title: Django queries and joins
body: <p>I read in the Django documentation that in principle Django queries are lazy, that is the database is not queried until absolutely necessary. </p>
  
  <p>Now, as a matter of efficiency, when I retreive data via</p>
  
  <pre><code>FooModel.object.filter(...)
  </code></pre>
  
  <p>and I have defined a relationship between FooModel and BarModel, is the info from BarModel automatically retreived as well? Or does this only happen when I later reference any of the BarModel fields?</p>
  
  <p>On a related note. I have been looking for a simple way to somehow just confirm this for myself by looking at logs or using a debugger but have not been able to. I'd be interested in tips on how to do this.</p>