The error "Couldn't find Item with ID=123 for Payment with ID=" occurs when adding existing Item models to a new Payment model. This is in a has_many relationship and using accepts_nested_attributes_for.
class Payment < ActiveRecord::Base
has_many :items
accepts_nested_attributes_for :items
...
class Item < ActiveRecord::Base
belongs_to :payment
...
The payment and item models are hypothetical but the problem is real. I need to associate the Items with the Payment (as I do in the new action) before saving the Payment (done in the create action). The user needs to modify attributes on the Items as they create the Payment (adding a billing code would be an example).
Specifically, the error occurs in the controller's create action:
# payments_controller.rb
def new
@payment = Payment.new
@payment.items = Item.available # where(payment_id: nil)
end
def create
@payment = Payment.new payment_params # <-- error happens here
...
end
def payment_params
params.require(:payment).permit( ..., [items_attributes: [:id, :billcode]])
end
lib/active_record/nested_attributes.rb:543:in 'raise_nested_attributes_record_not_found!'
is immediately prior to it in the callstack. It is curious that ActiveRecord is including payment_id as part of the search criteria.
For the sake of being complete, the form looks something like this...
form_for @payment do |f|
# payment fields ...
fields_for :items do |i|
# item fields
and it renders the Items correctly on the new action. The params passed through the form look like this:
{ "utf8"=>"✓",
"authenticity_token"=>"...",
"payment"=>{
"items_attributes"=>{
"0"=>{"billcode"=>"123", "id"=>"192"}
},
}
}
If there is a better way to approach this that doesn't use accepts_nested_attributes_for
I'm open to suggestions.
I got this to work by just adding an item_ids
collection to the params (in addition to the items_attributes
). You should just be able to massage your parameters in the controller to look like this
{ "utf8"=>"✓",
"authenticity_token"=>"...",
"payment"=>{
"item_ids"=>[192]
"items_attributes"=>{
"0"=>{"billcode"=>"123", "id"=>"192"}
},
}
}
UPDATE 1: For some reason this only works if item_ids
is before items_attributes
in the hash. Have not reviewed Rails docs yet to figure out why.
This confused me...
"Adding existing records to a new record..."
So you have Item 1, 2, 3
, and wish to associate them to a new Product
object?
--
Join Model
The way to do this will be to use a join model
(habtm
) rather than sending the data through accepts_nested_attributes_for
The bottom line is every time you create a new Product
object, its associated Item
objects can only be associated to that product:
#items table
id | product_id | information | about | item | created_at | updated_at
So if you're looking to use existing
Item
objects, how can you define multiple associations for them? The fact is you can't - you'll have to create an intermediary table / model, often cited as a join model
:
#app/models/product.rb
Class Product < ActiveRecord::Base
has_and_belongs_to_many :items
end
#app/models/item.rb
Class Item < ActiveRecord::Base
has_and_belongs_to_many :products
end
#items_products (table)
item_id | product_id
--
HABTM
If you use a HABTM setup (as I have demonstrated above), it will allow you to add / delete from the collection
your various objects have, as well as a sneaky trick where you can just add Items
to a product using item_ids
:
#app/controllers/products_controller.rb
Class ProductsController < ApplicationController
def create
@product = Product.new(product_params)
@product.save
end
private
def product_params
params.require(:product).permit(item_ids: [])
end
end
If you then pass the param item_ids[]
to your create_method
, it will populate the collection
for you.
If you want to add specific items to a product
, or remove them, you may wish to do this:
#app/controllers/products_controller.rb
Class ProductsController < ApplicationController
def add
@product = Product.find params[:id]
@item = Item.find params[:item_id]
@product.items << @item
@product.items.delete params[:item_id]
end
end
If you love us? You can donate to us via Paypal or buy me a coffee so we can maintain and grow! Thank you!
Donate Us With