Printing join table

rubyonrails-talk
1

Trying to print all instances of the company and product in a join table but unable to get the name : actually just trying to print every instance of a company in the join table

allocation.rb class Allocation < ActiveRecord::Base   belongs_to :company   belongs_to :product end

company.rb class Company < ActiveRecord::Base   has_many :products   has_many :allocations   has_many :products, :through => :allocations end

product.rb class Product < ActiveRecord::Base   belongs_to :company   has_many :allocations   has_many :companies, :through => :allocations end

Controller: class AllocationsController < ApplicationController

  def show     @company = Company.find(params[:id])     @allocations = @company.allocations.all   end

  def index     @allocations = Allocation.all   end

  def new     @allocations = Allocation.new   end

  def create     @allocations = Allocations.new(params[:allocations])     if @allocations.save       flash[:notice] = "Successfully created allocations."       redirect_to @allocations     else       render :action => 'new'     end   end

The index html page <% title "Allocations" %>

<table>   <tr>     <th>Company</th>     <th>Product</th>     <th>Quantity</th>   </tr>   <% for alloc in @allocations %>     <tr>       <td><%=h alloc.company_id %></td>       <td><%=h alloc.product_id %></td>       <td><%=h alloc.quantity %></td>     </tr>   <% end %> </table>

Is there a way to loop through each row, print the company name and the product in the join table?

I have tried this but get error: no method allocations defined <% title "Allocations" %>

<% @company.allocations.each_with_index do |allocation, index| %>   <%= allocation.product.name %>   ... <% end %>

2

you cannot have the same association twice, make the second one something like has_many :allocated_products, :through => allocations then for Allocation belongs_to :allocated_product, :class_name => 'Product' and the table needs an allocated_product_id column.

I think that is right, though I have never done this with :through association.

So you have company.products and company.allocated_products.

Colin

3

Colin

Thanks, this worked like a charm, brilliant! I can now do everything but create the allocations and formtastic is not sending the action create in the form to the controller

My Controller Allocations: class AllocationsController < ApplicationController

  def show     @company = Company.find(params[:id])     @allocations = @company.allocations.all   end

  def index     @allocations = Allocation.all   end

  def new     @company = Company.find(params[:id])     @allocations = Allocation.new   end

  def create     @allocations = Allocations.new(params[:allocations])     if @allocations.save       flash[:notice] = "Successfully created allocations."       redirect_to @allocations     else       render :action => 'new'     end   end

The view is: <% title "New Allocation" %><%= @company.name %> <% semantic_form_for @allocations do |f| %>   <% f.inputs do %>     <%= f.input :allocated_product %>     <%= f.input :quantity %>   <% end %>   <%= f.buttons %> <% end %>

I have also customized routes:   map.allocations 'companies/:id/allocations', :controller => "allocations", :action => "show"   map.clients 'clients', :controller => "allocations"   map.allocate 'companies/:id/allocations/new', :controller => "allocations", :action => "new"

The output on the console is strange as I don't get the "create" action called just "show" and see in show action nothing has been added.

Processing AllocationsController#show (for 127.0.0.1 at 2011-01-24 21:17:41) [POST]   Parameters: {"commit"=>"Create Allocation", "action"=>"show", "authenticity_token"=>"zpScMwZRZix3Ube1aTbQJplv+ZI0KXpskD7xB4yOo3g=", "id"=>"1", "allocation"=>{"quantity"=>"90", "allocated_product_id"=>"2"}, "controller"=>"allocations"}   User Columns (1.1ms) SHOW FIELDS FROM `users`   Company Columns (0.7ms) SHOW FIELDS FROM `companies`   Company Load (0.1ms) SELECT * FROM `companies` WHERE (`companies`.`id` = 1)   Allocation Load (0.1ms) SELECT * FROM `allocations` WHERE (`allocations`.company_id = 1) Rendering template within layouts/welcome Rendering allocations/show   Allocation Columns (0.6ms) SHOW FIELDS FROM `allocations`   CACHE (0.0ms) SELECT * FROM `companies` WHERE (`companies`.`id` = 1)   Product Columns (0.7ms) SHOW FIELDS FROM `products`   Product Load (0.1ms) SELECT * FROM `products` WHERE (`products`.`id` = 1) Completed in 123ms (View: 21, DB: 4) | 200 OK [http://0.0.0.0/companies/1/allocations\]

4

Sorry, I am not sure what question you are asking. Please explain simply what you are doing and what is or is not happening. Try not to provide more code than necessary. It cannot be necessary to show us four controller actions for example.

Colin

5

Sorry: will try again

I have now managed to do the modeling using the suggestions above

class Allocation < ActiveRecord::Base   belongs_to :company   belongs_to :allocated_product, :class_name => 'Product' end

class Company < ActiveRecord::Base   has_many :products   has_many :allocations   has_many :allocated_products, :through => :allocations

class Product < ActiveRecord::Base   belongs_to :company   has_many :allocations   has_many :companies, :through => :allocations

I am trying to create a new company and at the same time allocate a product as allocated product with quantity to allocate. The product table has a company_id as it belongs to a company (supplier), but here the allocated products needs to be allocated to the companies to allow them to be clients and hence the join table: allocations

class CompaniesController < ApplicationController

  def new     @allocations = Allocation.all     @company = Company.new   end

  def create     @company = Company.new(params[:company])     params[:allocated_products].each_value do |k|       @company.allocated_products.build(k)     end     if @company.save       flash[:notice] = "Successfully created company."       redirect_to @company     else       render :action => 'new'     end   end

The view: <% title "New Company" %> <% semantic_form_for @company do |f| %>   <% f.inputs do %>     <%= f.input :name %>     <%= f.input :contacts, :as => :check_boxes, :label => "Contacts representing the company" %>     <%= f.input :allocated_products %>   <% end %>   <%= f.buttons %> <% end %>

<p><%= link_to "Back to List", companies_path %></p>

The form is properly displayed but when saving errors with: NoMethodError in CompaniesController#create undefined method `each_value' for nil:NilClass

I assume this means it cannot identify the array that is coming: should I be able to see the id of params in the html source? If I did this manually and not using Formtastic what would it look like: I have looked at fields_for but then cannot put it into a collection select method.