Rails与蒙古语的多态关联

Question

Using Rails 3.2 with Mongoid 3.1.5. I recently just changed the Event belongs_to :venue into a polymorphic association :location. After doing this, when saving the event scoped from the Organization, it no longer associates the event to the venue.

#Models
class Event
  include Mongoid::Document
  has_and_belongs_to_many :organizations, index: true
  belongs_to :location, polymorphic: true, index: true
end

class Organization
  include Mongoid::Document
  has_and_belongs_to_many :events, index: true
end

class Venue
  include Mongoid::Document
  has_many :events, as: :location, autosave: true
end

#Code

org = Organization.first
ven = Venue.first
evt = org.events.create(location: ven)
org.events.count #=> 1
evt.location #=> #<Venue...

# How can I make this include the evt?
ven.events.count #=> 0

From this, I could just do ven.events << evt , but that would require me doing that every time. Any other ideas out there?

Answer 1

There is no "join" on Mongodb, so it is impossible to eager load your relationship. You can denormalize your data and embed a copy document from Venue inside the Event.