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POActiveRecord requerying depending on order of operations
 

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    <p>New to Ruby and Rails so forgive me if my terminology is off a bit.</p> <p>I am working on optimizing some inherited code and watching the logs I am seeing queries repeat themselves due to lines like this in a .rabl file:</p> <pre class="lang-rb prettyprint-override"><code>node(:program) { |user| (!user.programs.first.nil?) ? user.programs.first.name : '' } </code></pre> <p><code>user</code> and <code>program</code> are both active record objects </p> <p>Moving to the rails console, I can replicate the problem, but I can also get the expected behavior, which is only one query:</p> <pre><code>&gt;u = User.find(1234) User Load (0.3ms) SELECT `users`.* FROM `users` WHERE [...] &gt; (!u.programs.first.nil?) ? u.programs.first.name : '' Program Load (0.2ms) SELECT `programs`.* FROM `programs` [...] Program Load (0.3ms) SELECT `programs`.* FROM `programs` [...] =&gt; "Output" </code></pre> <p>Note that repeating the ternary statement in the console will <em>always</em> give me 2 queries.</p> <p>I can get the expected behavior like so:</p> <pre><code>&gt; newu = User.find(12345) User Load (3.8ms) SELECT `users`.* FROM `users` WHERE [...] &gt; newu.programs Program Load (0.6ms) SELECT `programs`.* FROM `programs` [...] &gt; (!newu.programs.first.nil?) ? newu.programs.first.name : '' =&gt; "Output" </code></pre> <p>Repeating the ternary statement now won't requery at all.</p> <p>So the question is: why does calling <code>newu.programs</code> change the behavior? Shouldn't calling <code>u.programs.first.nil?</code> also act to load all the program records in the same way? </p>
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