title: Understanding polymorphic associations the right way
body: <p>I've tried to set up a polymorphic association in an app, but when I test it out, I seem to be able to retreive my association only from one way:</p>
  
  <pre><code>class Event &lt; ActiveRecord::Base
    has_many :category_associations, :as =&gt; :categorized
  end
  
  class CategoryAssociation &lt; ActiveRecord::Base
    belongs_to :categorized, :polymorphic =&gt; true
  end
  </code></pre>
  
  <p>Now, in console, I created some CategoryAssociations (one being @ca ) and an Event ( @e ).
  I could then do</p>
  
  <pre><code>@ca.categorized = @e
  @ca.save
  </code></pre>
  
  <p>My problem is, if I load my event and try a <code>@e.category_associations</code> I get an empty array ... but when I try loading my @ca and do a <code>@ca.categorized</code>, I get my event !!</p>
  
  <p>Are polymorphic associations one way only ?
  Or what am I missing ?</p>