Printing join table

Rails
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” %>

<% for alloc in @allocations %> <% end %>
Company Product Quantity
<%=h alloc.company_id %> <%=h alloc.product_id %> <%=h alloc.quantity %>

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

On 23 January 2011 22:42, Craig L. [email protected] wrote:

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

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

On 24 January 2011 19:22, Craig L. [email protected] wrote:

@company = Company.find(params[:id])
end

I have also customized routes:
21:17:41) [POST]
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]

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 %>

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

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.