ConsumableSequence
==================

Given an optional scope, will return a sequence number that is guaranteed to be unique and consumable. Useful for (among other things) when you need to generate an ID or part of an ID without using auto_increment (before record is created for example) - things like custom order numbers, etc


Example
=======

ConsumableSequence.get # => 1
ConsumableSequence.get # => 2
ConsumableSequence.get('Order') #=> 1


Instructions
============

-- migration

def self.up
  create_table :consumable_sequences do |t|
    t.string scope, :unique => true, :null => false
    t.integer sequence, :null => false
  end
  add_index "consumable_sequences", ["scope"], :name => "index_consumable_sequences_on_scope", :unique => true
  
  # optional
  # ConsumableSequence.offset('my_key',409)
end

def self.down
  remove_index "consumable_sequences", :name => "index_consumable_sequences_on_scope"
  drop_table :consumable_sequences
end


Copyright (c) 2009 Darcy, released under the MIT license