classDiagram direction BT class airplanedata { varchar name integer capacity varchar id } class airport { varchar name varchar city varchar country varchar id } class customerdata { varchar firstname varchar lastname date dob varchar id } class flightdata { varchar routedatafrom varchar routedatatoo varchar etddatetime varchar etadatetime integer flightduration varchar airplaneid varchar id } class routedata { varchar fromm varchar too varchar id }
routedata --> flightdata : id