title: Saving related model objects
body: <p>I have two related models (one to many) in my django app and When I do something like this</p>
  
  <pre><code>ObjBlog = Blog()
  objBlog.name = 'test blog'
  
  objEntry1 = Entry()
  objEntry1.title = 'Entry one'
  
  objEntry2 = Entry()
  objEntry2.title = 'Entry Two'
  
  objBlog.entry_set.add(objEntry1)
  objBlog.entry_set.add(objEntry2)
  </code></pre>
  
  <p>I get an error which says "null value in column and it violates the foreign key not null constraint". </p>
  
  <p>None of my model objects have been saved. Do I have to save the "objBlog" before I could set the entries? I was hoping I could call the save method on objBlog to save it all. </p>
  
  <p><strong><em>NOTE: I am not creating a blog engine and this is just an example.</em></strong></p>