title: Case sensitive search in Django, but ignored in Mysql
body: <p>I have a field in a Django Model for storing a unique (hash) value. Turns out that the database (MySQL/inno) doesn't do a case sensitive search on this type (VARCHAR), not even if I explicitly tell Django to do a case sensitive search <code>Document.objects.get(hash__exact="abcd123")</code>. So "abcd123" and "ABcd123" are both returned, which I don't want.   </p>
  
  <pre><code>class document(models.Model):
     filename    = models.CharField(max_length=120)
     hash        = models.CharField(max_length=33 )
  </code></pre>
  
  <p>I can change the 'hash field' to a BinaryField , so in the DB it becomes a LONGBLOB , and it does do a case-sensitive search (and works). However, this doesn't seem very efficient to me. 
  Is there a better way (in Django) to do this, like adding 'utf8 COLLATE'? or what would be the correct Fieldtype in this situation? 
  (yes, I know I could use PostgreSQL instead..)   </p>