Ruby on Rails has_many：通过关联控制器

Question

these are my 3 models :

model for User:

class User < ActiveRecord::Base
has_many :patients, through: :treatments
has_many :treatments 
.
.
.

model for patient:

class Patient < ActiveRecord::Base
has_many :user, through: :treatments 
has_many :treatments, dependent: :destroy
.
.
.

model for treatment:

class Treatment < ActiveRecord::Base
belongs_to :patient
belongs_to :user
validates :patient_id, presence: true
default_scope -> { order(created_at: :desc) }
end

And this is my treatment table :

  class CreateTreatments < ActiveRecord::Migration
   def change
     create_table :treatments do |t|
      t.date :teartment_date
      t.text :remark
      t.float :fee
      t.references :patient, index: true, foreign_key: true

      t.timestamps null: false
    end
   add_index :treatments, [:patient_id, :created_at]
 end
end

now i want to define a controller to create a new treatment that belongs to a specific user's patient.

this is my controller :

  def new
    @treat = Treatment.new
  end

  def create    

   @userpatient = current_user.treatments.build(treat_params)

    if @userpatient.save
    flash[:success] = "new treatment added"
    redirect_to root_url
  else
    render 'new'
   end
end

but this is the error that i receive, while i want to create a new treatment :

ActiveRecord::UnknownAttributeError in TreatmentsController#create

 unknown attribute 'user_id' for Treatment.

and this is the current_user :

 def current_user
  if (user_id = session[:user_id])
   @current_user ||= User.find_by(id: user_id)
  elsif (user_id = cookies.signed[:user_id])
   user = User.find_by(id: user_id)
     if user && user.authenticated?(cookies[:remember_token])
     log_in user
     @current_user = user
   end
   end
   end

i'm new to rails, the basic idea is i want my user to have treatment that belongs to a specific patient.

Thanks to replies i've over come with this issue by adding a reference column . now i receive no, but it does not save any treatments. i mean the part :

if @treat.save
  flash[:success] = "new treatment added"
  redirect_to root_url
else
  render 'new'
end

it does not save and just render 'new' .

i have 2 questions :

1- how can i code my create controller ?

2- how to retrieve my treatments base on patient.what variable should i define in my patient 'show' method to have its treatments retrieved ?

Answer 1

When you say that User has_many :treatments and that Treatment belongs_to :user , both associations are expecting to find a user_id column in your treatments table. You might want to change your migration to include:

t.integer :user_id

and then drop your tables (if they have no data yet!) and rerun the migrations. Alternatively, you could create a new migration and simply run that:

    add_column :treatments, :user_id, :integer