在 Ruby on Rails 中从视图中删除逻辑

Question

I have an index view that iterates through a list of products with specific state_taxonomies. I was able to get the logic to work with a query request within the view, but I'm assuming <% Product.where(id: st.product_id).each do |tax| %> <% Product.where(id: st.product_id).each do |tax| %> logic should not display within a view?

1. Where should I put this logic?
2. How should I create this method? I've tried a few routes but failed.

Products index view user Bootstrap nav-pills:

<div>
  <% @state_taxonomies.each do |st| %>
    <div class="tab-pane" id="<%= st.id %>">
      <% Product.where(id: st.product_id).each do |tax| %>
        <%= link_to tax.title, tax %>
      <% end %>
    </div>
  <% end %>
</div>

Products Controller:

def index
  @products = Product.all.page params[:page]
  @state_taxonomies = StateTaxonomy.all 
end

Note: products has_many :state_taxonomies and state_taxonomy belongs_to :product.

Answer 1

You are doing a lot of queries, first in your controller Product.all (you don't seem to use the result) and StateTaxonomy.all . But the worse is in your view, you do a Product.where(id: st.product_id) for each @state_taxonomies .

You should research the n+1 problem and eager loading . Also, never do a query in a view, that goes in the controller.

All you need is to include the products when you query for StateTaxonomy in your controller :

@state_taxonomies = StateTaxonomy.all.includes(:product)

Then in your view :

<% @state_taxonomies.each do |st| %>
  <div class="tab-pane" id="<%= st.id %>">
    <% st.products.each do |tax| %>
      <%= link_to tax.title, tax %>
    <% end %>
  </div>
<% end %>

Edit : I just realized the view can't work this way. In your models, a state_taxonomy belongs to a product, so it can only have one product. I don't know if that is what you want or if it's an error.

You can either only show one product per state_taxonomy :

<% @state_taxonomies.each do |st| %>
  <div class="tab-pane" id="<%= st.id %>">
    <%= link_to st.product.title, st.product %>
  </div>
<% end %>

or change the relation between the two models, maybe you want has_and_belongs_to_many .

Answer 2

Your Products controller should be something like:

def index
  @state_taxonomies = StateTaxonomy.all
  @products = Hash.new
  @state_taxonomies.each |st| do 
    @products[st.id] == Product.where(id: st.product_id)
  end
end

This would store in @products all the required in your view and you could write only:

<% @state_taxonomies.each do |st| %>
  <div class="tab-pane" id="<%= st.id %>">
    <% @products[st.id].each do |tax| %>
      <%= link_to tax.title, tax %>
    <% end %>
  </div>
<% end %>