title: Aggregate Objects
body: <p>If you have a class A that is an aggregate of class B and C, is it better for A</p>
  
  <ul>
  <li>to store ID's for B and C</li>
  <li>to load and store the entire object for B and C (edit, store by reference to object B/C, i.e. instantiate objects B and C as opposed to storing id's for B and C.</li>
  <li>store the ID's and provide methods to pull methods B and C</li>
  </ul>
  
  <p>I'm assuming this varies depending on performance requirements and other requierements, but I'm just looking for any general guidelines or thoughts.</p>