无法在 mysql-workbench 上添加外键约束

Question

我正在尝试通过 mysql workbench 创建一个 table。我收到以下错误：-

错误 1215：无法添加外键约束 SQL 语句：

CREATE TABLE `propman`.`imageadassociation` (
  `ImageId` INT NOT NULL,
  `AdId` INT NOT NULL,
  INDEX `imageId_adassociation_idx` (`ImageId` ASC),
  INDEX `adId_adassociation_idx` (`AdId` ASC),
  CONSTRAINT `imageId_adassociation`
    FOREIGN KEY (`ImageId`)
    REFERENCES `propman`.`imagelocation` (`ImageId`)
    ON DELETE NO ACTION
    ON UPDATE NO ACTION,
  CONSTRAINT `adId_adassociation`
    FOREIGN KEY (`AdId`)
    REFERENCES `propman`.`advertisement` (`AdId`)
    ON DELETE NO ACTION
    ON UPDATE NO ACTION);

imageLocation table创建状态语句如下：-

CREATE TABLE `imagelocation` (
  `ImageId` int(11) NOT NULL,
  `ImageLocationcol` varchar(200) NOT NULL
) ENGINE=InnoDB DEFAULT CHARSET=utf8;

广告table的创建语句如下：-

CREATE TABLE `advertisement` (
  `AdId` int(10) NOT NULL AUTO_INCREMENT,
  `PropertyId` int(10) NOT NULL,
  `AdTemplateId` int(10) NOT NULL,
  `ValidFrom` date DEFAULT NULL,
  `ValidTo` date DEFAULT NULL,
  PRIMARY KEY (`AdId`),
  KEY `AdTemplateId` (`AdTemplateId`),
  CONSTRAINT `advertisement_ibfk_2` FOREIGN KEY (`AdTemplateId`) REFERENCES `adtemplate` (`AdTemplateId`)
) ENGINE=InnoDB AUTO_INCREMENT=7 DEFAULT CHARSET=utf8;

Answer 1

imageadassociation 是引用 table。表 imagelocation 和 advertisement 是 referenced tables.

被引用的2列需要满足条件：

来自 Using Foreign Key Constraints 上的 Mysql 手册页：

Corresponding columns in the foreign key and the referenced key must have similar data types. The size and sign of integer types must be the same. The length of string types need not be the same. For nonbinary (character) string columns, the character set and collation must be the same.

并且他们需要在 referenced table 中有最左边的索引。不满足这些条件。特别是 imageId

上没有索引

显示宽度并不重要（即：int(11)）

无法在 mysql-workbench 上添加外键约束

Cannot add foreign key constraint on mysql-workbench

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