get counter nested model mongoid

[Maria Serrano Cáceres]

2 models:

Class User
include Mongoid::Document
has_many :reports
end

Class Report
include Mongoid::Document
belongs_to :user
end

I need a query to get all users have 6 or more reports, something like:.

Users.where(reports.count > 5)

How can I do it?

Thank you very much!

[Durran Jordan]

This query is not possible since MongoDB does not have joins. You would need to store a "counter cache" for reports on the User in order to do so. A quick and dirty example:

class User
  include Mongoid::Document
  field :reports_count, type: Integer
  has_many :reports
end

class Report

  include Mongoid::Document
  belongs_to :user

  after_create do |doc|
    doc.user.inc(:reports_count, 1)
  end

  after_destroy do |doc|
    doc.user.inc(:reports_count, -1)
  end
end

2012/11/5 Maria Serrano Cáceres <maserran...@gmail.com>

[Maria Serrano Cáceres]

Thank you Durrand. Is valid for this example instead use this code use this gem https://github.com/jah2488/mongoid-magic-counter-cache

Thank you very much again Durrand!.