Overview
This gem is an extension to ActiveRecord which enables native support of 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/)
Works with Scaffolding.
Supported adapters:
mysql
mysql2
jdbcmysql (by Nilesh Trivedi)
How to use it.
In you Gemfile:
gem 'enum_column3'
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 = :medium
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(:color).limit
Will yield: [:red, :blue, :green, :yellow]
In views:
You can use enum_select helper to generate input for enumerated attribute as:
<%= enum_select(@enumeration, 'severity')%>
or
<%= form_for @enumeration do |f| %>
<%= f.label :severity %>
<%= f.enum_select :severity %>
<% end %>