MySql 错误 1025

Question

我正在尝试在名为 ProductInvoice 的表中删除一个外键列。我要删除的列名为 PersonID，来自表 Person。当我运行查询时

ALTER TABLE ProductInvoice
DROP COLUMN PersonID;

我收到此错误...

Error Code: 1025. Error on rename of './jkripal/#sql-91c_19ff0' to './jkripal/ProductInvoice' (errno: 150)

关于如何解决此问题的任何建议？我环顾了这个网站，找不到任何有用的答案。

这些是 SHOW CREATE TABLE ProductInvoice 的结果

'ProductInvoice', 'CREATE TABLE `ProductInvoice` 
(\n  `ProductInvoiceID` int(11) NOT NULL AUTO_INCREMENT,
\n  `PersonID` int(11) DEFAULT NULL,
\n  `ProductID` int(11) NOT NULL,
\n  `InvoiceID` int(11) NOT NULL,
\n  `TravelDate` varchar(255) DEFAULT NULL,
\n  `TicketNote` varchar(255) DEFAULT NULL,
\n  `Quantity` int(11) DEFAULT NULL,
\n  `InsuranceTicketCode` varchar(255) DEFAULT NULL,
\n  PRIMARY KEY (`ProductInvoiceID`),
\n  KEY `fkPerson` (`PersonID`),
\n  KEY `fk_ProductInvoice_to_Product` (`ProductID`),
\n  KEY `fk_ProductInvoice_to_Invoice` (`InvoiceID`),
\n  CONSTRAINT `ProductInvoice_ibfk_1` FOREIGN KEY (`PersonID`) REFERENCES `Person` (`PersonID`),
\n  CONSTRAINT `ProductInvoice_ibfk_2` FOREIGN KEY (`ProductID`) REFERENCES `Product` (`ProductID`),
\n  CONSTRAINT `ProductInvoice_ibfk_3` FOREIGN KEY (`InvoiceID`) REFERENCES `Invoice` (`InvoiceID`)
\n) ENGINE=InnoDB AUTO_INCREMENT=4 DEFAULT CHARSET=utf8'

Answer 1

首先禁用外键

SET foreign_key_checks = 0;

删除 PersonID 上的键

ALTER TABLE ProductInvoice
  DROP INDEX fkPerson;

现在删除外键

ALTER TABLE ProductInvoice DROP FOREIGN KEY ProductInvoice_ibfk_1;

删除列

ALTER TABLE ProductInvoice DROP COLUMN PersonID;

启用外键：

SET foreign_key_checks = 1;

Answer 2

先删除Foreign key：

ALTER TABLE ProductInvoice DROP FOREIGN KEY ....;

然后：

ALTER TABLE ProductInvoice DROP COLUMN PersonID;