title: Deletions with Spring data/Hibernate: ORA-01407: Cannot update to Null
body: <p>I am trying to delete rows in a certain table from my database using the <code>deleteAll()</code> method in the <a href="http://docs.spring.io/spring-data/commons/docs/current/api/org/springframework/data/repository/CrudRepository.html" rel="nofollow">CRUD Repository</a></p>
  
  <p>When I do so I get this error relating to my DOG table, row DOG_OWNER:</p>
  
  <pre><code>ORA-01407: Cannot update DOG_OWNER to Null
  </code></pre>
  
  <p>Is the fix just to remove the <code>not-null constraint</code> on this row, or is there another workaround?</p>