From: Jason Foreman <threeve.org@...>
Date: 2005-05-04T21:35:37+09:00
Subject: Re: rails has_and_belongs_to_many problem

On 5/4/05, Igor Anic <ianic@4dva.hr> wrote:
> I have two classes Album and Korisnik (think about that as user),
> they are connected with album_korisnik table (I have pluralization
> turned off).
> 
> Her is the declaration:
> 
> class Album < ActiveRecord::Base
>         ...
>         has_and_belongs_to_many :prijatelji, :class_name => 'Korisnik'
>         ...
> 
> class Korisnik < ActiveRecord::Base
>         ...
>         has_and_belongs_to_many :albumi_prijatelja, :class_name => 'Album'
>         ...
> 
> I'm trying to add new korisnik to the album, and this is not working:
> prijatelji << k
> but this line is working ok
> k.albumi_prijatelja << self
> 
> In the first case i don't get any error in the log, and don't get any
> sql commands in transaction.
> 
> What I'm doing wrong?
> 
> Thanks,
> Igor
> 
> 


This should work:
a = Album.find(1) # find an album
k = Korisnik.find(1) # find a Korisnik
a.prijatelji << k # add the Korisnik to the album

Converserly:
a = Album.find(1) # find an album
k = Korisnik.find(1) # find a Korisnik
k.albumi_prijatelja << a # add the album to the Korisnik


Either way should add to the many-many association.  

I assume you are using "k.albumi_prijatelja << self" from inside a
method of the Album class?  which is why it might work.  If that is
the case, then your first example isn't working because I think it
would need to be "self.prijatelji << k" not just "prijatelji << k". 
If you are trying to do this within a controller method, then use the
examples I provided.

HTH,

Jason