gistfile1.rb

irb(main):010:0> a = KioskConfiguration.with_computer_id('00-50-E4-00-0E-C6').count
   (2.6ms)  SELECT COUNT(*) FROM "kiosk_configurations" WHERE "kiosk_configurations"."deleted_at" IS NULL AND "kiosk_configurations"."computer_id" = $1  [["computer_id", "00-50-E4-00-0E-C6"]]
=> 0

irb(main):011:0> KioskConfiguration.all.map &:computer_id
  KioskConfiguration Load (3.9ms)  SELECT "kiosk_configurations".* FROM "kiosk_configurations" WHERE "kiosk_configurations"."deleted_at" IS NULL
=> ["78-31-c1-cf-fd-12", "00-50-E4-00-0E-AC"]

irb(main):044:0> kc = KioskConfiguration.create computer_id: '00-50-E4-00-0E-C6'
   (2.1ms)  BEGIN
  KioskConfiguration Exists (2.0ms)  SELECT  1 AS one FROM "kiosk_configurations" WHERE "kiosk_configurations"."computer_id" = '00-50-E4-00-0E-C6' LIMIT 1
   (2.2ms)  ROLLBACK
   (2.2ms)  ROLLBACK
=> #<KioskConfiguration id: nil, bearing: nil, centre_id: "", computer_id: "00-50-E4-00-0E-C6", kiosk_id: nil, languages: [], ui_state: 3, ui_state_changed_at: nil, deleted_at: nil, created_at: nil, updated_at: nil>

irb(main):047:0> kc.errors[:computer_id]
=> ["has already been taken"]