title: Jpa composite key nullable columns
body: <p>I'm using Hibernate's JPA impl to model some tables. I'm having trouble mapping a table that:</p>
  
  <ul>
  <li>Has no primary key</li>
  <li>Has a unique index on 4 columns, 3 of which can be nullable</li>
  </ul>
  
  <p>I tried to hack it and define the index as a composite Id, but since some columns are nullable this is not working properly. Is this possible with JPA/Hibernate?</p>
  
  <p>Thanks</p>