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:
don't worry about the self-referential part.