column_reader.rb

module ColumnReader
  def column_reader(column_name, options = {})
    name = options.delete(:as) || column_name.to_s.pluralize
    column = columns_hash[column_name.to_s]
  
    self.module_eval %{
      def self.#{name}
        query = scoped.arel.project(arel_table[:#{column_name}])
        connection.select_all(query.to_sql).collect do |value| 
          v = value.values.first
          #{column.type_cast_code('v')}
        end
      end
    }
  end

  ActiveRecord::Base.extend(self)
end