Using checkboxes with parameters from a many-to-many link table

I have the following models

class Outbreak < ActiveRecord::Base
    has_many :risks
    has_many :factors, :through => :risks
end

class Risk < ActiveRecord::Base
    belongs_to :outbreak
    belongs_to :factor
end

class Factor < ActiveRecord::Base
    has_many :risks
    has_many :outbreaks, :through => :risks
end

Risk table
id : integer
outbreak_id : integer
factor_id : integer
details : text

In view/outbreak/edit

   <div id="factor_div">
    <% for factor in Factor.find(:all, :conditions => {:outbreak_type => @outbreak.outbreak_type}) %>
        <div>
        <%= check_box_tag "outbreak[factor_ids][]", factor.id , @outbreak.factors.include?(fact开发者_运维技巧or) %>
        <%= factor.name %>
        <%= text_field_tag "risk[details][]", @outbreak.risks.each{ |risk| if risk.factor_id == factor.id; risk} %>
        </div>

    <% end %>
   </div>

I'm trying to edit the Risk model details attribute (and populate the correct text_field from the @outbreak.risks array). Is it possible to do that using the approach of iterating through the Factors (which a table of mainly static variables - which have to occassionally altered by the end-users) and then checking whether or not each outbreak.risk has that factor_id or am i just going about this the wrong way?

(can't think - its friday afternoon and sunny out.... and theres a beer garden down the road ^^).

---

First, correct the association and update your results.

class Factor < ActiveRecord::Base
  has_many :risks
  has_many :outbreaks, :through => :risks
end