title: Why is related create() checking for id using Django ORM?
body: <p>I'm getting this error: </p>
  
  <pre><code>DETAIL:  Key (user_id)=(1) already exists.
  </code></pre>
  
  <p>when I run:</p>
  
  <pre><code>from records.models import Profile
  
  from django.contrib.auth.models import User
  
  users = User.objects.all()
      for user in users:
          p = Profile.objects.create(user=user)
  </code></pre>
  
  <p>I trying to create a profile for each of the existing users. </p>
  
  <p>Profile looks like this:</p>
  
  <pre><code>class Profile(models.Model):
      user = models.OneToOneField(User, on_delete=models.CASCADE)
      auto_complete_look_up_field = models.CharField(max_length=200,db_column='AutoCompleteLookUpField', blank=True, null=True)
  </code></pre>
  
  <p>What's happening here? I <em>would</em> expect that user_id to exist; that is the user I want to assign to Profile. Why is this even an error?</p>