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POHow to save data if you have two HABTM relations in a single model?
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copied!<p>I have altogether three models: User, Album and Genre. User refers to artist(singer, compose, musician etc). An album can have many artists(users) and many genres. An artist can compose/sing for many albums.In short I have following models and controller action . <strong>I have created two HABTM relations: albums_genres and users_albums in db.</strong></p> <pre><code>//User model class User < ActiveRecord::Base has_and_belongs_to_many :albums end //Album model class Album < ActiveRecord::Base has_and_belongs_to_many :genres has_and_belongs_to_many :users end //Genre model class Genre < ActiveRecord::Base has_and_belongs_to_many :albums end //albumController create method def create @user = current_user @album = @user.albums.new(params[:album]) if @album.save ... end end </code></pre> <p>When I send data as follows, data is inserted properly in albums_users. </p> <pre><code>"Album"=>{"title"=>"Test album", "description"=>"test description" </code></pre> <p>However I want insert data into albums_genres table as well. For this, my params data looks like:</p> <pre><code>"Album"=>{"title"=>"Test album", "description"=>"test description", "genre_ids"=>["1", "2", "3"]} </code></pre> <p>Then I got an error <strong>Can't mass-assign protected attributes: genre_ids</strong>. It's trying to insert data into albums table which I believe should insert genre_ids into albums_genres. So my question is how do i need to write controller code? Better way to write controller and/or model code is highly appreciated. Thank you in advance! Reference taken from: <a href="http://railscasts.com/episodes/17-habtm-checkboxes" rel="nofollow">http://railscasts.com/episodes/17-habtm-checkboxes</a></p>

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