title: What does "ptr" stand for in Django ORM column names?
body: <p>With these Django ORM models:</p>
  
  <pre><code>class A(Model):
      pass
  
  class B(A):
      pass
  </code></pre>
  
  <p>The table for <code>B</code> in the resulting schema contains the field:</p>
  
  <pre><code>"a_ptr_id" integer PRIMARY KEY
  </code></pre>
  
  <p>Just for the sake of better understanding Django's design choices - It there any rationale documentation that mentions what "ptr" signifies?</p>
  
  <p>My only guess is that it's an abbreviation for "pointer", but that seems pretty dumb since essentially <em>any</em> field with a foreign key constraint conceptually resembles a pointer.</p>