Add SQL like auto-incrementing fields to your Mongoid documents.
This gem is inspired by ihswebdesign.com/blog/autoincrement-in-mongodb-with-ruby/ and the mongomapper_id2 gem.
In your Gemfile:
Followed by running bundle install, or do:
gem install mongoid_auto_inc
Just add auto_increment :field to your Mongoid model where :field is the name of the auto-incremented field you want to create. Example:
class Book include Mongoid::Document field :title field :author auto_increment :sequence end
auto_increment :sequence will create a field of type Integer named sequence for Book. Whenever an instance of the model is created (intially saved to mongoDB), the auto_increment field will automatically be set to the next number in the sequence.
You can add more than one auto-incremented field per model.
auto_increment :sequence, :collection => :some_collection
mongoid_auto_inc keeps track of the current number in the sequence by creating a separate document mongoDB to query and update. By default auto_increment will save this document to a mongoDB collection called sequences. If you wish to save to a different collection use the :collection option to specify its name.
auto_increment :sequence, :seed => 3333
Use the :seed option to set the initial value of the auto-incremented field. The first number assigned from the sequence will be the next number after the seed value.
Thanks to these folk for their help: