Rails model relation MissingAttributeError

Question

I have some models in my application, and i'm trying to save data but i got an error:

ActiveModel::MissingAttributeError (can't write unknown attribute product_id): app/controllers/admin_controller.rb:27:in `create_product'

I have 3 models

Category model

class Category < ActiveRecord::Base
    has_many :features
    has_many :products
end

Migration:

class CreateCategories < ActiveRecord::Migration
   def change
     create_table :categories do |t|
     t.string :name, null: false
     t.boolean :active, null: false, default: false 
     t.timestamps null: false
   end
end

Feature Model

class Feature < ActiveRecord::Base
    has_and_belongs_to_many :categories
    has_and_belongs_to_many :products
 end

Migration

class CreateFeatures < ActiveRecord::Migration
   def change
      create_table :features do |t|
      t.belongs_to :category, index:true
      t.string :name, null: false
      t.timestamps null: false
   end
 end

Product model

class Product < ActiveRecord::Base
    belongs_to :category
    has_many :features 
end

Migration

class CreateProducts < ActiveRecord::Migration
   def change
      create_table :products do |t|
      t.belongs_to :category, index:true
      t.string :name, null: false
      t.text :rating, null: false
      t.timestamps null: false
    end
 end

I got this error when i try to save a product

ActiveModel::MissingAttributeError (can't write unknown attribute product_id): app/controllers/admin_controller.rb:27:in `create_product'

I cannot figure out what's happening

any ideas?

Thanks

Answer 1

If you look at your error, it clearly says

ActiveModel::MissingAttributeError (can't write unknown attribute product_id)

so you don't have a product_id field and looking at your associations and your features table migration, you forgot to add product_id field in your features table.

FIX:

To add product_id field in your features table you need to create a new migration and then migrate it to db:

rails g migration AddProductIdToFeatures product_id:integer
rake db:migrate