How can get array values using has_and_belongs_to_many? - ruby-on-rails

Question

Can't save params selected on select box.
Table users:
1id| |name|
1 CR7
2 Messi
Table ejecutives:
1id| |name|
1 Mourinho
2 Guardiola
Table user_ejecutives:
|id| |user_id| |ejecutive_id|
1 1 1
2 2 2
Controller users_controller.rb:
def new
#obj_user = User.new
end
def create
#user = User.new user_params
#user.save
end
def show
#user = User.find(params[:id])
end
private
def user_params
params.require(:user).permit(:name, user_ejecutive_ids: [])
end
Models:
#User.rb
has_many :ejecutives, :through => :user_ejecutives
has_many :user_ejecutives
has_and_belongs_to_many :user_ejecutives, class_name: "User", join_table: "user_ejecutives"#, foreign_key: :user_id, association_foreign_key: :ejecutive_id
#Ejecutive.rb
has_many :user_ejecutives
has_many :users, :through => :user_ejecutives
#UserEjecutive.rb
belongs_to :user
belongs_to :ejecutive
View new.html.erb:
<%= form_for #user do |f| %>
<%= form.text_field :name %>
<%= f.collection_select :user_ejecutive_ids, Ejecutive.all, :id, :name, multiple: true %>
<% end %>
View show.html.erb
<% #user.ejecutives.each do |ejecutive| %>
<%= ejecutive.name %></label>
<% end %>
I'm not getting results on the view show and it show on logs:
SystemStackError (stack level too deep):

Answer 1

If you're just trying to populate the join table (user_ejecutives), you'll want to populate the singular_colletion_ids method:
#app/controllers/users_controller.rb
class UsersController < ApplicationController
def new
#user = User.new
end
def create
#user = User.new user_params
#user.save
end
private
def user_params
params.require(:user).permit(:name, user_ejecutive_ids: [])
end
end
#app/views/users/new.html.erb
<%= form_for #user do |f| %>
<%= f.collection_select :user_ejecutive_ids, User.all, :id, :name, multiple: true %>
<%= f.submit %>
<% end %>
This will assign new user_ejecutives for each new #user you create.
PS User.all is valid in this instance as you're dealing with a new (uncreated) #user record, hence it won't appear in the db.
If you wanted to create new user_ejecutives with each new #user, you'll want to use accepts_nested_attributes_for, which I can explain if required.
Update
So your error is as follows:
Unpermitted parameter: user_ejecutive_ids
... you also have another error...
NoMethodError (undefined method `each' for nil:NilClass):
This is exactly why I don't like your code. Because it doesn't fit to convention, you've go to evaluate whether the params are present etc.
You'll need to use the controller code I posted - it will populate the other table for you, and fix this NilClass error.
--
Join Table
Your user_ejecutives table is a join table.
Your User model should have the following:
#app/models/user.rb
class User < ActiveRecord::Base
has_and_belongs_to_many :user_ejecutives, class_name: "User", join_table: "user_ejecutives", foreign_key: :user_id, association_foreign_key: :ejecutive_id
end
You'll have to remove the id column from your user_ejecutives table (as per the definition here). The importance of this is that it gives you the ability to populate the singular_collection_ids method (in your case user_ejective_ids), as per my recommended code.

Answer 2

Try the following code.
params.require(:user).permit(:name, :user_ejecutives => [])
Hey, I think you have "ejecutive_id" column declared as integer but when loop through "user_ejecutives" you are getting each value as string, May be this is causing the issue, Kindly update your create action to below.
def create
obj_user = User.new(user_params)
if obj_user.save
params[:user_ejecutives].each do |ejecutive|
user_ejecutive = UserEjecutive.create(user_id: obj_user.id, ejecutive_id: ejecutive.to_i)
user_ejecutive.save
end
end
end