Question

I have the following polymorphic associations:

class Invite < ActiveRecord::Base
  belongs_to :inviteable, :polymorphic => true 

class Event < ActiveRecord::Base
  has_many :invites, :as => :inviteable, :dependent => :destroy

class Team < ActiveRecord::Base
  has_many :invites, :as => :inviteable, :dependent => :destroy

I’m trying to create scopes on Invites specific to events, and to future events:

(in Invite.rb)
  scope :to_events, where('inviteable_type = ?', "Event")
  scope :to_future_events, lambda { self.to_events.joins("join events").where('events.starttime > ?', Time.now) }

The to_events scope works fine; the to_future_events returns the correct subset of invites, but it returns many copies of each. Any idea why? Is there a cleaner/Rails-ier way to accomplish what i’m trying to accomplish?

Answer 1

You have to provide an ON statement for the join:

scope :to_future_events, lambda { self.to_events.joins("join events on events.id = invites.inviteable_id").where('events.starttime > ?', Time.now) }

Otherwise it joins every invite record with every events record.