gistfile1.rbx

# Allows usage of the following syntax:
# Model.find :conditions => {:field => NotNull}

class NotNullClass
  def map(*a, &b)
    [].map(*a, &b)
  end
  
  def empty?
    true
  end
end

NotNull = NotNullClass.new

module ActiveRecord
  class Base
    class << self
      def attribute_condition_with_not_null(argument)  
        case argument
        when NotNullClass then "IS NOT ?"
        else
          attribute_condition_without_not_null(argument)
        end
      end
  
      alias_method_chain :attribute_condition, :not_null
    end
  end
end