Mongoid3 Sequence

Mongoid3 Sequence allows you to specify fields to behave like a sequence number (exactly like the "id" column in conventional SQL flavors).

Mongoid3 Sequence works with Mongoid > 3.x, and is not backward compatible. There are other Mongoid sequence gems that sequences the _id field, but with this gem, you can assign any field as sequenced.

Credits

This gem is derived from Mongoid Sequence Gem by goncalossilva.

General Usage

Include Mongoid::Sequence in your class and call sequence(:field).

Like this:

class Sequenced
	include Mongoid::Document
	include Mongoid::Sequence

	field :my_sequence, :type => Integer
	sequence :my_sequence
end

s1 = Sequenced.create
s1.sequence #=> 1

s2 = Sequenced.create
s2.sequence #=> 2 # and so on

_id Field Usage

You can auto-assign sequenced ID to Mongod's _id field. Note that you have to declare _id is Integer type. This is because Mongoid3 defaults to treating _id as string, which will cause mongoid _id queries to return nil. i.e. in the example below, Sequenced.where( _id: "2" ) will return nil.

class Sequenced
	include Mongoid::Document
	include Mongoid::Sequence

  field :_id, type Integer
	sequence :_id
end

s1 = Sequenced.create
s1.id #=> 1

s2 = Sequenced.create
s2.id #=> 2 # and so on

Consistency

Mongoid::Sequence uses the atomic findAndModify command, so you shouldn't have to worry about the sequence's consistency.

Installation

Add it to your projects' Gemfile:

gem 'mongoid3-sequence', git: 'git://github.com/akiatoji/mongoid3-sequence.git'

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Copyright © 2013 Aki Atoji, released under the MIT license