Question

I am using polymorphic relation as i have 3 models like this:

class Food < ActiveRecord::Base
   has_many :images, as: :imageable, foreign_key: :imageable_uuid, dependent: :destroy
   accepts_nested_attributes_for :images, :allow_destroy => true
end
class MenuPhoto < ActiveRecord::Base
   has_one :image, as: :imageable, foreign_key: :imageable_uuid, dependent: :destroy
   accepts_nested_attributes_for :image
end
class Image < ActiveRecord::Base
   belongs_to :imageable, foreign_key: :imageable_uuid, :polymorphic => true
end

So in my “menu photo form”, I put it like this:

= simple_form_for @menu_photo do |f|
    = f.simple_fields_for :image_attributes do |d|
        = d.input :photo, as: :file 
        = f.submit

When i submit this form, it gives me like this:

{"menu_photo"=>{
    "image_attributes"=>
        {"photo"=>"user image upload"}
     }
}

It is correct. So in “food form” i do the same:

= simple_form_for @food do |f|
    = f.simple_fields_for :images_attributes do |d|
        = d.input :photo, as: :file 
        = f.submit

What i expect:

{"food"=>{
    "images_attributes"=>[
        {"photo"=>"user image upload one"}, 
        {"photo"=>"user image upload two"}
    ]}
}

What i got:

{"food"=>{
    "images_attributes"=>
        {"photo"=>"user image upload one"}
     }
}

That gives me an error. Any solution about this one?

Answer 1

If you defined has_many association:

has_many :images

has_many association will add some methods help you build and create object:

collection.build(attributes = {}, …)
collection.create(attributes = {})

collection here is images. You can read more here has_many

And when you define has_one association:

has_one :image

has_one association will add some methods help you build and create object:

build_association(attributes = {})
create_association(attributes = {})

create_association here is image. You can read more here has_one.

So, it will have the different way for you to create a new object associated with has_many and has_one.