ruby on rails 4 - How do you add a second column of 'children' without duplicating the 'parent' column entry in Active Admin? -

this table, raw table correct output, result looking for, how translate block of code whatever active admin /app/admin/postal_code.rb index view requires output table correctly.

currently block rendered in partial, /app/views/admin/postalcode/_showtable.html.erb

<h1>postal code per region</h1> <table> <tr>     <th>region</th>     <th>postal code</th> </tr> <% @region.each |region| %> <tr>     <td><%= region.name %></td>     <td>         <table>             <% list = @postalcode.where("region_id=#{region.id}") %>             <% list.each |l| %>             <tr>                 <td width="5%">                     <%= l.postalcode %>                 </td>             </tr>            <% end %>            <% end %>           </td>         </table> </table> 

but code, active admin index view, in /app/admin/postal_code.rb giving multiple parent column entries, 1 each second column child entry.

activeadmin.register postalcode menu parent: "region settings" permit_params :postalcode, :region_id   index  column :id  column :region  column "postal code" |region|    region.postalcode  end end 

in app/models/postal_code.rb

class postalcode < activerecord::base belongs_to :region validates :region_id, presence: true validates :postalcode, presence: true # scope :region, -> (name) { } # postalcode.all.group_by(&:region_id) end 

and in app/models/region.rb

class region < activerecord::base validates :name, presence: true has_many :postalcodes # has_many :produces, :through => :produceregionmonths end 

here's how can create individual tables header of region name , corresponding postalcodes inside

# app/admin/postal_code.rb  index   region.all.each |region|     table_for(postalcode.where(region_id: region.id), class: 'index_table')       column region.name |postal_code|         postal_code.postalcode       end       actions     end   end end