Mysql复合密钥从外部复合密钥中删除

我试图在Mysql WorkBench中的两个表之间建立多对多关系，其中一个表有一个复合主键（部分来自两个外键）。当我尝试生成SQL时，出现以下错误：

错误：错误1215:无法添加外键约束

SQL代码：

    -- -----------------------------------------------------
    -- Table `A_D_schema`.`Resources_has_OwnerGroups`
    -- -----------------------------------------------------
    CREATE TABLE IF NOT EXISTS `A_D_schema`.`Resources_has_OwnerGroups` (
      `Resources_id` INT NOT NULL,
      `OwnerGroups_id` INT NOT NULL,
      `OwnerGroups_Instances_has_Customers_Instances_idInstances` INT NOT NULL,
      `OwnerGroups_Instances_has_Customers_Customers_idCustomers` INT NOT NULL,
      PRIMARY KEY (`Resources_id`, `OwnerGroups_id`, `OwnerGroups_Instances_has_Customers_Instances_idInstances`, `OwnerGroups_Instances_has_Customers_Customers_idCustomers`),
      INDEX `fk_Resources_has_OwnerGroups_OwnerGroups1_idx` (`OwnerGroups_id` ASC, `OwnerGroups_Instances_has_Customers_Instances_idInstances` ASC, `OwnerGroups_Instances_has_Customers_Customers_idCustomers` ASC),
      INDEX `fk_Resources_has_OwnerGroups_Resources1_idx` (`Resources_id` ASC),
      CONSTRAINT `fk_Resources_has_OwnerGroups_Resources1`
        FOREIGN KEY (`Resources_id`)
        REFERENCES `A_D_schema`.`Resources` (`id`)
        ON DELETE NO ACTION
        ON UPDATE NO ACTION,
      CONSTRAINT `fk_Resources_has_OwnerGroups_OwnerGroups1`
        FOREIGN KEY (`OwnerGroups_id` , `OwnerGroups_Instances_has_Customers_Instances_idInstances` , `OwnerGroups_Instances_has_Customers_Customers_idCustomers`)
        REFERENCES `A_D_schema`.`OwnerGroups` (`id` , `Instances_has_Customers_Instances_idInstances` , `Instances_has_Customers_Customers_idCustomers`)
        ON DELETE NO ACTION
        ON UPDATE NO ACTION)
    ENGINE = InnoDB

从显示引擎INNODB状态的

中，我可以看到以下消息：

Cannot resolve column name close to:
)
    ON DELETE NO ACTION
    ON UPDATE NO ACTION,
  CONSTRAINT `fk_Resources_has_OwnerGroups_OwnerGroups1`
    FOREIGN KEY (`OwnerGroups_id` , `OwnerGroups_Instances_has_Customers_Instances_idInstances` , `OwnerGroups_Instances_has_Customers_Customers_idCustomers`)
    REFERENCES `A_D_schema`.`OwnerGroups` (`id` , `Instances_has_Customers_Instances_idInstances` , `Instances_has_Customers_Customers_idCustomers`)
    ON DELETE NO ACTION
    ON UPDATE NO ACTION)
ENGINE = InnoDB

显示创建表资源
和
显示创建表所有者组
：

CREATE TABLE `Resources` (
  `idResources` int(11) NOT NULL AUTO_INCREMENT,
  `email` varchar(45) DEFAULT NULL,
  `role` int(11) DEFAULT NULL COMMENT 'role : 1 disptcher \n0 admin',
  PRIMARY KEY (`idResources`),
  UNIQUE KEY `idresources_UNIQUE` (`idResources`)
) ENGINE=InnoDB DEFAULT CHARSET=latin1;

CREATE TABLE `OwnerGroups` (
  `idOwnerGroups` int(11) NOT NULL AUTO_INCREMENT,
  `name` varchar(45) DEFAULT NULL,
  `group` int(11) DEFAULT NULL,
  PRIMARY KEY (`idOwnerGroups`)
) ENGINE=InnoDB DEFAULT CHARSET=latin1;

您的资源表没有列
id
。它的主键是
idResources

  CONSTRAINT `fk_Resources_has_OwnerGroups_OwnerGroups1`
    FOREIGN KEY (`OwnerGroups_id` , `OwnerGroups_Instances_has_Customers_Instances_idInstances` , `OwnerGroups_Instances_has_Customers_Customers_idCustomers`)
    REFERENCES `A_D_schema`.`OwnerGroups` (`id` , `Instances_has_Customers_Instances_idInstances` , `Instances_has_Customers_Customers_idCustomers`)

您的OwnerGroups表没有列
id
。它的主键是
idOwnerGroups
。它根本没有您引用的其他两列


通常，在声明外键时，首先要命名子表中的列：

CREATE TABLE Child (
  childCol1 INT,
  childCol2 INT,
...
FOREIGN KEY (childCol1, childCol2) ...

然后引用父表中的列：

... REFERENCES Parent (parentCol1, parentCol2)
);

CREATE TABLE Parent (
  parentCol1 INT,
  parentCol2 INT,
  PRIMARY KEY (parentCol1)
);

必须使用父表中的列名称

父表中引用的列必须同时是该表的主键或唯一键。换句话说，鉴于上述示例，它不适用于此父表：

... REFERENCES Parent (parentCol1, parentCol2)
);

CREATE TABLE Parent (
  parentCol1 INT,
  parentCol2 INT,
  PRIMARY KEY (parentCol1)
);

因为主键不包括parentCol2


在您的情况下，以下各项应起作用：

CREATE TABLE IF NOT EXISTS `A_D_schema`.`Resources_has_OwnerGroups` (
  `Resources_id` INT NOT NULL,
  `OwnerGroups_id` INT NOT NULL,
  `OwnerGroups_Instances_has_Customers_Instances_idInstances` INT NOT NULL,
  `OwnerGroups_Instances_has_Customers_Customers_idCustomers` INT NOT NULL,
  PRIMARY KEY (`Resources_id`, `OwnerGroups_id`, `OwnerGroups_Instances_has_Customers_Instances_idInstances`, `OwnerGroups_Instances_has_Customers_Customers_idCustomers`),
  CONSTRAINT `fk_Resources_has_OwnerGroups_Resources1`
    FOREIGN KEY (`Resources_id`)
    REFERENCES `A_D_schema`.`Resources` (`idResources`)
    ON DELETE NO ACTION
    ON UPDATE NO ACTION,
  CONSTRAINT `fk_Resources_has_OwnerGroups_OwnerGroups1`
    FOREIGN KEY (`OwnerGroups_id`)
    REFERENCES `A_D_schema`.`OwnerGroups` (`idOwnerGroups`)
    ON DELETE NO ACTION
    ON UPDATE NO ACTION
) ENGINE = InnoDB

我拿出了两个冗余的索引定义。您不需要索引主键，它已经是表的聚集索引了。您不需要为外键声明中使用的列编制索引，MySQL将在需要时自动为该列编制索引（尽管如果该列已经存在索引，FK约束将使用该索引）

我不确定我是否理解您的另外两列
OwnerGroups\u Instances\u has\u Customers\u Instances\u idInstances
和
OwnerGroups\u Instances\u has\u Customers\u idCustomers
。通常在多对多表中，您只需要足够的列来引用相应父表的主键


请回复您的评论：

您应该不时尝试刷新架构的视图。在“模式”的右边有一个按钮，上面有一对弯曲的箭头

好的，谢谢你的评论。我注意到它来自世行。我将id命名为idResources，并将其重命名为id。但它仍然存在于脚本中。在左侧面板上，我甚至可以看到具有重复名称的表，这些表是我从…删除的。。。。我删除了资源\u拥有\u所有者组，它仍然存在于脚本中。WB被窃听了吗？所以如果我正确理解了你的评论，那么复合键的最佳实践是什么？假设对于表Resources\u has\u OwnerGroups：创建一个新的键Resources\u has\u OwnerGroups\u id，由fk\u Resources\u id和fk\u OwnerGroups\u id组成？
主键（Resources\u id，OwnerGroups\u id）
将是最佳实践。如果包含更多列，则允许前两列存在重复项。主键的成员是列，而不是FK约束。