title: Generate unique id in django from a model field
body: <p>I want to generate different/unique id per request in django from models field. I did this but I keep getting the same id.</p>
  
  <pre><code>class Paid(models.Model):
       user=models.ForeignKey(User)
       eyw_transactionref=models.CharField(max_length=100, null=True, blank=True, unique=True, default=uuid.uuid4()) #want to generate new unique id from this field
  
       def __unicode__(self):
          return self.user
  </code></pre>