Add an auto incrementing field to your Mongoid::Document
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Latest commit 76c7c7e May 17, 2012 @jffjs jffjs added changelog



Add SQL like auto-incrementing fields to your Mongoid documents.

This gem is inspired by and the mongomapper_id2 gem.


In your Gemfile:

gem 'mongoid_auto_inc'

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

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: