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POHow do I do reflexive self-join relationships in ActiveRecord?
 

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  1. POHow do I do reflexive self-join relationships in ActiveRecord?
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    <p>I'm trying to implement a social networking style friendship model and I didnt have much much luck trying to figure out the plugins available out there. I think I'll learn Rails better if I do it myself. So here's what I have :</p> <pre><code>class User &lt; ActiveRecord::Base has_many :invitee_friendships , :foreign_key =&gt; :friend_id, :class_name =&gt; 'Friendship' has_many :inviter_friends, :through =&gt; :invitee_friendships has_many :inviter_friendships , :foreign_key =&gt; :user_id, :class_name =&gt; 'Friendship' has_many :invited_friends, :through =&gt; :inviter_friendships end class Friendship &lt; ActiveRecord::Base belongs_to :user //I think something needs to come here, i dont know what end </code></pre> <p>In <code>irb</code> when I try this:</p> <pre><code>friend1 = Friend.create(:name =&gt; 'Jack') friend2 = Friend.create(:name =&gt; 'John') bff = Friendship.create(:user_id =&gt;1, :friend_id =&gt; 2) f1.invited_friends </code></pre> <p>I get an error:</p> <pre><code>ActiveRecord::HasManyThroughSourceAssociationNotFoundError: Could not find the source association(s) :invited_friend or :invited_friends in model Friendship. Try 'has_many :invited_friends, :through =&gt; :invited_friendships, :source =&gt; &lt;name&gt;'. Is it one of :user? </code></pre> <p><strong>Expanation of friendship system:</strong></p> <ul> <li>A user can invite other users to become friends.</li> <li>Users who you invited to become friends are represented by <code>invited_friends</code>.</li> <li>Users who invited you to become friends are represented by <code>inviter_friends</code>.</li> <li>Your total friend list is represented by <code>invited_friends</code> + <code>inviter_friends</code>.</li> </ul> <p><strong>Schema</strong></p> <pre><code>table Friendship t.integer :user_id t.integer :friend_id t.boolean :invite_accepted t.timestamps table User t.string :name t.string :description </code></pre>
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    1. COwhat error do you get?
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    2. COjust added the error
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    3. COPls provide the complete schema. The plugin rake task Annotate Models -- http://pragdave.pragprog.com/pragdave/2006/02/annotate_models.html and http://agilewebdevelopment.com/plugins/annotate_models -- is very helpful for this. It documents the models' schemas as comments in the model files.
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      1. USLarry K
 

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