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POLoad several ActiveRecord models in one query
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  1. POLoad several ActiveRecord models in one query
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    copied!<p>My application is on Rails 2.</p> <p>I have 2 models, joined by a <code>has_and_belongs_to_many</code> relation : <code>Message</code> and <code>Conversation</code>. So I have 3 tables, <code>messages</code>, <code>conversations</code> and <code>conversations_messages</code>.</p> <p>Is it possible to load in one unique query both objects <code>Message</code> and <code>Conversation</code>, without using the <code>:include</code> option ? The <code>:include</code> option is impossible because my query depends of some external params.</p> <p>Example :</p> <p>I can do a query from Message to have a couple of (<code>Message</code>,<code>Conversation</code>) per line</p> <pre><code>messages = Message.find(:all, :select =&gt; "messages.*, conversations.*", :conditions =&gt; some_conditions_depending_of_external_variables :group =&gt; "messages.id" ) </code></pre> <p>The resulting table looks like :</p> <pre><code>`messages`.id | `messages`.field | `conversations`.id | `conversations`.field --------------+------------------+--------------------+------------------ 1 | ... | 10 | ... --------------+------------------+--------------------+------------------ 2 | ... | 15 | ... --------------+------------------+--------------------+------------------ 3 | ... | 10 | ... --------------+------------------+--------------------+------------------ 4 | ... | 20 | ... </code></pre> <p>After this query, my variable <code>messages</code> contains a set of AR Messages elements, but the conversations fields are not loaded as an AR Conversation.</p> <p>I want to be able to call a message.linked_conversation to have the conversation of the same line, as an AR object.</p> <p>Is there any method to do this without re-loading the objects ?</p>
 

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