Use the Patient and PersonName relationship I.e. : @person = PersonName.find_by_last_name Then a simple @person.patient will return the patient class object since rails knows the relationship. I would just include the first_name and last_name fields in the patient table. Having a seperate datafield to hold that little of info seems silly. You could use methods within the patient class to seperate the first_name and last_name data instead.