sql错误错误号：121

Question

CREATE TABLE `users` (
  `UID` INT UNSIGNED NOT NULL AUTO_INCREMENT ,
  `username` VARCHAR(45) NOT NULL ,
  `password` VARCHAR(100) NULL ,
  `name` VARCHAR(100) NULL ,
  `gender` BIT NULL ,
  `email` VARCHAR(255) NULL ,
  `phone` VARCHAR(30) NOT NULL ,
  `verified` BIT NOT NULL DEFAULT 0 ,
  `time_zone` INT NULL ,
  `time_register` DATETIME NULL ,
  `time_active` DATETIME NULL ,
  PRIMARY KEY (`UID`) ,
  UNIQUE INDEX `username_UNIQUE` (`username` ASC) ,
  INDEX `verified_INDEX` (`verified` ASC) )
ENGINE = InnoDB
DEFAULT CHARACTER SET = utf8;


-- -----------------------------------------------------
-- Table `companies`
-- -----------------------------------------------------
CREATE TABLE `companies` (
  `CID` INT UNSIGNED NOT NULL AUTO_INCREMENT ,
  `name` VARCHAR(45) NOT NULL ,
  `address` VARCHAR(100) NULL ,
  `email` VARCHAR(255) NULL ,
  `phone` VARCHAR(30) NULL ,
  `link` TEXT NULL ,
  `image_small` TEXT NULL ,
  `image_large` TEXT NULL ,
  `yahoo` VARCHAR(100) NULL ,
  `linkin` VARCHAR(100) NULL ,
  `twitter` VARCHAR(20) NULL ,
  `description` TEXT NULL ,
  `shoutout` VARCHAR(140) NULL ,
  `verified` BIT NOT NULL DEFAULT 0 ,
  PRIMARY KEY (`CID`) ,
  INDEX `name_INDEX` (`name` ASC) ,
  INDEX `verified_INDEX` (`verified` ASC) )
ENGINE = InnoDB
DEFAULT CHARACTER SET = utf8;

-- -----------------------------------------------------
-- Table `products`
-- -----------------------------------------------------
CREATE TABLE `products` (
  `PID` INT UNSIGNED NOT NULL AUTO_INCREMENT ,
  `CID` INT UNSIGNED NOT NULL ,
  `name` VARCHAR(100) NULL ,
  `description` TEXT NULL ,
  `image_small` TEXT NULL ,
  `image_large` TEXT NULL ,
  `tag` VARCHAR(45) NULL ,
  `price` DECIMAL(11,2) NULL ,
  PRIMARY KEY (`PID`) ,
  INDEX `tag_INDEX` (`tag` ASC) ,
  INDEX `company.cid_FK` (`CID` ASC) ,
  CONSTRAINT `company.cid_FK`
    FOREIGN KEY (`CID` )
    REFERENCES `companies` (`CID` )
    ON DELETE NO ACTION
    ON UPDATE NO ACTION)
ENGINE = InnoDB
DEFAULT CHARACTER SET = utf8;

-- -----------------------------------------------------
-- Table `users_companies`
-- -----------------------------------------------------
CREATE TABLE `users_companies` (
  `UID` INT UNSIGNED NOT NULL ,
  `CID` INT UNSIGNED NOT NULL ,
  `role` INT UNSIGNED NULL ,
  PRIMARY KEY (`CID`, `UID`) ,
  INDEX `users.uid_FK` (`UID` ASC) ,
  INDEX `company.cid_FK` (`CID` ASC) ,
  CONSTRAINT `users.uid_FK`
    FOREIGN KEY (`UID` )
    REFERENCES `users` (`UID` )
    ON DELETE NO ACTION
    ON UPDATE NO ACTION,
  CONSTRAINT `company.cid_FK`
    FOREIGN KEY (`CID` )
    REFERENCES `companies` (`CID` )
    ON DELETE NO ACTION
    ON UPDATE NO ACTION)
ENGINE = InnoDB
DEFAULT CHARACTER SET = utf8;

我有错误

#1005 - Can't create table 'wew.users_companies' (errno: 121) (<a href="server_engines.php?engine=InnoDB&amp;page=Status&amp;token=3f35afdea97dd11f6b4ec1b669816738">Details...</a>) 

谁能告诉我是哪一个问题？

Answer 1

我得到了同样的错误 MySQL 错误代码 121: Duplicate key on write or update。

虽然我从数据库中删除了表以重新创建，但我不能，所以我用不同的约束重新创建了表。

我发现旧的约束仍然存在。

Answer 2

对于此类错误，您可以使用“perror”找到更多信息。即

shell $ perror 121

MySQL 错误代码 121：写入或更新时重复键
Win32错误代码121：信号量超时时间已过。

Answer 3

您有两个称为company.cid_FK 的约束。重命名一个。