create table `produkt`  
 ( 
      `id` int unsigned not null auto_increment, 
      `oName` varchar(50) not null, 
      `ukName` varchar(50) not null, 
      `frmt` varchar(20) not null, 
      primary key(id), 
      foreign key (oName) REFERENCES oberflaeche(oName) on delete cascade, 
      foreign key (ukName) REFERENCES unterkonstruktion(ukName) on delete cascade, 
      foreign key (frmt) REFERENCES format(typ) on delete cascade 
 ) type=InnoDB;