How to update relations using has_many through in Rails 4?

Question

There is the following code of controller:

def create
    @employee = business.beauty_salon_employees.build(employee_params)
    if @employee.save
                #
    else
        render 'new'
    end
end

def edit
    @employee = business.beauty_salon_employees.find(params[:id])
end

def update
    @employee = business.beauty_salon_employees.find(params[:id])
    if @employee.update(employee_params)
              #
    else
        render 'edit'
    end
end

protected
    def employee_params
    params.require(:beauty_salon_employee).permit(:name, :description, :phone, { beauty_salon_service_ids: [] })
end

And the following code of view:

- @business.beauty_salon_services.each do |s|
    .row
        = check_box_tag "beauty_salon_employee[beauty_salon_service_ids][]", s.id, @employee.beauty_salon_services.include?(s)
        = s.name  

Models code:

has_many :beauty_salon_employee_services, dependent: :destroy
has_many :beauty_salon_services,                    through: :beauty_salon_employee_services
accepts_nested_attributes_for :beauty_salon_services

And

has_many :beauty_salon_employee_services, dependent: :destroy
has_many :beauty_salon_employees,             through: :beauty_salon_employee_services

Problem is the following thing: when I create some BeautySalonEmployee with some checkboxes count checked (for example, 1) all is good. But when I try to update this record with no checkboxes checked I get no errors, but nothing is updated, ie when I open this record again I still see 1 checkbox checked. How can I fix it? What's wrong?

Answer 1

If check boxes aren't checked they aren't sent.

Just add a hidden field with the same name set to nil eg

= hidden_field_tag 'beauty_salon_employee[beauty_salon_service_ids][]', nil

This will be sent if none of the checkboxes are checked but if they are they will be sent instead