Using models in your migrations

When, you are coding data migrations, and decide to use model classes in your migrations. You are asking for trouble. Why?

Because, migrations is a fluid thing, and say you have decided to get rid of your model all together,then your migrations would magically start failing. This could be a problem.

Toolamantim, suggests an alternative. Simply redefine your models inside migrations itself:

#  class Product < ActiveRecord::Base; end
# class SoftwareProduct < Product; end
# class CourseProduct < Product; end
#
# def self.up
# add_column :products, :position, :integer
# Product.reset_column_information
#
# # Set default list orders
# SoftwareProduct.find(:all).inject(0) do |i,p|
# p.update_attribute(:position, i)
# i+1
# end
# CourseProduct.find(:all).inject(0) do |i,p|
# p.update_attribute(:position, i)
# i+1
# end
# end
#
# def self.down
# remove_column :products, :position
# end