活动记录加入 Rails 3.1

Question

Trying to return all comments associated with articles written by a particular user. The following code gives me the error:

undefined method `joins' for #<User:0x000001042c8bc0>

under Rails 3.1

class User
  has_many :articles

  def comments
    self.joins(:articles => :comments)
  end

end

Answer 1

You probably want a has_many:through here.

class User
  has_many :articles
  has_many :comments, :through => :articles
end