title: Symfony2 & Doctrine2 PDOException without description
body: <p>I wanted to use this code, and it break on flush() without any exception message:</p>
  
  <pre><code>1. at PDOStatement -&gt;execute (null) 
  in ../vendor/doctrine-dbal/lib/Doctrine/DBAL/Statement.php at line 131    
  2. at Statement -&gt;execute () 
  in ../vendor/doctrine/lib/Doctrine/ORM/Persisters/BasicEntityPersister.php at line 237    
  3. at BasicEntityPersister -&gt;executeInserts () 
  in ../vendor/doctrine/lib/Doctrine/ORM/UnitOfWork.php at line 726    
  4. at UnitOfWork -&gt;executeInserts (object(ClassMetadata)) 
  in ../vendor/doctrine/lib/Doctrine/ORM/UnitOfWork.php at line 292    
  5. at UnitOfWork -&gt;commit () 
  in ../vendor/doctrine/lib/Doctrine/ORM/EntityManager.php at line 334    
  6. at EntityManager -&gt;flush () 
  in ../src/Tools/TFIBundle/Model/CSVImport.php at line 136    
  7. at CSVImport -&gt;addCategory ('fundusz obligacji') 
  in ../src/Tools/TFIBundle/Model/CSVImport.php at line 114
  </code></pre>
  
  <p>addCategory() method looks:</p>
  
  <pre><code>public function addCategory( $categoryName )
  {
      $category = new Category();
      $category-&gt;setName( $categoryName );
  
      $this-&gt;em-&gt;persist( $category );
      $this-&gt;em-&gt;flush();
      $this-&gt;counter['category']++;
  
      return $category;
  }
  </code></pre>
  
  <p>any idea what is wrong? or how to get PDOException message within symfony2 ?</p>