Absolutely stuck trying to create nested association in rails form with has_many through

Question

I posted an earlier question about this and was advised to read lots of relevant info. I have read it and tried implementing about 30 different solutions. None of which have wor

Answer 1

Instead of calling:

@production = @miniature.productions.create

Try Rails' "build" method:

def new
  @miniature = Miniature.new(miniature_params)
  @miniature.productions.build
end

def create
  @miniature = Miniature.new(miniature_params)
  if @miniature.save
    redirect_to @miniature
  else
    render 'new'
  end
end

Using the build method uses ActiveRecord's Autosave Association functionality.

See http://api.rubyonrails.org/classes/ActiveRecord/AutosaveAssociation.html

You also need to update your params method, e.g.

def miniature_params
  params.require(:miniature).permit(:name, :release_date, :material, :scale, productions_attributes: [:manufacturer_id])
end

Also your fields_for should be plural (I think)...

<%= f.fields_for :productions do |production_fields| %>