caroo / enum_column

Enum column support for Rails 3

Overview

  This gem is a ROR extension to support enumerations in the database schema using the enum type in MySQL. Currently only MySQL is implemented.
  Tested with Rails 3, for Rails 2 you should better use enum-column plugin (http://rubyforge.org/projects/enum-column/)

How to use it.

In you Gemfile:

  gem 'enum_column', :git => 'git://github.com/electronick/enum_column.git'


In your schema:

  When you create your schema, specify the constraint as a limit:

    create_table :enumerations, :force => true do |t|
      t.column :severity, :enum, :limit => [:low, :medium, :high, :critical], :default => :medium
      t.column :color, :enum, :limit => [:red, :blue, :green, :yellow]
      ...
    end


In the model:

  You can then automatically validate this column using:

    validates_columns :severity, :color

  The rest will be handled for you. All enumerated values will be given as symbols.

    @e = Enumeration.new
    @e.severity = :low

You can always use the column reflection to get the list of possible values from the database column.

    Enumeration.columns_hash['color'].limit
    or
    @enumeration.column_for_attribute(:question_type).limit
    
    Will yield: [:red, :blue, :green, :yellow]