title: Are Value objects associations possible?
body: <p>I wonder whether it's possible to have relations between entities and value objects or if a third entity is mandatory as relation target. The purpose could be to flag different kind of entities with a common data structure that has it's own business logic. Any idea ?</p>
  
  <p>Update :</p>
  
  <p>Let's say I have a business object to model SCAP CPE namings :</p>
  
  <pre><code>&lt;?php
  
  namespace Scap\Cpe\Naming;
  
  /**
   * Cpe22 represents the naming convention in CPE Naming version 2.2
   * Accepted values are only CPE URIs
   */
  class Cpe22
  {
      protected $cpe;
  
      public function __construct($cpe)
      {
          if (! preg_match('/[c][pP][eE]:\/[AHOaho]?(:[A-Za-z0-9\._\-~%]*){0,6}/', $cpe)) {
              throw new InvalidNamingException();
          }
          $this-&gt;cpe = $cpe;
      }
  }
  </code></pre>
  
  <p>If I want to flag different kind of entities with this VO in a one-to-many way, I can think of 2 different ways :</p>
  
  <ul>
  <li>Entities are directly related to VOs so that the relation identifiers could be the entities references and the VOs themselves (= key composed from referenced identifier and representative VO fields)</li>
  <li>Entities are related to third entity types, that embed the VOs so that the relation identifiers are those third entities identifiers</li>
  </ul>
  
  <p>So I wonder if only the second option is available or if the first can somehow be implemented.</p>