no se como restringir entrada de datos

[gralf]

tengo este esquema

Código MySQL:

SET @OLD_UNIQUE_CHECKS=@@UNIQUE_CHECKS, UNIQUE_CHECKS=0;
SET @OLD_FOREIGN_KEY_CHECKS=@@FOREIGN_KEY_CHECKS, FOREIGN_KEY_CHECKS=0;
SET @OLD_SQL_MODE=@@SQL_MODE, SQL_MODE='TRADITIONAL,ALLOW_INVALID_DATES';
 
CREATE SCHEMA IF NOT EXISTS `stocklentesbrujuleando` DEFAULT CHARACTER SET utf8 ;
USE `stocklentesbrujuleando` ;
 
-- -----------------------------------------------------
-- Table `stocklentesbrujuleando`.`cilindro`
-- -----------------------------------------------------
CREATE  TABLE IF NOT EXISTS `stocklentesbrujuleando`.`cilindro` (
  `ID_cil` INT(2) NOT NULL AUTO_INCREMENT ,
  `cilindro` DECIMAL(5,2) NOT NULL ,
  PRIMARY KEY (`ID_cil`) )
ENGINE = InnoDB
AUTO_INCREMENT = 18
DEFAULT CHARACTER SET = utf8;
 
 
-- -----------------------------------------------------
-- Table `stocklentesbrujuleando`.`esfera`
-- -----------------------------------------------------
CREATE  TABLE IF NOT EXISTS `stocklentesbrujuleando`.`esfera` (
  `ID_esf` INT(5) NOT NULL AUTO_INCREMENT ,
  `esfera` DECIMAL(5,2) NOT NULL ,
  PRIMARY KEY (`ID_esf`) )
ENGINE = InnoDB
AUTO_INCREMENT = 75
DEFAULT CHARACTER SET = utf8;
 
 
-- -----------------------------------------------------
-- Table `stocklentesbrujuleando`.`lentes`
-- -----------------------------------------------------
CREATE  TABLE IF NOT EXISTS `stocklentesbrujuleando`.`lentes` (
  `ID_lente` INT(2) NOT NULL AUTO_INCREMENT ,
  `lente` VARCHAR(25) NOT NULL ,
  `desc` VARCHAR(45) NOT NULL ,
  `Abbe` INT(2) NOT NULL ,
  `densidad` VARCHAR(15) NOT NULL ,
  `geometría` VARCHAR(15) NOT NULL ,
  PRIMARY KEY (`ID_lente`) ,
  UNIQUE INDEX `tipo` (`lente` ASC) )
ENGINE = InnoDB
AUTO_INCREMENT = 12
DEFAULT CHARACTER SET = utf8;
 
 
-- -----------------------------------------------------
-- Table `stocklentesbrujuleando`.`rx`
-- -----------------------------------------------------
CREATE  TABLE IF NOT EXISTS `stocklentesbrujuleando`.`rx` (
  `Id_Rx` INT(2) NOT NULL DEFAULT '0' ,
  `id_cil` INT(2) NOT NULL ,
  `id_esf` INT(5) NOT NULL ,
  PRIMARY KEY (`Id_Rx`) ,
  INDEX `fk_rx_cilindro1_idx` (`id_cil` ASC) ,
  INDEX `fk_rx_esfera1_idx` (`id_esf` ASC) ,
  CONSTRAINT `fk_rx_cilindro1`
    FOREIGN KEY (`id_cil` )
    REFERENCES `stocklentesbrujuleando`.`cilindro` (`ID_cil` )
    ON DELETE NO ACTION
    ON UPDATE NO ACTION,
  CONSTRAINT `fk_rx_esfera1`
    FOREIGN KEY (`id_esf` )
    REFERENCES `stocklentesbrujuleando`.`esfera` (`ID_esf` )
    ON DELETE NO ACTION
    ON UPDATE NO ACTION)
ENGINE = InnoDB
DEFAULT CHARACTER SET = utf8;
 
 
-- -----------------------------------------------------
-- Table `stocklentesbrujuleando`.`item`
-- -----------------------------------------------------
CREATE  TABLE IF NOT EXISTS `stocklentesbrujuleando`.`item` (
  `item_ID` INT(5) NOT NULL AUTO_INCREMENT ,
  `id_rx` INT(2) NOT NULL ,
  `id_lente` INT(2) NOT NULL ,
  PRIMARY KEY (`item_ID`) ,
  INDEX `fk_item_lentes1_idx` (`id_lente` ASC) ,
  INDEX `fk_item_rx1_idx` (`id_rx` ASC) ,
  CONSTRAINT `fk_item_lentes1`
    FOREIGN KEY (`id_lente` )
    REFERENCES `stocklentesbrujuleando`.`lentes` (`ID_lente` )
    ON DELETE NO ACTION
    ON UPDATE NO ACTION,
  CONSTRAINT `fk_item_rx1`
    FOREIGN KEY (`id_rx` )
    REFERENCES `stocklentesbrujuleando`.`rx` (`Id_Rx` )
    ON DELETE NO ACTION
    ON UPDATE NO ACTION)
ENGINE = InnoDB
DEFAULT CHARACTER SET = utf8;
 
 
-- -----------------------------------------------------
-- Table `stocklentesbrujuleando`.`movimiento`
-- -----------------------------------------------------
CREATE  TABLE IF NOT EXISTS `stocklentesbrujuleando`.`movimiento` (
  `id_mov` INT(5) UNSIGNED NOT NULL AUTO_INCREMENT ,
  `venta` INT(5) UNSIGNED NULL ,
  `compra` INT(5) UNSIGNED NULL ,
  `taller` INT(5) UNSIGNED NULL ,
  `regula_mas` INT(5) UNSIGNED NULL ,
  `regula_menos` INT(5) UNSIGNED NULL ,
  `fecha` TIMESTAMP NOT NULL ,
  `id_item` INT(5) NOT NULL ,
  `id_lente` INT(2) NULL ,
  `id_cilindro` INT(2) NULL ,
  `id_esfera` INT(5) NULL ,
  PRIMARY KEY (`id_mov`) ,
  INDEX `fk_salida_item1_idx` (`id_item` ASC) ,
  INDEX `fk_movimiento_lentes1_idx` (`id_lente` ASC) ,
  INDEX `fk_movimiento_cilindro1_idx` (`id_cilindro` ASC) ,
  INDEX `fk_movimiento_esfera1_idx` (`id_esfera` ASC) ,
  CONSTRAINT `fk_salida_item1`
    FOREIGN KEY (`id_item` )
    REFERENCES `stocklentesbrujuleando`.`item` (`item_ID` )
    ON DELETE NO ACTION
    ON UPDATE NO ACTION,
  CONSTRAINT `fk_movimiento_lentes1`
    FOREIGN KEY (`id_lente` )
    REFERENCES `stocklentesbrujuleando`.`lentes` (`ID_lente` )
    ON DELETE NO ACTION
    ON UPDATE NO ACTION,
  CONSTRAINT `fk_movimiento_cilindro1`
    FOREIGN KEY (`id_cilindro` )
    REFERENCES `stocklentesbrujuleando`.`cilindro` (`ID_cil` )
    ON DELETE NO ACTION
    ON UPDATE NO ACTION,
  CONSTRAINT `fk_movimiento_esfera1`
    FOREIGN KEY (`id_esfera` )
    REFERENCES `stocklentesbrujuleando`.`esfera` (`ID_esf` )
    ON DELETE NO ACTION
    ON UPDATE NO ACTION)
ENGINE = InnoDB
DEFAULT CHARACTER SET = utf8;
 
 
 
SET SQL_MODE=@OLD_SQL_MODE;
SET FOREIGN_KEY_CHECKS=@OLD_FOREIGN_KEY_CHECKS;
SET UNIQUE_CHECKS=@OLD_UNIQUE_CHECKS;
 

las tablas esfera, cilindro, rx, item, lentes pobladas.

ahora estoy probando la tabla movimientos y si intento introducir un item que no existe en la tabla item, este entra igual, cómo debería hacer para evitar esto?