Mysql SQL模式级约束
我试图实现的一些表之间有一个约束,我想我应该在db级别上实现它,但我正在努力为google找到合适的术语,也许你们可以帮助我! 如果我有表格:Mysql SQL模式级约束,mysql,sql,constraints,Mysql,Sql,Constraints,我试图实现的一些表之间有一个约束,我想我应该在db级别上实现它,但我正在努力为google找到合适的术语,也许你们可以帮助我! 如果我有表格: 产品[可乐、香蕉、巧克力等] 产品类型[食品、饮料、化妆品等] 位置[冰箱、架子、橱柜等] 如果->是多对一,而>-产品类型 产品->位置 ProductType>-
- 产品[可乐、香蕉、巧克力等]
- 产品类型[食品、饮料、化妆品等]
- 位置[冰箱、架子、橱柜等]
- 产品->产品类型
- 产品->位置
- ProductType>-<位置
CREATE SCHEMA IF NOT EXISTS `test` DEFAULT CHARACTER SET utf8 COLLATE utf8_general_ci ;
USE `test` ;
-- -----------------------------------------------------
-- Table `test`.`Location`
-- -----------------------------------------------------
CREATE TABLE IF NOT EXISTS `test`.`Location` (
`id` INT NOT NULL AUTO_INCREMENT,
`name` VARCHAR(45) NULL,
PRIMARY KEY (`id`))
ENGINE = InnoDB;
-- -----------------------------------------------------
-- Table `test`.`ProductType`
-- -----------------------------------------------------
CREATE TABLE IF NOT EXISTS `test`.`ProductType` (
`id` INT NOT NULL AUTO_INCREMENT,
`name` VARCHAR(45) NULL,
PRIMARY KEY (`id`))
ENGINE = InnoDB;
-- -----------------------------------------------------
-- Table `test`.`Product`
-- -----------------------------------------------------
CREATE TABLE IF NOT EXISTS `test`.`Product` (
`id` INT NOT NULL AUTO_INCREMENT,
`name` VARCHAR(45) NULL,
`Location_id` INT NULL,
`ProductType_id` INT NOT NULL,
PRIMARY KEY (`id`),
INDEX `fk_Product_Location_idx` (`Location_id` ASC),
INDEX `fk_Product_ProductType1_idx` (`ProductType_id` ASC),
CONSTRAINT `fk_Product_Location`
FOREIGN KEY (`Location_id`)
REFERENCES `test`.`Location` (`id`)
ON DELETE NO ACTION
ON UPDATE NO ACTION,
CONSTRAINT `fk_Product_ProductType1`
FOREIGN KEY (`ProductType_id`)
REFERENCES `test`.`ProductType` (`id`)
ON DELETE NO ACTION
ON UPDATE NO ACTION)
ENGINE = InnoDB;
-- -----------------------------------------------------
-- Table `test`.`ProductType_has_Location`
-- -----------------------------------------------------
CREATE TABLE IF NOT EXISTS `test`.`ProductType_has_Location` (
`ProductType_id` INT NOT NULL,
`Location_id` INT NOT NULL,
PRIMARY KEY (`ProductType_id`, `Location_id`),
INDEX `fk_ProductType_has_Location_Location1_idx` (`Location_id` ASC),
INDEX `fk_ProductType_has_Location_ProductType1_idx` (`ProductType_id` ASC),
CONSTRAINT `fk_ProductType_has_Location_ProductType1`
FOREIGN KEY (`ProductType_id`)
REFERENCES `test`.`ProductType` (`id`)
ON DELETE NO ACTION
ON UPDATE NO ACTION,
CONSTRAINT `fk_ProductType_has_Location_Location1`
FOREIGN KEY (`Location_id`)
REFERENCES `test`.`Location` (`id`)
ON DELETE NO ACTION
ON UPDATE NO ACTION)
ENGINE = InnoDB;
INSERT INTO `test`.`Location`
(`name`)
VALUES
('fridge'),('shelf'),('cupboard');
INSERT INTO `test`.`ProductType`
(`name`)
VALUES
('food'),('drink'),('cosmetics');
INSERT INTO `test`.`ProductType_has_Location`
(`ProductType_id`,`Location_id`)
VALUES
(1,1),(2,1),(2,2),(3,3);
INSERT INTO `test`.`Product`
(`name`,`ProductType_id`,`Location_id`)
VALUES
('coke',2,NULL);
产品中的另一个约束条件是:
CONSTRAINT `fk_Product_Location_XRef`
FOREIGN KEY (`ProductType_id`,`Location_id`)
REFERENCES `test`.`ProductType_has_Location` (`ProductType_id`,`Location_id`)
ON DELETE NO ACTION
ON UPDATE NO ACTION
然后检查类型和位置是否与ProductType\u has\u Location
表中的内容一致。Aha,因此它有效地将(ProductType\u id,Location\u id)
视为唯一元组?@leontrolski-您已在ProductType\u has\u Location
表中声明了它们是唯一的-此处为主键(`ProductType\u id`、`Location\u id`)