Rails - Polymorphic has_many：通过关联 - '无法在模型中找到源关联'错误

Question

I have been scouring the internet and have tried lots of different ways to fix this problem but I am really stuck. I'm fairly new to rails so I might have missed something obvious!

The problem I have is with polymorphic associations involving 4 models:

(1) User, (2) Approver, (3) Recipient, (4) Note

A User has many Approvers and has many Recipients. A user can also leave notes for both approvers and recipients. A note has a polymorphic association to approvers and recipients as :notable. My models look as follows:

Note.rb

class Note < ApplicationRecord
  belongs_to :user
  belongs_to :notable, polymorphic: true
end

Approver.rb

 class Approver < ApplicationRecord
   belongs_to :user
   has_many :notes, as: :notable
 end

Recipient.rb

class Recipient < ApplicationRecord
  belongs_to :user
  has_many :notes, as: :notable
end

User.rb

class User < ApplicationRecord
  has_many :approvers, dependent: :destroy
  has_many :recipients, dependent: :destroy

  # This is the bit that I think is the problem:
  has_many :notes, through: :approvers, source: :notable, source_type: "Note"
  has_many :notes, through: :recipients, source: :notable, source_type: "Note"
end

Basically I want to be able to do

User.find(1).notes (...etc)

and show all of the notes for that user from both approvers and recipients.

In the approver view, for instance, I can do @approver.notes.each and iterate through them fine.

The error message that I am getting is: "Could not find the source association(s) :note_owner in model Recipient. Try 'has_many :notes, :through => :recipients, :source => '. Is it one of user or notes?"

Can anyone see what I am missing!?

Answer 1

In order to get the user's notes the way you mentioned, you will have to to add a foreign key for that user. For example,

When an adviser adds a note, that note saves the adviser id and the note itself but there is currently no reference to the user that receives the note from the adviser. If you add to the note schema a user id references, you can pull out all the notes of a particular user.

EX.

Note schema:

user_id: references (the user the note is for)
writer_id: references (the user that writes the note)
note: text (your actual note)

You can than build that note like this:

current_user.create_note(params[:user], params[:note])   # pass the user as a reference

def create_note(user, note)
  Note.create(user_id: user.id,
              write_id: current_user.id
              note: note)
end

Once you create a user like this, you can call on any user: user.notes and it should return an array of notes for that user.