title: SQL - error code 1005 with error number 121
body: <p>I'm running the following MySQL query (trimmed down), generated automatically by <em>MySQL Workbench</em> and I get the following error:</p>
  <blockquote>
  <p>Error Code: 1005
  Can't create table 'regula.reservation' (errno: 121)</p>
  </blockquote>
  <p>I'm not very proficient with databases and this error is not very informative.</p>
  <p>What is the problem here?</p>
  <pre><code>-- -----------------------------------------------------
  -- Table `regula`.`Users`
  -- -----------------------------------------------------
  DROP TABLE IF EXISTS `regula`.`Users` ;
  
  CREATE  TABLE IF NOT EXISTS `regula`.`Users` (
    `idUsers` INT UNSIGNED NOT NULL AUTO_INCREMENT ,
    `name` TEXT NOT NULL ,
    `type` TEXT NOT NULL ,
    `pwd` TEXT NOT NULL ,
    PRIMARY KEY (`idUsers`) ,
    UNIQUE INDEX `idUsers_UNIQUE` (`idUsers` ASC) )
  ENGINE = InnoDB;
  
  
  -- -----------------------------------------------------
  -- Table `regula`.`Projects`
  -- -----------------------------------------------------
  DROP TABLE IF EXISTS `regula`.`Projects` ;
  
  CREATE  TABLE IF NOT EXISTS `regula`.`Projects` (
    `idProjects` INT UNSIGNED NOT NULL AUTO_INCREMENT ,
    `ownerId` INT UNSIGNED NOT NULL ,
    `name` TEXT NOT NULL ,
    `date` DATE NOT NULL ,
    `time` TIME NOT NULL ,
    `place` TEXT NOT NULL ,
    `itemType` INT NOT NULL ,
    PRIMARY KEY (`idProjects`) ,
    UNIQUE INDEX `idProjects_UNIQUE` (`idProjects` ASC) ,
    INDEX `ownerId` (`ownerId` ASC) ,
    CONSTRAINT `ownerId`
      FOREIGN KEY (`ownerId` )
      REFERENCES `regula`.`Users` (`idUsers` )
      ON DELETE NO ACTION
      ON UPDATE NO ACTION)
  ENGINE = InnoDB;
  
  
  -- -----------------------------------------------------
  -- Table `regula`.`ItemTypes`
  -- -----------------------------------------------------
  DROP TABLE IF EXISTS `regula`.`ItemTypes` ;
  
  CREATE  TABLE IF NOT EXISTS `regula`.`ItemTypes` (
    `idItemTypes` INT UNSIGNED NOT NULL ,
    `prjId` INT UNSIGNED NOT NULL ,
    `parentId` INT UNSIGNED NULL DEFAULT NULL ,
    `name` TEXT NOT NULL ,
    PRIMARY KEY (`idItemTypes`) ,
    INDEX `prjId` (`prjId` ASC) ,
    INDEX `parentId` (`parentId` ASC) ,
    CONSTRAINT `prjId`
      FOREIGN KEY (`prjId` )
      REFERENCES `regula`.`Projects` (`idProjects` )
      ON DELETE NO ACTION
      ON UPDATE NO ACTION,
    CONSTRAINT `parentId`
      FOREIGN KEY (`parentId` )
      REFERENCES `regula`.`ItemTypes` (`idItemTypes` )
      ON DELETE NO ACTION
      ON UPDATE NO ACTION)
  ENGINE = InnoDB;
  
  
  -- -----------------------------------------------------
  -- Table `regula`.`Reservation`
  -- -----------------------------------------------------
  DROP TABLE IF EXISTS `regula`.`Reservation` ;
  
  CREATE  TABLE IF NOT EXISTS `regula`.`Reservation` (
    `idReservation` INT UNSIGNED NOT NULL AUTO_INCREMENT ,
    `prjId` INT UNSIGNED NOT NULL ,
    `itemTypeId` INT UNSIGNED NOT NULL ,
    `userId` INT UNSIGNED NOT NULL ,
    PRIMARY KEY (`idReservation`) ,
    INDEX `prjId` (`prjId` ASC) ,
    INDEX `itemTypeId` (`itemTypeId` ASC) ,
    INDEX `userId` (`userId` ASC) ,
    CONSTRAINT `prjId`
      FOREIGN KEY (`prjId` )
      REFERENCES `regula`.`Projects` (`idProjects` )
      ON DELETE NO ACTION
      ON UPDATE NO ACTION,
    CONSTRAINT `itemTypeId`
      FOREIGN KEY (`itemTypeId` )
      REFERENCES `regula`.`ItemTypes` (`idItemTypes` )
      ON DELETE NO ACTION
      ON UPDATE NO ACTION,
    CONSTRAINT `userId`
      FOREIGN KEY (`userId` )
      REFERENCES `regula`.`Users` (`idUsers` )
      ON DELETE NO ACTION
      ON UPDATE NO ACTION)
  ENGINE = InnoDB;
  </code></pre>