Question

I need to create a new entity B whenever I create an entity A. To do this I tried adding a call to B.create inside the A.create method in a_controller. This however gives an error:

Missing template a/create

So my question is: how do I create an entity B from the A.create controller?

Answer 1

something like this?

def create
  @A = A.new(params[:a])
  @B = B.new(params[:b])

  respond_to do |format|
    if @A.save && @B.save
      format.html { redirect_to @A, :notice => 'A was successfully created.' }        
    else
      # render new with validation errors
      format.html { render :action => "new" }        
    end
  end
end

but if your objects are ‘related’, i.e. has_many or belongs_to then you might want something like

# project has_many tasks
def create
  @project = Project.new(params[:project])
  @project.tasks.new(params[:task])
  if @project.save # this should save both objects and in the same transaction
    ....
end

and third option is to use accepts_nested_attributes_for – read more here: http://currentricity.wordpress.com/2011/09/04/the-definitive-guide-to-accepts_nested_attributes_for-a-model-in-rails-3/