MySQL 5.5添加外键失败,错误[HY000] [150]和[HY000] [1005]

Question

我试过像这样添加一个外键......

ALTER TABLE OrderLineItem
ADD CONSTRAINT
        FK_OrderLineItem_ShippingType_name FOREIGN KEY
(shippingType)
REFERENCES ShippingType(name);

或者在Mysql 5.5中这样...

alter table OrderLineItem add foreign key 
FK_OrderLineItem_ShippingType (shippingType) references ShippingType(name);

每次我看到以下错误.

[2011-11-18 15:07:04] [HY000] [150]使用外键约束创建表'realtorprint_dev_dev/#sql-7d0_80'失败.引用的表中没有索引,其中引用的列显示为第一列.

[2011-11-18 15:07:04] [HY000] [1005]无法创建表'realtorprint_dev_dev.#sql-7d0_80'(错误号:150)

OrderLineItem.shippingType和ShippingType.name都具有varchar(50)类型,而不是null.ShippingType.name是ShippingType的primaryKey.

以下是关于ShippingType以及OrderLineItem的show create table的结果...

CREATE TABLE `shippingtype` (
  `name` varchar(50) CHARACTER SET latin1 NOT NULL DEFAULT '',
  `description` varchar(255) CHARACTER SET latin1 NOT NULL,
  PRIMARY KEY (`name`)
) ENGINE=InnoDB DEFAULT CHARSET=utf8;

CREATE TABLE `orderlineitem` (
  `id` bigint(20) NOT NULL AUTO_INCREMENT,
  `description` varchar(255) CHARACTER SET latin1 NOT NULL,
  `lineNumber` int(11) NOT NULL,
  `quantity` int(11) NOT NULL,
  `quantityMultiplier` int(11) NOT NULL,
  `unitPrice` decimal(10,2) NOT NULL,
  `order_id` bigint(20) NOT NULL,
  `productDefinition_id` bigint(20) NOT NULL,
  `mlsId` varchar(255) CHARACTER SET latin1 DEFAULT NULL,
  `printProviderUnitCost` decimal(10,2) NOT NULL,
  `shippingType` varchar(50) NOT NULL,
  `address` varchar(255) DEFAULT NULL,
  `zipPostal` varchar(255) NOT NULL,
  `city` varchar(255) NOT NULL,
  `stateProvince` varchar(255) NOT NULL,
  `country` varchar(255) DEFAULT NULL,
  PRIMARY KEY (`id`),
  KEY `idx_OrderLineItem_productDefinition_id` (`productDefinition_id`),
  KEY `idx_OrderLineItem_order_id` (`order_id`),
  CONSTRAINT `FK_OrderLineItem_order_id` FOREIGN KEY (`order_id`) REFERENCES `userorder` (`id`),
  CONSTRAINT `FK_OrderLineItem_productDefinition_id` FOREIGN KEY (`productDefinition_id`) REFERENCES `productdefinition` (`id`)
) ENGINE=InnoDB AUTO_INCREMENT=10029 DEFAULT CHARSET=utf8;

Answer 1

当列类型不完全匹配时,Mysql可能会出现这个错误的错误 - 检查整理/大小等.

Answer 2

orderLineItem.shippingType有字符集utf8,但ShippingType.name有字符集latin1.这些与外键引用的目的不兼容.