gistfile1.txt

require "dm-core"

DataMapper::Logger.new($stdout, :debug)
DataMapper.setup(:default, 'mysql://test@localhost/dm_test')

class Amount
  include DataMapper::Resource

  property :id,         Serial
  property :amount_1,   Integer
  property :amount_2,   Integer
end

DataMapper.auto_migrate!
Amount.create(:amount_1 => 10, :amount_2 => 20)
Amount.create(:amount_1 => 20, :amount_2 => 20)

p Amount.all(:conditions => ['amount1 = amount2'])




 ~ (0.000003) CREATE TABLE `amounts` (`id` INT(10) UNSIGNED NOT NULL AUTO_INCREMENT, `amount_1` INTEGER, `amount_2` INTEGER, PRIMARY KEY(`id`)) ENGINE = InnoDB CHARACTER SET utf8 COLLATE utf8_general_ci
 ~ (0.000004) INSERT INTO `amounts` (`amount_1`, `amount_2`) VALUES (10, 20)
 ~ (0.000004) INSERT INTO `amounts` (`amount_1`, `amount_2`) VALUES (20, 20)
 ~ (0.000004) SELECT `id`, `amount_1`, `amount_2` FROM `amounts` ORDER BY `id`
[#<Amount @id=1 @amount_1=10 @amount_2=20>, #<Amount @id=2 @amount_1=20 @amount_2=20>]