Question

So I have a nested resource with

resources :albums do 
  resources :elements
end

I can update, delete and view those elements.
What I can not really do is to create a new element.
So it is actually created in the database but not in the mapping table.
Models:

class Album:

has_many :elements, :through => :albums_elements      
has_many :albums_elements

class Element:

has_many :albums_elements
has_one  :album, :through => :albums_elements

class AlbumsElement:

belongs_to :album
belongs_to :element

In the element Controller I have:

def create
@element = Element.new(params[:element])
@album   = Album.find(params[:album_id])
respond_to do |format|
  if @element.save
    format.html { redirect_to album_elements_path(@album), :notice => 'Element was successfully created.' }
    format.json { render :json => @element, :status => :created, :location => @element }
  else
    format.html { render :action => "new" }
    format.json { render :json => @element.errors, :status => :unprocessable_entity }
  end
end
end

So as I said, when I press the create button in the form, the element is being created correctly in the table “elements”, but not inserted into “albums_elements”.
I saw a similar post here, where the author was told to fix his dependencies.
But I don’t see an error in mines?
How do I tell rails to insert into both tables?
elements AND albums_elements?

Answer 1

Would you please check by relating your @element and @album in elements_controller class? Like you already have

@element = Element.new(params[:element])
@album   = Album.find(params[:album_id])

Just add

@element.album = @album

Now @element.save should insert a entry in your relationship table also.

Let me know if it works. I’ve just answered after a glance to the problem.

Clarifications:

I will try to make a sample app for you. But before that i need to know some more.

• Seems the relationship between Album and Element is one-to-many, then why you are using has_many :through? It could be simply Album: has_many :products and Product: belongs_to :album.

• If you must use a relationship table, does it have any other attributes?

• Is it OK if I provide any solution of one-to-many?

I will try to provide you the best rails way to save these entries asap.
Thnx