Rails 3 Data Modeling Help - Has Many, Belongs to, Nested Atrributes
I am working on a project involving three models (recipient, award, announcer) and need to have a nested attributes when issuing an award by an announcer to multiple recipients. For an example, award form need to have the ability to do 3 things:
- Can add multiple-recipients (i.e. "add 开发者_运维问答recipient", "remove recipient") - nested attributes
- After creating a new award, the award will be posted into recipient's profile.
- Enables future polling of @recipient.awards and @announcer.awards
Really struggle in terms of how to smartly solve this problem. The following data structure kind of made sense, however can not do "accepts_nested_attributes_for :recipients" in the award form. Can you help? Many thanks in advance.
class Recipient < ActiveRecord::Base
- has_many :awards
- has_many :announcers, :through => :awards
end
class Announcer < ActiveRecord::Base
- has_many :awards
- has_many :recipients, :through => :awards
end
class Award < ActiveRecord::Base
- belongs_to :announcer
- belongs_to :recipient
end
You're just about there. The main issue is that you're trying to create recipient objects in the form rather than just creating a relationship between the award and another object (user). You could do something like this:
class User < ActiveRecord::Base
has_many :recipients
has_many :awards, :through => :recipients
end
# this is your relationship between an award and a user
class Recipient < ActiveRecord::Base
belongs_to :user
belongs_to :award
end
class Award < ActiveRecord::Base
has_many :recipients
has_many :users, :through => :recipients
belongs_to :announcer
accepts_nested_attributes_for :recipients, :allow_destroy => true
end
class Announcer < ActiveRecord::Base
has_many :awards
has_many :recipients, :through => :awards
end
Then you would just do a nested form that would build the recipients_attributes array:
<%= form_for @award do |f| %>
<%= f.text_field :name %>
<div id="recipients">
<% @award.recipients.each do |recipient| %>
<%= render :partial => '/recipients/new', :locals => {:recipient => recipient, :f => f} %>
<% end %>
</div>
<%= link_to_function 'add recipient', "jQuery('#recipients').append(#{render(:partial => '/recipients/new').to_json})" %>
<% end %>
And, to keep it DRY just push the nested part into a partial:
# app/views/recipients/_new.html.erb
<% recipient ||= Recipient.new %>
<%= f.fields_for 'recipients_attributes[]', recipient do |rf| %>
<%= rf.select :user_id, User.all %>
<%= fr.check_box '_delete' %>
<%= fr.label '_delete', 'remove' %>
<% end %>
Obviously the User.all call isn't ideal so maybe make that an autocomplete.
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