VersionedRecord

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Versioned Record allows the creation of multiple versions of an active record that share an ID. The version and ID columns of a record form a composite primary key and as such this gem relies on the composite_primary_keys gem.

Why another versioning tool for ActiveRecord? Mainly because this gem does not rely on serializing data or storing of multiple attributes in a single column. It uses databases as they were intended which means it is fast, reliable and flexible.

Installation

Add this line to your application's Gemfile:

gem 'versioned_record'

And then execute:

$ bundle

Or install it yourself as:

$ gem install versioned_record

Usage

Setting up your table

To create a versioned record, start by adding the versioned: true option to your migration and then (re)running.

create_table :products, versioned: true do |t|
  t.string :name
  t.decimal :price
end

The versioned option will create the id, version and is_current_version columns and create a composite primary key on the id and version columns.

Next, include the VersionedRecord module in your ActiveRecord model

class Product < ActiveRecord::Base
  include VersionedRecord
end

Creating records and versions

Creating a record happens as normal.

product = Product.create(name: 'Coffee Cup', price: 4.99)

The product will have version set to 0 and is_current_version set to true

product.version => 0
product.is_current_version? => true

To create a version simply call create_version! on the record.

product_v2 = product.create_version!(price: 5.99)

Note that any attributes not specified in the create_version! call will be copied from the previous version.

product_v2.name => 'Coffee Cup'

Also, the is_current_version flag is unset for the old version and set for the new one

product.is_current_version? => false
product_v2.is_current_version? => true

TODO: Associations

Database Support

Right now, only PostgreSQL has been tested. MySQL may or may not work but if you'd like to test/add support please fork and contribute!

Limitations

Does not currently work with ActiveRecord 4.1+

Author

Dan Draper, dan at codehire dot com, Codehire, @danieldraper

Contributing

  1. Fork it
  2. Create your feature branch (git checkout -b my-new-feature)
  3. Commit your changes (git commit -am 'Add some feature')
  4. Push to the branch (git push origin my-new-feature)
  5. Create new Pull Request