我正在根据 EER 模型 sql 脚本创建一个 mysql 数据库,并且在尝试进行转换时(全部在 MySQL Workbench 中),我收到上述错误。我的目标是从附件表(sent_from 和 from_to)中的 2 列中引用adoption_entity 表上的admission_entity_id。
我有两张表,其中一张是附件:
-- -----------------------------------------------------
-- Table `afth_db`.`attachment`
-- -----------------------------------------------------
DROP TABLE IF EXISTS `afth_db`.`attachment` ;
CREATE TABLE IF NOT EXISTS `afth_db`.`attachment` (
`attachment_id` BIGINT NOT NULL,
`sent_from` INT NULL,
`sent_to` INT NULL,
`attachment_description` LONGTEXT NULL,
`attachment_uploaded` DATETIME NULL,
`attachment_uploaded_by` VARCHAR(255) NULL,
`adoption_case_num` BIGINT NOT NULL,
PRIMARY KEY (`attachment_id`),
INDEX `fk_attachment_adoption_case1_idx` (`adoption_case_num` ASC) VISIBLE,
UNIQUE INDEX `attachment_id_UNIQUE` (`attachment_id` ASC) VISIBLE,
UNIQUE INDEX `adoption_case_num_UNIQUE` (`adoption_case_num` ASC) VISIBLE,
INDEX `fk_attachment_adoption_entity1_idx` (`sent_from` ASC, `sent_to` ASC) VISIBLE,
UNIQUE INDEX `sent_to_UNIQUE` (`sent_to` ASC) VISIBLE,
UNIQUE INDEX `sent_from_UNIQUE` (`sent_from` ASC) VISIBLE,
CONSTRAINT `fk_attachment_adoption_case1`
FOREIGN KEY (`adoption_case_num`)
REFERENCES `afth_db`.`adoption_case` (`case_num`)
ON DELETE NO ACTION
ON UPDATE NO ACTION,
CONSTRAINT `fk_attachment_adoption_entity1`
FOREIGN KEY (`sent_from` , `sent_to`)
REFERENCES `afth_db`.`adoption_entity` (`adoption_entity_id` , `adoption_entity_id`)
ON DELETE NO ACTION
ON UPDATE NO ACTION)
ENGINE = InnoDB
另一个是收养实体:
-- -----------------------------------------------------
-- Table `afth_db`.`adoption_entity`
-- -----------------------------------------------------
CREATE TABLE IF NOT EXISTS `afth_db`.`adoption_entity` (
`adoption_entity_id` INT NOT NULL,
`adoption_entity_type` VARCHAR(255) NULL,
PRIMARY KEY (`adoption_entity_id`),
UNIQUE INDEX `adoption_entity_id_UNIQUE` (`adoption_entity_id` ASC) VISIBLE)
ENGINE = InnoDB
错误详细说明:
Operation failed: There was an error while applying the SQL script to the database.
ERROR 1822: Failed to add the foreign key constraint. Missing index for constraint 'fk_attachment_adoption_entity1' in the referenced table 'adoption_entity'
我不知道为什么它一直给我这个问题。我已经尝试了几种解决方案,从设置类型到“唯一索引”、“索引”为 fk_attachment_adoption_entity1 以及涉及的其他列,但我似乎无法摆脱错误。我也尝试删除并重新创建 1-1 关系,但这也无济于事。谁能告诉我我在 EER 模型设计方面是否做错了什么?
答案 0 :(得分:1)
您正在尝试创建一个外键引用,该引用跨越 sent_from
和 sent_to
两列到 adoption_entity
表中的单行。那不是你想要的。您希望为各个列 sent_from
和 sent_to
创建两个单独的外键引用。所以约束部分应该是这样的:
CONSTRAINT `fk_attachment_adoption_entity_from`
FOREIGN KEY (`sent_from`)
REFERENCES `afth_db`.`adoption_entity` (`adoption_entity_id`)
ON DELETE NO ACTION
ON UPDATE NO ACTION),
CONSTRAINT `fk_attachment_adoption_entity_to`
FOREIGN KEY (`sent_to`)
REFERENCES `afth_db`.`adoption_entity` (`adoption_entity_id`)
ON DELETE NO ACTION
ON UPDATE NO ACTION)