class Frequency < ActiveRecord::Base attr_accessible :delay, :description, :helpmsg, :name, :prefix, :activate # Relation has_many :bans, :dependent => :destroy, :inverse_of => :frequency accepts_nested_attributes_for :bans, :allow_destroy => true # Validation before_destroy :raise_if_last def raise_if_last if Frequency.count < 3 raise "Can't delete last two frequencies" end end end