Rails - Nov 2006 - How do I have two habtm between same two tables

I need two many-to-many models between the same two tables.

The two tables are documents and authors.  I model documents and  
authors using habtm.  I also need to model the records of the authors  
table as corresponding_authors having a many-to-many relationship  
with documents.  Do use habtm for the second model?  Or another  
technique?

Jose

.......................................................
Jose Hales-Garcia
UCLA Department of Statistics
jose-oNoWckAxTcaFhjwBz98joA@public.gmane.org






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Hello Jose,
  I''m not sure I quite understand the question, but I''ll
attempt to help.
The problem is, you have two models, Authors and Documents, and you have two
many-to-many between them.  Suppose one of these relationships is authorship
(by that, I mean a particular author contributed to the writing of a
particular document).  Suppose the other relationship is ..., I don''t
know,
mentions (by that I mean, a particular author is mentioned in a document).
If that is the situation, I would create two models in addition to the
Author and Document models: Authorship and Mention.

class Authorship < ActiveRecord::Base
  belongs_to :author  # this author helped write ...
  belongs_to :document # this document
end

class Mention < ActiveRecord::Base
  belongs_to :authors # this author is mentioned in ...
  belongs_to :documents # this document
end

class Author < ActiveRecord::Base
  has_many :authorships
  has_many :authored_documents,
    :through => :authorships,
    :class_name => ''Document'',
    :foreign_key => ''document_id''

  has_many :mentions
  has_many :mentioned_documents,
    :through => :mentions,
    :class_mane => ''Document'',
    :foreign_key => ''document_id''
end

class Document < ActiveRecord::Base
  has_many :authorships
  has_many :authors,
    :through => :authorships,
    :class_name => ''Author'',
    :foreign_key => ''author_id''

  has_many :mentions
  has_many :mentioned_authors,
    :through => :mentions,
    :class_mane => ''Author'',
    :foreign_key => ''author_id''
end

The names of my methods and variables are a little odd, but hopefully the
concept is clear.  You might want to watch DHH''s railsconf keynot on
CRUD
[1].  If I did not answer the right question (likely), please let me know,
and I''ll try again.




[1]
http://blog.scribestudio.com/articles/2006/07/09/david-heinemeier-hansson-railsconf-2006-keynote-address

On 11/30/06, Jose Hales-Garcia
<jose-oNoWckAxTcaFhjwBz98joA@public.gmane.org>
wrote:
>
>
> I need two many-to-many models between the same two tables.
> The two tables are documents and authors.  I model documents and authors
> using habtm.  I also need to model the records of the authors table as
> corresponding_authors having a many-to-many relationship with documents. 
Do
> use habtm for the second model?  Or another technique?
>
> Jose
>
> .......................................................
> Jose Hales-Garcia
> UCLA Department of Statistics
> jose-oNoWckAxTcaFhjwBz98joA@public.gmane.org
>
>
>
>
>
> >
>

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