How to directly access MongoDB API from Mongoid?

I'd like to use t开发者_如何学Pythonhe addToSet method of MongoDB, but Mongoid doesn't currently support this yet. Is there a way of directly accessing the MongoDB driver from my Rails model?

I asked this question on Mongoid group and this was the best response:

Assuming your model object is a Mongoid::Document, simply call the "db" method on it to get a handle to the Mongo::DB object that Mongoid is using under the hood.

http://rdoc.info/github/mongoid/mongoid/master/Mongoid/Collections/Cl...

From there, you can use the MongoDB Ruby driver API directly.

http://api.mongodb.org/ruby/current/file.TUTORIAL.html#

Also, you can access the record collection using ModelName.collection.

You can use the mongo-ruby-driver gem from mongodb:

https://github.com/mongodb/mongo-ruby-driver

Check the update method in the api:

http://api.mongodb.org/ruby/1.2.0/Mongo/Collection.html#update-instance_method

And this option might be what you're looking for to use addToSet:

(Boolean) :upsert — default: +false+ — if true, performs an upsert (update or insert)

Up to and including Mongoid 2.4 you could access the database object with

db = Mongoid.master