How to get Mongoid working with existing MongoDB collcetions? - ruby-on-rails-3

Question

I'm working on a quite simple ruby on rails website using MongoDB as the database. My idea was to get this website working with Mongoid such that I can display certain contents from the already existing mongodb collection. I've checked the Internet for tutorials about how to use Mongoid, the problem is all of them are about how to create your Mongodb with rails rather than using an existing one. Could anyone tell how to do what I want? Thanks a lot.

Answer 1

Until you define models for your collections,
you will have to drop down to the Moped driver level to examine existing collections.
Here's a link to the Moped documentation - http://mongoid.org/en/moped/docs/driver.html
And here are some hints to get you started.
console-input.rb
session = Mongoid.default_session
collection = session['test_collection']
collection.insert({name: 'George Washington'})
session.collection_names
collection.find.first
$ rails c < console-input.rb
Loading development environment (Rails 3.2.14)
Switch to inspect mode.
session = Mongoid.default_session
<Moped::Session seeds=["localhost:27017"] database=sandbox_mongoid3_development>
collection = session['test_collection']
#<Moped::Collection:0x007ff2ceb73c20 #database=#<Moped::Database:0x007ff2ceb68b40 #session=<Moped::Session seeds=["localhost:27017"] database=sandbox_mongoid3_development>, #name="sandbox_mongoid3_development">, #name="test_collection">
collection.insert({name: 'George Washington'})
nil
session.collection_names
["test_collection"]
collection.find.first
{"_id"=>"528bdc60e277b0dd1681771a", "name"=>"George Washington"}