Hi,
I’m trying to validate the uniqueness of a value in a model where a
user has_one item. When the record is created, this isn’t a problem
as I just use validate_uniqueness_of. However, on update, I need to
be able to bill the user the difference between their existing item
and their new amount:
class Item < CachedModel
attr_accessor :bidup
belongs_to :user
…
validates_uniqueness_of :value, :message => “Somebody’s already got
that spot. Nudge it by 1 and try again.”
…
def after_save
deduct_payment(self.value) if !bidup?
deduct_payment(self.bidup) if bidup?
end
def save
self.value += self.bidup if bidup?
begin
super
rescue ActiveRecord::StatementInvalid => error
errors.add(:value, “Somebody’s already got that spot. Nudge it
by 1 and try again.”)
return false
end
end
protected
def bidup?
!self.bidup.blank?
end
end
This works fine on create, but when I call
Item.update_attribute(:bidup, ) it raises
“ArgumentError: wrong number of arguments (1 for 0)”. I’m not deeply
attached to this way of doing things and would welcome any
suggestions.
Cheers,
Todd