Rails 5 many to many index - ruby-on-rails

Question

I am having a problem in the eyes when presenting the data.
I have 3 user models, sponsors and pets Result that sponsors in a table join between users and pets that are nan, my problem is in the hour to show all the sponsors of the mascot in sight and achievement but in a wrong way to La time to msotrar the data. I hope you can tell me how to fix it. Thank you.
Index.html.erb
<h1>Sponsors#index</h1>
<table class="table table-bordered table-hover table-striped" id="histories">
<thead>
<tr>
<th>Mascota</th>
<th>Padrinos</th>
<th>Apadrinar</th>
</tr>
</thead>
<tbody>
<% #pets.each do |pet| %>
<tr>
<td><%= pet.name %></td>
<td>
<% #users.each do |user| %>
<% #sponsors.each do |sponsor| %>
<% if user.id == sponsor.user_id and pet.id == sponsor.pet_id %>
<%= user.email%>
<% else %>
<p>No Tengo Padinos =-( </p>
<% end %>
<% end %>
<% end %>
</td>
<td><button>Apadrinar</button></td>
</tr>
<% end %>
</tbody>
</table>
My controller has the three models that I am sending to view.
def index
#sponsors = Sponsor.all
#users = User.all
#pets = Pet.all
end
pet.rb
class Pet < ApplicationRecord
has_many :adoptions
belongs_to :race, required: false
has_many :users, through: :sponsors
end
user.rb
class User < ApplicationRecord
has_many :pets, through: :sponsors
end
sponsor.rb
class Sponsor < ApplicationRecord
belongs_to :user
belongs_to :pet
end
The output that now shows me the attachment in the image.enter image description here
I also wonder if there is a better way to make the query, to show the respective data.
Another thing is how would I do to no longer be able to sponsor pets that I have already given a sponsor?

Answer 1

You are using a through table to join users and pets, but your associations aren't setup properly. For a through model, you have to have_many of the through table along with a has_many: :through association. Your associations should look like this:
class Pet < ApplicationRecord
has_many :adoptions
belongs_to :race, required: false
**has_many :sponsors**
has_many :users, through: :sponsors
end
class User < ApplicationRecord
**has_many :sponsors**
has_many :pets, through: :sponsors
end

Answer 2

Afther working and following diferent recomendations here is my solution.
<% #pets.each do |pet| %>
<tr>
<td> <%= pet.name %></td>
<td>
<% if pet.sponsors.any? %>
<% pet.sponsors.each do |sponsor| %>
| <%= sponsor.user_email %> |
<% end %>
<% else %>
<p>No Tengo Padinos =-( </p>
<% end %>
</td>
<td>
<%= link_to "Apadrinar", {:controller => "sponsors", :action => "new", :mascot => pet.id }%>
</td>
</tr>
<% end %>
I changed also my models.
sponsor.rb
class Sponsor < ApplicationRecord
belongs_to :user
belongs_to :pet
has_many :gifts
delegate :email, to: :user, prefix: true, allow_nil: true
end
user.rb
class User < ApplicationRecord
has_many :sponsors
has_many :pets, through: :sponsors
end
pet.rb
class Pet < ApplicationRecord
has_many :sponsors
has_many :users, through: :sponsors
end
And finally mi index on Controller.
sponsors_controller.rb
def index
# #sponsors = Sponsor.all
# #users = User.all
# #pets = Pet.all
# #pets_no_sponsors = Pet.where.not(id: Sponsor.select("pet_id")).select("id")
#pets = Pet.includes(:sponsors)
end
By making a delegation now I only make a query which sends everything necessary to my index.