Question

我在尝试从mysql工作台转发工程师时收到错误'#1215 Cannot add foreign key'。

我有一个矩形表，它引用了scale和entities表中的列。 create rectangle语句抛出错误。

这是我的架构

-- -----------------------------------------------------
-- Table `newDb`.`Scales`
-- -----------------------------------------------------
CREATE TABLE IF NOT EXISTS `newDb`.`Scales` (
  `idScales` INT NOT NULL AUTO_INCREMENT,
  `scale_name` VARCHAR(100) NULL,
  `pid` INT NULL,
  `col_Id` INT NULL,
  `type` VARCHAR(45) NULL,
  `range_from` INT NULL,
  `range_to` INT NULL,
  `bandpadding` INT NULL,
  PRIMARY KEY (`idScales`),
  UNIQUE INDEX `idScales_UNIQUE` (`idScales` ASC),
  INDEX `pid_idx` (`pid` ASC),
  INDEX `col_id_idx` (`col_Id` ASC),
  CONSTRAINT `pid`
    FOREIGN KEY (`pid`)
    REFERENCES `newDb`.`projects` (`pid`)
    ON DELETE NO ACTION
    ON UPDATE NO ACTION,
  CONSTRAINT `col_id`
    FOREIGN KEY (`col_Id`)
    REFERENCES `newDb`.`data_sets_columns` (`col_Id`)
    ON DELETE NO ACTION
    ON UPDATE NO ACTION)
ENGINE = InnoDB;

-- -----------------------------------------------------
-- Table `newDb`.`Entities`
-- -----------------------------------------------------
CREATE TABLE IF NOT EXISTS `newDb`.`Entities` (
  `idEntities` INT NOT NULL AUTO_INCREMENT,
  `entity_name` VARCHAR(100) NULL,
  `entity_type` VARCHAR(45) NULL,
  `pid` INT NOT NULL,
  PRIMARY KEY (`idEntities`),
  UNIQUE INDEX `idEntities_UNIQUE` (`idEntities` ASC),
  INDEX `pid_idx` (`pid` ASC),
  CONSTRAINT `pidEF`
    FOREIGN KEY (`pid`)
    REFERENCES `newDb`.`projects` (`pid`)
    ON DELETE NO ACTION
    ON UPDATE NO ACTION)
ENGINE = InnoDB;


-- -----------------------------------------------------
-- Table `newDb`.`Rectangle`
-- -----------------------------------------------------
CREATE TABLE IF NOT EXISTS `newDb`.`Rectangle` (
  `idRectangle` INT NOT NULL AUTO_INCREMENT,
  `rect_name` VARCHAR(100) NULL,
  `X_pos` INT NOT NULL DEFAULT 0,
  `Y_pos` INT NOT NULL DEFAULT 0,
  `Height` INT NOT NULL DEFAULT 50,
  `Width` INT NOT NULL DEFAULT 50,
  `Offset_X` INT NOT NULL DEFAULT 0,
  `Offset_Y` INT NOT NULL DEFAULT 0,
  `Opacity` INT NULL DEFAULT 100,
  `Color` VARCHAR(10) NOT NULL DEFAULT 'black',
  `idScale` INT NOT NULL,
  `idEntities` INT NOT NULL,
  `idColorScale` INT NULL,
  PRIMARY KEY (`idRectangle`),
  UNIQUE INDEX `idRectangle_UNIQUE` (`idRectangle` ASC),
  INDEX `idScales_idx` (`idScale` ASC, `idColorScale` ASC),
  INDEX `idEntities_idx` (`idEntities` ASC),
  CONSTRAINT `idScalesF`
    FOREIGN KEY (`idScale` , `idColorScale`)
    REFERENCES `newDb`.`Scales` (`idScales` , `idScales`)
    ON DELETE RESTRICT
    ON UPDATE RESTRICT,
  CONSTRAINT `idEntitiesF`
    FOREIGN KEY (`idEntities`)
    REFERENCES `newDb`.`Entities` (`idEntities`)
    ON DELETE NO ACTION
    ON UPDATE NO ACTION)
ENGINE = InnoDB;

还有一个问题：MySQL Error 1215: Cannot add foreign key constraint要求同样的事情。

我跟着它，根据答案我要么发动机不匹配，列类型不匹配或列不匹配。

我似乎没有看到任何不匹配，因为我所有引用的列和外键coloum都是无符号的INT，名称相同，引擎是INNODB。

似乎无法找到我在这里缺少的东西

Answer 1

以下约束毫无意义：

CONSTRAINT `idScalesF`
  FOREIGN KEY (`idScale` , `idColorScale`)
  REFERENCES `newDb`.`Scales` (`idScales` , `idScales`)
  ON DELETE RESTRICT
  ON UPDATE RESTRICT,

这就像你在试图说Rectangle中的每一行都有一对idScale和idColorScale与Scales中的一对列相匹配这两个都叫idScales。如果您试图说idScale和idColorScale每个引用Scales中的一行，则需要将其写为两个单独的外键。

另外，PRIMARY KEY总是隐式唯一，并充当索引。您创建的…_UNIQUE索引（例如idScales_UNIQUE）都是多余的，应该删除。

无法添加外键＃1215

1 个答案: