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Vincent Lin

2012-Jul-30 06:06 UTC

How do I create a form for "has_and_belongs_to_many" association?

git://github.com/vincentopensourcetaiwan/vocabulary.git
This is my source codes.

I got two models, Book and Word. 

class Book < ActiveRecord::Base 
  has_and_belongs_to_many :words 
end 

class Word < ActiveRecord::Base 
   has_and_belongs_to_many :books 
end

I got a Join Tables for has_and_belongs_to_many Associations 

class CreateBooksWords < ActiveRecord::Migration 
  def self.up 
    create_table :books_words, :id => false do |t| 
      t.integer :book_id 
      t.integer :word_id 

      t.timestamps 
    end 
  end 

  def self.down 
    drop_table :books_words 
  end 
end

Now I want to create a form, and user can insert words into a book. 
How do I do that?

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Vincent Lin

2012-Jul-30 06:16 UTC

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How do I create a form for "has_and_belongs_to_many" association?

git://github.com/vincentopensourcetaiwan/vocabulary.git
This is my source codes.

I got two models, Book and Word. 

class Book < ActiveRecord::Base
  attr_accessible :description, :name
  has_and_belongs_to_many :words
end

class Word < ActiveRecord::Base
  attr_accessible :name
end

I got a Join Tables for has_and_belongs_to_many Associations 

class CreateBooksWords < ActiveRecord::Migration
  def change
    create_table :books_words, :id => false do |t|
      t.references :book
      t.references :word

      t.timestamps
    end
    add_index :books_words, :book_id
    add_index :books_words, :word_id
  end
end

How do I create a form for users to insert words into a book?

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masta Blasta

2012-Jul-31 19:05 UTC

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Re: How do I create a form for "has_and_belongs_to_many" association?

Vincent Lin wrote in post #1070656:> git://github.com/vincentopensourcetaiwan/vocabulary.git
> This is my source codes.
>
> I got two models, Book and Word.
>
> class Book < ActiveRecord::Base
>   has_and_belongs_to_many :words
> end
>
> class Word < ActiveRecord::Base
>    has_and_belongs_to_many :books
> end
>
> I got a Join Tables for has_and_belongs_to_many Associations
>
> class CreateBooksWords < ActiveRecord::Migration
>   def self.up
>     create_table :books_words, :id => false do |t|
>       t.integer :book_id
>       t.integer :word_id
>
>       t.timestamps
>     end
>   end
>
>   def self.down
>     drop_table :books_words
>   end
> end
>
> Now I want to create a form, and user can insert words into a book.
> How do I do that?
There are some conceptual issues here.
If this is in fact a many-to-many relationship between books and words 
so that, a book can have many words, and a word can be in many books, 
then:

Don''t think of "i want to add words to a book", but think of
"I have a
word, and i have a book, and i want to build a relationship between the 
two."
So the form you''re talking about is not a form on words and books, but
a
form about a single model: book_word_relationship (name it whatever you 
like). You will have a relationship_controller which will handle #create 
and #destroy actions. At this point the form should be trivial. The 
#create action will take as parameters the book_id and word_id. Or more 
appropriately @book.book_word_relationships.build(params[:word).

This means you will need a proper model and controller to handle these 
relationships. Which also means that a HABTM relationship is not 
appropriate and you should use has_many
:through=>''relationship''.

This railscast has some good advice about the front-end of a many-many 
relationship: 
http://railscasts.com/episodes/163-self-referential-association
don''t worry about the self-referential part.

-- 
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Weston Platter

2012-Aug-02 15:48 UTC

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Re: How do I create a form for "has_and_belongs_to_many" association?

It sounds like the question has been sufficiently answered.

But if you are looking for more content on the subject, check out the Rails 
Guides on Associations.
http://guides.rubyonrails.org/association_basics.html#the-types-of-associations


On Tuesday, July 31, 2012 2:05:07 PM UTC-5, Ruby-Forum.com User
wrote:>
> Vincent Lin wrote in post #1070656: 
> > git://github.com/vincentopensourcetaiwan/vocabulary.git 
> > This is my source codes. 
> > 
> > I got two models, Book and Word. 
> > 
> > class Book < ActiveRecord::Base 
> >   has_and_belongs_to_many :words 
> > end 
> > 
> > class Word < ActiveRecord::Base 
> >    has_and_belongs_to_many :books 
> > end 
> > 
> > I got a Join Tables for has_and_belongs_to_many Associations 
> > 
> > class CreateBooksWords < ActiveRecord::Migration 
> >   def self.up 
> >     create_table :books_words, :id => false do |t| 
> >       t.integer :book_id 
> >       t.integer :word_id 
> > 
> >       t.timestamps 
> >     end 
> >   end 
> > 
> >   def self.down 
> >     drop_table :books_words 
> >   end 
> > end 
> > 
> > Now I want to create a form, and user can insert words into a book. 
> > How do I do that? 
>
> There are some conceptual issues here. 
> If this is in fact a many-to-many relationship between books and words 
> so that, a book can have many words, and a word can be in many books, 
> then: 
>
> Don''t think of "i want to add words to a book", but
think of "I have a
> word, and i have a book, and i want to build a relationship between the 
> two." 
> So the form you''re talking about is not a form on words and books,
but a
> form about a single model: book_word_relationship (name it whatever you 
> like). You will have a relationship_controller which will handle #create 
> and #destroy actions. At this point the form should be trivial. The 
> #create action will take as parameters the book_id and word_id. Or more 
> appropriately @book.book_word_relationships.build(params[:word). 
>
> This means you will need a proper model and controller to handle these 
> relationships. Which also means that a HABTM relationship is not 
> appropriate and you should use has_many
:through=>''relationship''.
>
> This railscast has some good advice about the front-end of a many-many 
> relationship: 
> http://railscasts.com/episodes/163-self-referential-association 
> don''t worry about the self-referential part. 
>
> -- 
> Posted via http://www.ruby-forum.com/. 
>
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Rails - Jul 2012 - How do I create a form for "has_and_belongs_to_many" association?

How do I create a form for "has_and_belongs_to_many" association?

How do I create a form for "has_and_belongs_to_many" association?

Re: How do I create a form for "has_and_belongs_to_many" association?

Re: How do I create a form for "has_and_belongs_to_many" association?