Question

class Product < ActiveRecord::Base
  has_many :models, :dependent => :destroy, :order => 'display, title'

class Model < ActiveRecord::Base
  belongs_to :product

class GsCollector < ActiveRecord::Base
  belongs_to :model

Why can’t I do the following in my form for GsCollector?:

  <p>
    Model:<br />
    <%= collection_select :gs_collector, :model_id, Product.where("title = 'Some Title'").models.all, :id, :title %>
  </p>

I get the error:

undefined method `models' for #<ActiveRecord::Relation:0x007fef0ac09350>

Shouldn’t the models method be provided by the relation? In the console, this works:

p = Product.find(4).models

But this doesn’t:

p = Product.where("title = 'some title'").models

Not sure what the difference is….

Here’s my schema:

  create_table "gs_collectors", :force => true do |t|
    t.integer  "project_id"
    t.integer  "model_id"
    t.integer  "quantity",   :default => 1
    t.string   "housing",    :default => "Base Unit"
    t.string   "hopper"
    t.string   "controller"
    t.boolean  "overbags",   :default => false
    t.datetime "created_at",                          :null => false
    t.datetime "updated_at",                          :null => false
  end

  create_table "models", :force => true do |t|
    t.string   "title"
    t.integer  "product_id"
    t.datetime "created_at"
    t.datetime "updated_at"
    t.integer  "display"
  end


  create_table "products", :force => true do |t|
    t.string   "title"
    t.datetime "created_at"
    t.datetime "updated_at"
  end

Answer 1

You are returning an array of objects, collectively called a ActiveRecord::Relation. This is due to your where search term. Maybe you want something like the following:

p = Product.find_by_title('some title').models

where returns a list of Products

find returns a single Product