belongs_to_versioned

The purpose of belongs_to_versioned is to save version information as used by the acts_as_versioned[http://github.com/technoweenie/acts_as_versioned/tree/master] plugin by technoweenie alongside belongs_to ActiveRecord associations.

Installation

script/plugin install git://github.com/laserlemon/belongs_to_versioned.git

Example

In your migrations:

create_table :products do |t|
  t.string :name
  t.text :description
  t.integer :price
  t.integer :version
  t.timestamps
end
Product.create_versioned_table

create_table :line_items do |t|
  t.belongs_to :product
  t.integer :product_version
  t.integer :quantity
  t.timestamps
end

In your models:

class Product < ActiveRecord::Base
  validates_presence_of :name, :description, :price
  validates_numericality_of :price, :greater_than_or_equal_to => 0, :only_integer => true

  acts_as_versioned :if_changed => [:price]

  has_many :line_items
end

class LineItem < ActiveRecord::Base
  validates_presence_of :product, :quantity
  validates_numericality_of :quantity, :greater_than => 0, :only_integer => true

  belongs_to_versioned :product

  def subtotal
    product.price * quantity
  end
end

In your controller:

product = Product.create(
  :name => 'Settlers of Catan',
  :description => 'Lorem ipsum dolor sit amet, consectetur adipisicing elit, sed do eiusmod tempor incididunt ut labore et dolore magna aliqua.',
  :price => 3999
)
@line_items = []
@line_items << LineItem.create(:product => product, :quantity => 1)
product.update_attributes(:price => 2999)
@line_items << LineItem.create(:product => product, :quantity => 1)

In your view:

<table>
  <tr>
    <th>Quantity</th>
    <th>Product</th>
    <th>Price</th>
    <th>Subtotal</th>
  </tr>
  <%- @line_items.each do |line_item| -%>
  <tr>
    <td><%= line_item.quantity %></td>
    <td><%=h line_item.product.name %></td>
    <td><%= number_to_currency(line_item.product.price.to_f / 100) %></td>
    <td><%= number_to_currency(line_item.subtotal.to_f / 100) %></td>
  </tr>
  <%- end -%>
</table>

Tips

• As an alternative to the belongs_to_versioned method, you can pass a :versioned => true option to a typical belongs_to association.

• The :revert_to option is an optional string specifying the column name to use when reverting the parent object. This defaults to the name of the association appended by "_version".

• If the :revert_to value is a symbol, that acts_as_versioned extension method will be used when reverting the parent object (i.e. :earliest).