Question

So, I am having some issues with user authentication in embedded documents. I have two documents, one embedded in the other. A business has many members. The models look like this:

class Member
  include Mongoid::Document

  field :username,        type: String
  field :password,           type: String
  embedded_in :business

  validates :username,  :presence => true, :uniqueness => true, :length => 5..60
end

class Business
  include Mongoid::Document

  field :name,            type: String
  embeds_many :members
end

The problem is that it isn’t validating the username’s uniqueness in each model. When I save a member within a business, I can save a thousand of the same name. This of course is not going to work for a good authentication system. I am using Mongoid 2, Rails 3, and Ruby 1.9

Answer 1

This is a normal behavior when using embedded documents as explained here: MongoID validation

validates_uniqueness_of

Validate that the field is unique in the database: Note that for
embedded documents, this will only check that the field is unique
within the context of the parent document, not the entire database.

I think you want to try to create an Index in the username field that would ensure uniqueness among all the objects of that collection. Something like this:

ensureIndex({username:1},{unique:true}); 

EDIT: If you want Mongo to throw exception if a document with the same index value exists, you must avoid Mongo to do the “fire and forget” pattern. This means that the database will not wait for a response when you perform an update/write operation on a document.

And you want to pass this parameter: safe:true. By doing so Mongo should raise an exception if for any reason the document can’t be inserted.