title: Entity to DTO conversion with JPA
body: <p>I'm using DataNucleus as a JPA implementation to store my classes in my web application.  I use a set of converters which all have <code>toDTO()</code> and <code>fromDTO()</code>.  </p>
  
  <p>My issue is, that I want to avoid the whole DB being sent over the wire:  </p>
  
  <ul>
  <li>If I lazy load, the converter will try to access ALL the fields, and load then (resulting in very eager loading).  </li>
  <li>If I don't lazy load, I'll get a huge part of the DB, since user contains groups, and groups contains users, and so on.</li>
  </ul>
  
  <p>Is there a way to explicitly load some fields and leave the others as NULL in my loaded class?
  I've tried the DataNucleus docs with no luck.  </p>