has_many relationship with images in the def create - ruby-on-rails-3

Question

I am trying to create many images for a single product.
Since the number of images per product is as many as the user wants to enter I have created 2 separate models, product and product_image.
Product has many product_images
and product_images belongs_to product
I'm almost certain that this section of code is the problem (this is the product_image controller)
def create
#product_image = ProductImage.new(params[:product_image])
#product = #product_image.product
if #product_image.save
#product_image.product_id = #product.id
#product_image.save
redirect_to #product_image, notice: 'Product image was successfully created.'
else
render :template => "products/edit"
end
end
At the moment the code allows me to upload an image via paperclip but totally disregards the product_id and just puts the product_image_id in that field instead.
I checked the db through the cmd line to see this.
So how do I get an image to be created with an ID of a particular product? I've searched this site but the questions that exist do seem to offer the solution that I require.
Thanks for any help you can offer.
Here are the migrations that I used for the models relating to products and product_images
I apologize for the mess, I was very indecisive in my initial development which caused lost of little changes to be made as I gained more knowledge about the whole rails system
products
class CreateProducts < ActiveRecord::Migration
def change
create_table :products do |t|
t.string :name
t.text :description
t.string :image_url
t.decimal :price, precision: 8, scale: 2
t.timestamps
end
end
end
and, products
class AddColumnsToProducts < ActiveRecord::Migration
def change
drop_table :products
create_table :products do |t|
t.string :product_title
t.text :product_desc
t.string :product_image_url
t.decimal :price, precision: 8, scale: 2
t.timestamps
end
end
end
and, products
class AddColumnToProducts < ActiveRecord::Migration
def change
add_column :products, :department, :string
end
end
and, products
class AddMoreColumnsToProducts < ActiveRecord::Migration
def change
add_column :products, :display_on_home_page, :boolean, default: false
add_column :products, :is_highight_product, :boolean, default: false
end
end
and, products
class RenameIsHighightProductInProducts < ActiveRecord::Migration
def up
rename_column :products, :is_highight_product, :is_highlight_product
end
def down
end
end
and, products
class RenameProductImageUrlInProducts < ActiveRecord::Migration
def up
rename_column :products, :product_image_url, :image_url
end
def down
end
end
and product images table created
class CreateProductImages < ActiveRecord::Migration
def change
create_table :product_images do |t|
t.integer :product_id
t.string :title
t.text :description
t.string :image_file_name
t.string :image_content_type
t.integer :image_file_size
t.datetime :image_updated_at
t.timestamps
end
end
end
and, products
class AlterTableProducts < ActiveRecord::Migration
def up
end
remove_column :products, :image_url
add_column :products, :product_image_id, :integer
def down
end
end
and, product_images
class AddColumnToProductImages < ActiveRecord::Migration
def change
add_column :product_images, :image_path, :string
end
end
and, product_images
class RenameColumnImagePathInProductImages < ActiveRecord::Migration
def up
rename_column :product_images, :image_path, :image_url
end
def down
end
end
and, product_images
class AddProductTitleColumnToProductImages < ActiveRecord::Migration
def change
add_column :product_images, :product_title, :string
end
end
and finally, products
class DropPriceFromProductsAndAddPriceToProducts < ActiveRecord::Migration
def up
end
remove_column :products, :price
add_column :products, :price, :decimal, :precision => 8, :scale => 2
def down
end
end

Answer 1

I am not sure what is going wrong because there is a little too less info in your question. But let me show quickly, how this should be set up (simplified).
new rails app:
rails new stack_product
creating the models
rails g model product
rails g model image
You get all this (you have to add the attr_accessible attributes by hand here)
app/models/product.rb
class Product < ActiveRecord::Base
attr_accessible :title, :description
has_many :images
end
app/models/image.rb
class Image < ActiveRecord::Base
attr_accessible :name, :path, :product_id
belongs_to :product, foreign_key: "product_id"
end
db/migrations/20131011195035_create_products.rb
class CreateProducts < ActiveRecord::Migration
def change
create_table :products do |t|
t.primary_key :id
t.string :title
t.string :description
t.string :image_url
t.timestamps
end
end
end
20131011195421_create_images.rb
class CreateImages < ActiveRecord::Migration
def change
create_table :images do |t|
t.primary_key :id
t.integer :product_id
t.string :name
t.string :path
t.timestamps
end
end
end
use rails console in the terminal.
rails console
the fire:
Product.create({title: 'Ford Mustang', description: 'The one and only Shelby'})
...
Image.create({product_id: 1, name: 'Image Mustang', path: '/images/mustang.png'})
Image.create({product_id: 1, name: 'Image Mustang from behind', path: '/images/mustang2.png'})
then you can query the objects
p = Product.find(1)
Product Load (0.2ms) SELECT "products".* FROM "products" WHERE "products"."id" = ? LIMIT 1 [["id", 1]]
=> #<Product id: 1, title: "Ford Mustang", description: "The one and only Shelby", image_url: nil, created_at: "2013-10-11 20:14:06", updated_at: "2013-10-11 20:14:06">
Image.where("product_id=?", p.id)
Image Load (0.3ms) SELECT "images".* FROM "images" WHERE (product_id=1)
=> [#<Image id: 1, product_id: 1, name: "Image Mustang", path: "/images/mustang.png", created_at: "2013-10-11 20:14:09", updated_at: "2013-10-11 20:14:09">, #<Image id: 2, product_id: 1, name: "Image Mustang from behind", path: "/images/mustang2.png", created_at: "2013-10-11 20:14:26", updated_at: "2013-10-11 20:14:26">]
So this works fine. If you would create forms for this, you would have one for the products and another one for the images. The images form would have a dropdown with all the products (productname and value with id). The dropdown for the products would be named product_id and then the product's id would be saved in the image table as product_id.
You should maybe scaffold all this to see how it is be done by Rails.