CODEWITHSUNDEEP
ruby-on-rails
Raj Lalwani
Raj Lalwani

Reputation: 391

Rails : has_many_and_belongs_to on 3 models

I have 3 models in my Ruby on Rails say publisher, author and book. I want to create many to many relationship among them.

I have created a table called authors_books_publishers and added has_many_and_belongs_to in them.. for e.g.

Author
has_many_and_belongs_to :books
has_many_and_belongs_to :publishers

Book
has_many_and_belongs_to :authors
has_many_and_belongs_to : publishers

Publisher
has_many_and_belongs_to :authors
has_many_and_belongs_to :books

But it doesn't work when I try to add books in author

a = Author.new
b = Book.new 
a.books << b

It says (and rightly so) that system doesn't find a table called authors_books.

Please help

P.S. please treat the above models as e.g. They are not the real names in my app.

Thanks,

Upvotes: 0

Views: 1993

Answers (2)

Mikey Hogarth
Mikey Hogarth

Reputation: 4702

I did an article on active record associations a little while ago, here's the link;

http://mikeyhogarth.wordpress.com/2010/12/19/basic-activerecord-associations-overview/

I think it may involve the :through symbol. I am by no means a rails expert (trying to become one!) but hopefully that'll help.

Upvotes: 0

zed_0xff
zed_0xff

Reputation: 33257

you have to create 3 separate tables:

  1. authors_books
  2. books_publishers
  3. authors_publishers

and you probably the authors_publishers association is redundant b/c you could do same thing with author has_many :publishers, :thorough => :books

Upvotes: 1

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