I'm testing rails3 with Datamapper on a simple project.

I've 2 classes :
@@@class Societe include DataMapper::Resource

property :id, Serial property :nom, String property :adresse, Text

has n, :clients end

@@@class Client
  include DataMapper::Resource







  property :id,         Serial
  property :prenom,     String
  property :nom,        String
  property :telephone,  String
  property :courriel,   String
  property :adresse,    Text
  property :view_only,  Boolean







  belongs_to :societe
end

I created them using rails generate scaffold (except belongs/ has of
course).

I've then have in the folder "view" 5 erb templates per class, and
especially one (form) used by "new" and "edit" templates.
In order to select the society, I have added in client's form a
select:

@@@<%= form_for(@client) do |f| %> <%= f.error_messages %> ...

<%= f.label :societe %><br />
<%= f.select(:societe_id, @societes.map{|s| [s.nom, s.id]}) %>

<%= f.submit %>

In creation mode, everything is allright and the customer is created
with the link to its society
But when I edit, I have the following error:







@@@ Showing /home/.../app/views/clients/_form.html.erb where line #30
raised:







undefined method societe_id' for #<Client:0xa51833c>



Extracted source (around line #30):



27:   </div>
28:   <div class="field">
29:     <%= f.label :societe %><br />
30:     <%= f.select(:societe_id, @societes.map{|s| [s.nom, s.id]}) %>
31:   </div>
32:   <div class="actions">
33:     <%= f.submit %>

I've found an (very) ugly way to solve it:
in client class, I've added:
@@@class Client include DataMapper::Resource

property :id, Serial property :prenom, String property :nom, String property :telephone, String property :courriel, String property :adresse, Text property :view_only, Boolean

belongs_to :societe

def societe_id

societe.id

end end

This is in order to solve the issue. But then I wasn't able to update the record (the creation is still working well). So I've added some code in the controller:
@@@and in the update method of class_controller, I've added:
class ClientsController < ApplicationController  # PUT /clients/1
  # PUT /clients/1.xml
  def update

@client = Client.get(params[:id])

#########################

<New Stuff>

id = params[:client][:societe_id].to_i
params[:client].delete(:societe_id)

#########################

</New Stuff>

respond_to do |format|
  if @client.update(params[:client])

#########################

<New Stuff>

    if id != @client.societe.id
      @client.societe = nil
      new_societe = Societe.get(id)
      new_societe.clients << @client
      @client.save
    end

#########################

</New Stuff>

    format.html { redirect_to(@client, :notice => 'Client was

successfully updated.') }

    format.xml  { head :ok }
  else
    format.html { render :action => "edit" }
    format.xml  { render :xml => @client.errors, :status

=> :unprocessable_entity }

  end
end

  end



end

As I said it's ugly but it works. I think that dm-rails should handle that in a better way...