Can't create table with this script Trying to create a table with the script below. Every time I execute it I get the following error and can't work out why?!

#1064 - You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near ') ,
  CONSTRAINT cat_id
    FOREIGN KEY ()
    REFERENCES waitron.`catego' at line 7 **

CREATE  TABLE IF NOT EXISTS `waitron`.`dishes` (
      `dish_id` INT NOT NULL AUTO_INCREMENT ,
      `dish_name` VARCHAR(90) NULL ,
      `dish_desc` VARCHAR(200) NULL ,
      `price` DECIMAL(19,4) NULL ,
      PRIMARY KEY (`dish_id`) ,
      INDEX `cat_id` () ,
      CONSTRAINT `cat_id`
        FOREIGN KEY ()
        REFERENCES `waitron`.`categories` ()
        ON DELETE NO ACTION
        ON UPDATE NO ACTION)
    ENGINE = InnoDB;
The index you have named cat_id doesn't have any columns in it.  You must actually index something in your index.  The FOREIGN KEY () column list is also empty.  You must actual point at some foreign keys.