Rails关联

架构:

收件人\u id

class Message
  belongs_to :sender, :class_name => 'User'
  belongs_to :recipient, :class_name => 'User'
end


class User
  has_many :sent_messages, :class_name => 'Message', :foreign_key => :sender_id
  has_many :income_messages, :class_name => 'Message', :foreign_key => :recipient_id
end