JPQL HOWTO: "join" entities without foreign/primary keys?

Question

I have entities Person and Representative.
Entity Person has fields lastName, firstName and patronymic.
Entity Representative has field named title.
The task is:
Select all Persons and Representatives where representative.title contains Person.firstName, Person.lastName and person.patronymic.
Person can have several representatives.
Person and Representative don't have any keys. Is it possible to do it using JPQL or it's better to use native sql query?

Answer 1

I've tried something like this one:
public class PersonAndRepresentatives {
     private Person person;
     private List<Representative> representatives;
//my query:
                StringBuilder sb = new StringBuilder();
             sb.append("select new model.stateless.helperobject.PersonAndRepresentatives(p, repr) from Person p, Representative repr");
          sb.append(" where repr.title like p.firstName and repr.title like p.lastName");
          sb.append(" group by person.id");
          List<PersonAndRepresentatives> resultList = em.createQuery(sb.toString()).getResultList();But of course, I get exception on "*,*" which is here: "*from Person p, Representative repr*".
What can I do?
Seems like it's better to write native query and do not try to solve the problem using JPQL.