外键和MySQL错误

Question

我有以下脚本在MySQL版本5.1中创建一个表，它引用其他3个表。所有3个表都是使用InnoDB创建的，并且所有3个表的ID列都定义为INT。

我已经成功地创建了引用ACCOUNT和PERSON的其他表，但是，这是第一个引用ADDRESS的表，因此我还在下面包含了该表的定义，如run。

我得到的错误是error 1005 (HY000)和errno150，据我所知这与外键创建有关。

失败的脚本为(为简单起见，删除了额外的列)：

CREATE TABLE WORK_ORDER (
    ID INT NOT NULL AUTO_INCREMENT PRIMARY KEY,
    ACCOUNT_ID INT NOT NULL,
    CUSTOMER_ID INT NOT NULL,
    SALES_ID INT,
    TRADES_ID INT,
    LOCATION_ID INT NOT NULL,
    INDEX CUST_INDEX(CUSTOMER_ID),
    INDEX SALES_INDEX(SALES_ID),
    INDEX TRADES_INDEX(TRADES_ID),
    INDEX ACCOUNT_INDEX(ACCOUNT_ID),
    INDEX LOCATION_INDEX(LOCATION_ID),
    FOREIGN KEY (CUSTOMER_ID) REFERENCES PERSON(ID) ON DELETE CASCADE,
    FOREIGN KEY (SALES_ID) REFERENCES PERSON(ID) ON DELETE SET NULL,
    FOREIGN KEY (TRADES_ID) REFERENCES PERSON(ID) ON DELETE SET NULL,
    FOREIGN KEY (ACCOUNT_ID) REFERENCES ACCOUNT(ID) ON DELETE CASCADE,
    FOREIGN KEY (LOCATION_ID) REFERENCES ADDRESS(ID) ON DELETE SET NULL
) ENGINE=InnoDB;

用于创建ADDRESS表的SQL语句如下(为简单起见，删除了额外的列)。

CREATE TABLE ADDRESS (
    ID INT NOT NULL AUTO_INCREMENT PRIMARY KEY,
    PERSON_ID INT NOT NULL,
    ACCOUNT_ID INT NOT NULL,
    ADDRESS_L1 VARCHAR(50),
    ADDRESS_L2 VARCHAR(50),
    CITY VARCHAR(25),
    PROVINCE VARCHAR(20),
    POSTAL_CODE VARCHAR(6),
    COUNTRY VARCHAR(25),
    INDEX CUST_INDEX(PERSON_ID),
    INDEX ACCOUNT_INDEX(ACCOUNT_ID),
    FOREIGN KEY (ACCOUNT_ID) REFERENCES ACCOUNT(ID) ON DELETE CASCADE,
    FOREIGN KEY (PERSON_ID) REFERENCES PERSON(ID) ON DELETE CASCADE
) ENGINE=InnoDB;

我在这里浏览了几个处理类似问题的问题，但大多数问题似乎是重复定义和不匹配的字段类型，以及一些表没有使用InnoDB。然而，这些似乎都不是问题所在。有什么想法吗？

Answer 1

您可以随时发出“SHOW ENGINE INNODB STATUS”命令。在输出中将隐藏一个“最新的外键错误”部分，它将提供有关导致'150‘错误的确切原因的更多细节：

mysql> create table a (x int not null) type=innodb;
Query OK, 0 rows affected, 1 warning (0.02 sec)

mysql> create table b (y int not null, foreign key (y) references a (x) on delete set null) type=innodb;
ERROR 1005 (HY000): Can't create table './test/b.frm' (errno: 150)

mysql> show engine innodb status;
[..... snip snip snip ...]
------------------------
LATEST FOREIGN KEY ERROR
------------------------
091129 16:32:41 Error in foreign key constraint of table test/b:
foreign key (y) references a (x) on delete set null) type=innodb:
You have defined a SET NULL condition though some of the
columns are defined as NOT NULL.
[.... snip snip snip ...]