title: DataNucleus - HashMultimap datastore created as mediumblob
body: <p>I am trying to use the type HashMultimap in one of my entity object.</p>
  
  <pre><code>@Persistent
  private HashMultimap&lt;String, String&gt; testMap;
  </code></pre>
  
  <p>JDO</p>
  
  <pre><code>&lt;field name="testMap" persistence-modifier="persistent" serialized="false"&gt;
      &lt;join /&gt;
  &lt;/field&gt;
  </code></pre>
  
  <p>However when i run schema tools with DataNuclues, the field is created as a mediumblob. My question is whether i can force this to be create as a join table.</p>
  
  <p>What i am after is basically a data type of a hashmap that can support duplicate key value.</p>
  
  <p>I am using MySQL as datastore</p>
  
  <p>Thanks</p>