=CodedAttribute

Two of my favorite MySQL datatypes are ENUMs and SETs. Unfortunately,
ActiveRecord doesn't appear to support these fields well, or provide a good
and simple alternative to the problem of coded values. In the past, I used to
write getters and setters that looked something like this to solve my problem.

  class Article
    STATUS_CODES => {
        :deleted => 0, 0 => :deleted
        :pending => 1, 1 => :pending,
      :completed => 2, 2 => :completed,
      :published => 3, 3 => :published
    }

    def status=(value)
      value = value.to_sym if value.is_a?(String)
      status_code = STATUS_CODES[value]
    end
  
    def status
      STATUS_CODES[status_code]
    end
  end

Doesn't that code look horrible? Wouldn't it be better if it looked like this?!

  class Article
    coded_attribute :status {
      0 => :deleted
      1 => :pending
      2 => :completed
      3 => :published
    end
  end

Or, if we want to get even lazier!

  class MyClass
    coded_attribute :status, [ :deleted, :active, :pending, :deleted ]
  end

If so, then you've come to the right place.

This plugin makes doing all of the above super easy. And your code (and other
programmers) will love you for using it! Like seriously love you!

==Coded Attributes

Lets get down to it. Suppose we have a car, and it can be any one of a variety
of colors. We can indicate this in the model with the following code:

  class Car < ActiveRecord::Base
    coded_attribute :color, [ :red, :orange, :yellow, :green, :blue, :indigo, :violet ]
  end

But we aren't finished just yet. We still need to create a column to store our
attribute data in. There are two ways to go about this.

===Storing the Coded Value

The easiest way to store the coded value is to create an integer column in the
database by appending '_code' to the name of the attribute. So in our 'cars'
table, we could create a 'color_code' integer field. If you do not want to
name the column in your database 'color_code', you can replace :color, with a
:method => :column pair, for example:

  class Car < ActiveRecord::Base
    coded_attribute :color => :color_id, [ :red, orange, :yellow, :green, :blue, :indigo, :violet ]
  end

==Coded Attribute Sets

If you do not want to use a SET datatype, coded_attribute_set an make use of an
integer bitmask to store the values.

  class Car < ActiveRecord::Base
    coded_attribute_set :color, [ :red, :orange, :yellow, :green, :blue, :indigo, :violet ]
  end

=Planned Features

Future versions should hopefully support auto-detecting and setup of enum and
set types (so you don't need to even define the coded_attribute, it will be
done automatically on all classes). 

I also plan on a method added to Migrations that allow you to easily recode data

Copyright (c) 2010 Jaden Carver, released under the MIT license