How do I check if something was eagerly loaded?

I’m looking for a way to check an item in memory to see if an
association loaded. I load the association in the controller and then
in the view I need to check to see if the associated model loaded
because I display an attribute of it. Of course, if the model didn’t
load, because it doesn’t exist, I get an error. For example, in my
controller I have thus:

def list
@systems = System.find(:all, :order => ‘name’, :include => :review)

:review belongs to a :system, which has_one :review

In my view I do this:
<%= link_to_if !,, :action => ‘edit’,
:id => %>

This doesn’t work, because it queries the database each time (I’m
looping through a collection of 200 items). So my question is, how can
I get the link_to_if to check the memory object of review, or is there a
different way to test this? I would think that I could just check
what’s in memory and not have to run another query for each item if I
already loaded all of them.