Rails - Mar 2008 - Associating a resource with multiple resources?

Hi,

I have these models in my ror application: author, article and book. I
want to associate author to article and book so:

book has many authors
article has many authors
author belongs to both of them

What''s the best practice for doing so? Should I have both book_id and
article_id in author table? Other solutions?

Thanks in advance,

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Houman,

I think you want a has_many :through relationship.  Here is an analogy:

http://wiki.rubyonrails.org/rails/pages/Beginner+Howto+on+has_many+:through

Arshak

Houman Dunnil wrote:
> Hi,
> 
> I have these models in my ror application: author, article and book. I
> want to associate author to article and book so:
> 
> book has many authors
> article has many authors
> author belongs to both of them
> 
> What''s the best practice for doing so? Should I have both book_id
and
> article_id in author table? Other solutions?
> 
> Thanks in advance,
-- 
Posted via http://www.ruby-forum.com/.

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If you have reasons to stick with the current model, then introduce a
fourth concept, call it ''Publishing''.  A
''publishing'' is something
that an author has written.  In this case, it associates an author to
a book or an article.  Now you can use two techniques --
has_many :through (as suggested by Arshak) and polymorphic
associations.

create_table :publishing do |t|
  t.reference :publishable, :polymorphic=>true
  t.reference :author
end

class Publishing < ARec::Base
  belongs_to :author
  belongs_to :publishable, :polymorphic=>true
  ...
end

class Author < ARec::Base
  has_many :publishings
  ...
end

class Book < ARec::Base
  has_many :publishings, :as=>:publishable
  has_many :authors, :through=>:publishing
  ...
end

class Article < ARec::Base
  has_many :publishings, :as=>:publishable
  has_many :authors, :through=>:publishing
  ...
end


The other possibility would be to use Single Table Inheritance,
putting the books and articles into a single table that uses a
discriminator column so that you can tell them apart.  You can still
use the has_many :through concept (to support 1 or more authors) but
you eliminate one table.

On Mar 23, 10:17 am, "Houman Dunnil"
<h.dun...-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>
wrote:
> Hi,
>
> I have these models in my ror application: author, article and book. I
> want to associate author to article and book so:
>
> book has many authors
> article has many authors
> author belongs to both of them
>
> What''s the best practice for doing so? Should I have both book_id
and
> article_id in author table? Other solutions?
>
> Thanks in advance,
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