Contents

== Description

Given the following class definitions,

  class Address
    belongs_to :addressable, :polymorphic => true
  end

  class Person
    has_many :addresses, :as => addressable
  end

  class Vendor < Person
  end

and given the following code,

  vendor = Vendor.create(...)
  address = vendor.addresses.create(...)

  p vendor
  p address

will output,

  #<Vendor id: 1, type: "Vendor" ...>
  #<Address id: 1, addressable_id: 1, addressable_type: 'Person' ...>

Notice that addressable_type column is Person even though the actual class is Vendor. 

Normally, this isn't a problem, however it can have negative performance characteristic in certain circumstances. The most obvious one is that
a join with persons or an extra query is required to find out the actual type of addressable.

This gem add ActiveRecord::Base.store_base_sti_class configuration option. It defaults to true for backwards compatibility. Setting it false will alter ActiveRecord's behavior to store the actual class in polymorphic _type columns when STI is used.

In the example above, if the ActiveRecord::Base.store_base_sti_class is false, the output will be,

  #<Vendor id: 1, type: "Vendor" ...>
  #<Address id: 1, addressable_id: 1, addressable_type: 'Vendor' ...>

== Usage

Add the following line to your Gemfile,

  gem 'store_base_sti_class_for_3_1'

then bundle install. Once you have the gem installed, add the following to one of the initializers (or make a new one) in config/initializers,

  ActiveRecord::Base.store_base_sti_class = false

When changing this behavior you will have write a migration to update all of your existing _type columns accordingly. You may also need to change your application if it explicitly relies on the _type columns.

== Notes

The gem has used the test cases from https://github.com/pkmiec/store_base_sti_class_for_3_0, but has been completely rewritten for 3.1.  It currently works with ActiveRecord 3.1.0 through 3.1.3.

== Copyright

Copyright (c) 2011 AppFolio, inc. See LICENSE.txt for
further details.

Version data entries

1 entries across 1 versions & 1 rubygems

Version	Path
store_base_sti_class_for_3_1-0.0.1	README.rdoc