Question

尝试创建 EXCHANGE 表时失败：

CREATE TABLE BOOK
(PKACC_NO VARCHAR (20) PRIMARY KEY,
TITLE VARCHAR (50),
AUTHOR VARCHAR (50),
PUBLISHER VARCHAR (50),
EDITION INTEGER (4),
PRICE INTEGER (10));

CREATE TABLE MEMBER
(PKMEMBER_ID VARCHAR (20) PRIMARY KEY,
NAME VARCHAR (50),
TYPE VARCHAR (10),
CONTACT_NO BIGINT (10),
ADHAAR_NO BIGINT(12),
LAST_VISIT DATE );

CREATE TABLE STAFF
(PKSTAFF_ID VARCHAR (20),
NAME VARCHAR(50),
ADHAAR_NO BIGINT (12),
CONTACT_NO BIGINT(10) );

CREATE TABLE EXCHANGE 
(TRANSACTION_ID VARCHAR(20) PRIMARY KEY,
FK1ACC_NO VARCHAR(20),
FK2MEMBER_ID VARCHAR (20),
FK3STAFF_ID VARCHAR(20),
DATE_OF_ISSUE DATE,
DATE_OF_RETURN DATE,
FINE INTEGER(20),
REMARKS VARCHAR(20),
CONSTRAINT FK1 FOREIGN KEY (FK1ACC_NO) REFERENCES BOOK (PKACC_NO)
ON DELETE CASCADE
ON UPDATE CASCADE,
CONSTRAINT FK2 FOREIGN KEY (FK2MEMBER_ID) REFERENCES MEMBER (PKMEMBER_ID)
ON DELETE CASCADE
ON UPDATE CASCADE,
CONSTRAINT FK3 FOREIGN KEY (FK3STAFF_ID) REFERENCES STAFF (PKSTAFF_ID)
ON DELETE CASCADE
ON UPDATE CASCADE);

最后一条 create 语句返回：

ERROR 1005 (HY000): Can't create table `testdb`.`EXCHANGE` (errno: 150 "Foreign key constraint is incorrectly formed")

Answer 1

有时，克服 InnoDB 表中错误的最佳方法是使用此命令检查 InnoDB 表状态。显示引擎 INNODB 状态；

这会让你明白你做错了什么。

Answer 2

问题是您忘记为 STAFF 表定义主键：

CREATE TABLE STAFF
(PKSTAFF_ID VARCHAR (20) PRIMARY KEY,
NAME VARCHAR(50),
ADHAAR_NO BIGINT (12),
CONTACT_NO BIGINT(10) );

一旦解决了这个问题，您就可以按照您的问题创建 EXCHANGE 表。