Rails - Jan 2008 - has_many :through with self-referencial AND polymorphism

Hello, despite many readings I still don''t understand how to solve my
problem.

I have Publication, Picture, File classes
A Publication can be related (a one way relation, like a www link) with
another Publication, Picture or File

I tried this :

Publication :
has_many :related_elements, :dependent => :destroy, :foreign_key =>
:publication_id
has_many :related, :through => :related_elements, :as => :linked,
:source => :publication

RelatedElement :
belongs_to :publication

And migrate as
create_table :related_elements do |t|
      t.integer     :linked_id
      t.string      :linked_type
      t.integer     :publication_id
end

When I do
a_publication.related[0] = another_publication
a_publication.save!

I would expect the related_elements table beeing updated with
publication_id = the id of a_publication
linked_id = the id of another_publication
linked_type = the class name ''Publication''

But nothing happen... And I must confess that I''m pretty sure my
has_many are totally wrong

All this stuff is really too complex for me, so your help will be
greatly appreciated !! Thanks
-- 
Posted via http://www.ruby-forum.com/.

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here you have an example

http://pastie.org/140772

I hope it helps.

2008/1/18, Tom Salporia
<rails-mailing-list-ARtvInVfO7ksV2N9l4h3zg@public.gmane.org>:
>
> Hello, despite many readings I still don''t understand how to solve
my
> problem.
>
> I have Publication, Picture, File classes
> A Publication can be related (a one way relation, like a www link) with
> another Publication, Picture or File
>
> I tried this :
>
> Publication :
> has_many :related_elements, :dependent => :destroy, :foreign_key =>
> :publication_id
> has_many :related, :through => :related_elements, :as => :linked,
> :source => :publication
>
> RelatedElement :
> belongs_to :publication
>
> And migrate as
> create_table :related_elements do |t|
>       t.integer     :linked_id
>       t.string      :linked_type
>       t.integer     :publication_id
> end
>
> When I do
> a_publication.related[0] = another_publication
> a_publication.save!
>
> I would expect the related_elements table beeing updated with
> publication_id = the id of a_publication
> linked_id = the id of another_publication
> linked_type = the class name ''Publication''
>
> But nothing happen... And I must confess that I''m pretty sure my
> has_many are totally wrong
>
> All this stuff is really too complex for me, so your help will be
> greatly appreciated !! Thanks
> --
> Posted via http://www.ruby-forum.com/.
>
> >
>

-- 
-------------------------------------
Pedro Del Gallego

Email              :   pedro.delgallego-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org

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Pedro Del gallego wrote:

Thanks Pedro, this is a first step in the right direction.
Now I would like to add support for polymorphism, I mean that the item 
related could be of different class (this -> related_to -> book, this
->
related_to -> image, and so on)

It seems that it''s not a simple case 
(http://blog.hasmanythrough.com/2006/4/3/polymorphic-through)

Does it changed with Rails 2.0 ?

I tried the solution provided on the hasmanythrough blog but without 
success.

Should I go to the has_many_polymorphs plugin ?? 
(http://blog.evanweaver.com/files/doc/fauna/has_many_polymorphs/files/README.html)

I don''t like the idea of overusing plugins when I don''t know
how to
handle a special situation... It''s kind of black box in that case

Thanks
-- 
Posted via http://www.ruby-forum.com/.

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