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PORuby on Rails: has_many referential --which model objects does it own?
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2011-08-30T08:28:45.830
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I am new to Rails and finished Michael Hartl's "Ruby on Rails 3 Tutorial". Although the book teaches me a lot, I find this puzzle I don't understand. To preview the puzzle, that is, I don't understand, inside User model, <pre><code>has_many :following, :through=>:relationship, :source=>:followed </code></pre> how this piece of code link "user.following" to an array of User instances. And below is the whole puzzle. First of all, I have the Relationship model, which records followed_id and follower_id infos. Inside Relationship model, the association is simple as <pre><code>class Relationship < ActiveRecord::Base attr_accessible :followed_id belongs_to :follower, :class_name => "User" belongs_to :followed, :class_name => "User" end </code></pre> Then, inside the User model, a user will assume the role of follower, and collect all its following rows in relationships table through relationships association. <pre><code>class User < ActiveRecord::Base . . . has_many :relationships, :foreign_key => "follower_id", :dependent => :destroy . </code></pre> Until now, I got it. But confusion came at the next line, where through user.following it can assemble all that user's following(User instances). Like so, <pre><code>has_many :following, :through=>:relationships, :source=>:followed </code></pre> I understand that :source=>:followed will overwrite the default, and let find all followed_ids associated with that user. But, how can Rails recognize followed_id to link to User object? The label name doesn't match users, nor is there :class_name specified. I just don't get how Rails do this underlying work, or I missed out some hints. Thank you! :)
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<ruby-on-rails-3><model><has-many><model-associations>
Title
Ruby on Rails: has_many referential --which model objects does it own?
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