Question

CREATE TABLE `recipe` (
  `ID` int(11) NOT NULL AUTO_INCREMENT,
  `ethnicityID` int(25) NOT NULL,
  `recipename` varchar(225) COLLATE utf8_unicode_ci NOT NULL,
  `recipedescription` text COLLATE utf8_unicode_ci NOT NULL,
  `recipeprocedure` text COLLATE utf8_unicode_ci NOT NULL,
  `recipepremium` enum('YES','NO') COLLATE utf8_unicode_ci NOT NULL DEFAULT 'NO',
  `recipeusercreator` enum('YES','NO') COLLATE utf8_unicode_ci NOT NULL DEFAULT 'NO',
  `recipecreatorname` varchar(50) COLLATE utf8_unicode_ci NOT NULL,
  `recipeapprovedby` varchar(50) COLLATE utf8_unicode_ci NOT NULL,
  `recipeapproveddate` timestamp NULL DEFAULT NULL,
  `recipestatus` enum('YES','NO') COLLATE utf8_unicode_ci NOT NULL DEFAULT 'NO',
  `reciperequiresAdultSupervision` enum('YES','NO') COLLATE utf8_unicode_ci NOT NULL DEFAULT 'NO',
  `category_id` int(12) DEFAULT NULL,
  `facebookID` varchar(100) COLLATE utf8_unicode_ci NOT NULL,
  `recipetype` varchar(25) COLLATE utf8_unicode_ci NOT NULL,
  `language` varchar(225) COLLATE utf8_unicode_ci NOT NULL,
  `app` varchar(255) COLLATE utf8_unicode_ci DEFAULT NULL,
  `added_on` timestamp NOT NULL DEFAULT CURRENT_TIMESTAMP ON UPDATE CURRENT_TIMESTAMP,
  PRIMARY KEY (`ID`),
  KEY `fbID` (`facebookID`),
  KEY `foreignkey_PerCategory` (`category_id`)
) ENGINE=InnoDB AUTO_INCREMENT=19 DEFAULT CHARSET=utf8 COLLATE=utf8_unicode_ci;

这是我的MySQL表的表格语法。

当我尝试运行此查询时

DELETE FROM `recipe` WHERE `ID` IN ('12','13','14','15','16','17','18');

我收到以下错误

Cannot delete or update a parent row: a foreign key constraint fails (`desifoodapp`.`recipe_image`, CONSTRAINT `recipe_image_ibfk_1` FOREIGN KEY (`recipe_id`) REFERENCES `recipe` (`ID`) ON DELETE NO ACTION ON UPDATE CASCADE)

我想知道如何更正我的表格，以便删除配方时，也会从recipe_image表中删除它的图像，但不会删除配方所属的类别。它没有受到影响。

下面的recipe_image表

CREATE TABLE `recipe_image` (
  `ID` int(11) NOT NULL AUTO_INCREMENT,
  `recipeimage` varchar(225) DEFAULT NULL,
  `recipe_id` int(12) DEFAULT NULL,
  PRIMARY KEY (`ID`),
  KEY `recipe_id` (`recipe_id`),
  CONSTRAINT `recipe_image_ibfk_1` FOREIGN KEY (`recipe_id`) REFERENCES `recipe` (`ID`) ON DELETE NO ACTION ON UPDATE CASCADE
) ENGINE=InnoDB AUTO_INCREMENT=23 DEFAULT CHARSET=latin1;

下面的类别表

CREATE TABLE `category` (
  `ID` int(11) NOT NULL AUTO_INCREMENT,
  `categoryname` varchar(225) NOT NULL,
  `categoryimage` varchar(225) NOT NULL,
  `facebookID` int(25) NOT NULL,
  `added_on` timestamp NOT NULL DEFAULT CURRENT_TIMESTAMP ON UPDATE CURRENT_TIMESTAMP,
  PRIMARY KEY (`ID`)
) ENGINE=InnoDB AUTO_INCREMENT=11 DEFAULT CHARSET=latin1;

Answer 1

也可以将其删除CASCADE并尝试

假设你有食谱表作为主，其他表只是喜欢。当您进行外键约束时，只需将它们设置为CASCADE Delete和CASCADE update 因此，无论何时在主表中进行更改，都将更新所有其他表。或者如果您删除主表中的一条记录，并检查所有外键链接并在所有客户记录中删除它们

在其他表定义中设置这些行

ON DELETE CASCADE ON UPDATE CASCADE

例如：recipre_image

CONSTRAINT `recipe_image_ibfk_1` FOREIGN KEY (`recipe_id`) REFERENCES `recipe` (`ID`) ON DELETE CASCADE ON UPDATE CASCADE

Answer 2

外键约束阻止您从表中删除内容。您必须进行级联删除或类似的操作：

SQL Server: Deleting Rows with Foreign Key Constraints: Can Transactions override the constraints?

Answer 3

当您要删除的表中的any field在另一个表中引用为foreign key并且引用的表中有任何条目时，您无法进行删除操作。

相反，您可以使用cascade删除操作删除表和字段引用表中的所有记录。或者您可以在要删除的表格上使用rule

有关级联删除操作，请参阅以下链接： Cascade Delete

无法从表中删除记录

3 个答案: