Adam, interesting , what are you thoughts about when I want to return all books by instance_id.. won't that kill the db looking at the user's table?
On Sep 7, 9:54 pm, Adam <[email protected]> wrote: > On Tue, Sep 7, 2010 at 11:41 PM, nobosh <[email protected]> wrote: > > Adam, > > > Thanks for the answer, let me add a little color as to what I'm trying > > to get working: > > > I have the following models: Users (id, name, email, instance_id, > > etc...) Instances (id, domain name) Books (id, name, user_id, > > instance_id) > > In Rails 3, When a new book is created, I need the user_id, and > > instance_id to be populated based on the current_user. > > Currently, user_id is being assigned when I create a new book but not > > instance_id? > > > class Instance < ActiveRecord::Base > > has_many :users > > has_many :books, :through => :users, :order => "created_at DESC" > > end > > > class User < ActiveRecord::Base > > belongs_to :instance > > has_many :books, :order => "created_at DESC" > > end > > > class Book < ActiveRecord::Base > > belongs_to :user > > has_one :instance, :through => :user > > end > > > Thoughts on this? I'm a newbie so I'd love to hear if I going down the > > right track or not... > > There's a discrepancy there - Book has_one instance, but it has an > instance_id. The foreign key goes with a belongs_to relationship. > > The Instance is related to the User, so storing it in two places (once on > the User, once on the Book) can only cause maintenance problems down the > line. Better to store it one place (like on the User, which you do now) and > let the Book retrieve its Instance through the User. > > In other words, books should not have an instance_id column. It's unused - > the relationship is achieved through the has_one relationship set up in the > Book model. -- You received this message because you are subscribed to the Google Groups "Ruby on Rails: Talk" group. To post to this group, send email to [email protected]. To unsubscribe from this group, send email to [email protected]. For more options, visit this group at http://groups.google.com/group/rubyonrails-talk?hl=en.
