table 中的重复键与 sql 中的外键

Question

我正在使用 mysql_workbench 创建数据库，我有 products_types、categories 和 subcategories table。 category_id 和 subcategory_id 分别是引用 categories 和 subcategories table 的外键。当我 forward engineer 这个模型从 workbench 到 mysql database on phpMyAdmin 时，它给出错误

Can't write; duplicate key in table 'product_types'

这是包含错误的准确代码。

Executing SQL script in server
ERROR: Error 1022: Can't write; duplicate key in table 'product_types'
SQL Code:
        -- -----------------------------------------------------
        -- Table `argo_project_01_2`.`product_types`
        -- -----------------------------------------------------
        CREATE TABLE IF NOT EXISTS `argo_project_01_2`.`product_types` (
          `id` INT NOT NULL,
          `category_id` INT NULL,
          `subcategory_id` INT NULL,
          `title` VARCHAR(100) NULL,
          `description` TEXT NULL,
          `status` INT NULL DEFAULT 0,
          `created` TIMESTAMP NULL DEFAULT CURRENT_TIMESTAMP,
          `modified` TIMESTAMP NULL,
          PRIMARY KEY (`id`),
          INDEX `category_id_idx` (`category_id` ASC),
          INDEX `subcategory_id_idx` (`subcategory_id` ASC),
          CONSTRAINT `category_id`
            FOREIGN KEY (`category_id`)
            REFERENCES `argo_project_01_2`.`categories` (`id`)
            ON DELETE NO ACTION
            ON UPDATE NO ACTION,
          CONSTRAINT `subcategory_id`
            FOREIGN KEY (`subcategory_id`)
            REFERENCES `argo_project_01_2`.`subcategories` (`id`)
            ON DELETE NO ACTION
            ON UPDATE NO ACTION)
        ENGINE = InnoDB

SQL script execution finished: statements: 9 succeeded, 1 failed

Fetching back view definitions in final form.
Nothing to fetch

查询有什么问题？

Answer 1

我认为可以通过将约束名称 "category_id" 和 "subcategory_id" 更改为例如 "fk_category_id" 和 "fk_subcategory_id" 来解决问题。

编辑：您也可以删除 "category_id_idx" 和 "subcategory_id_idx" 索引，因为外键会自动生成一个索引。

table 中的重复键与 sql 中的外键

duplicate key in table for foreign key in sql

mysql

sql-server

foreign-key-relationship