title: Django model accepts blank values for field defined as NOT NULL
body: <p><b> EDIT: I tried this out again after 3-4 weeks and I did not encounter this problem again. I'm not sure why. I was quite surprised that Django wasn't throwing up any NOT NULL constraint when I first encountered this problem. But now, when I tried it again after 3-4 weeks, it works fine. I'm not sure why.</p>
  
  <p>Anyway, this question is not really valid any more. </b></p>
  
  <p>I'm a Django newbie.</p>
  
  <p>My model has a class that has a couple of fields which are defined as NOT NULL.</p>
  
  <pre><code>class Post(models.Model):
      title = models.CharField(max_length=60)
      create_date=models.DateField(verbose_name='created Date')
  </code></pre>
  
  <p>When I go to the command line (through manage.py shell), and create a new Post instance by doing the following, Django saves the entry to the database:</p>
  
  <pre><code>p=Post(title='test')
  p.save()
  </code></pre>
  
  <p>Why doesn't it throw up an error like it does when I attempt the same from the Admin panel?</p>