How can one Validate presence of only one?

Question

I have a user model that has_one signup.

I'm having a recurring bug where users will click multiple times and create many unnecessary signups. How can I validate the user only gets one? Is there a way to do that from the model?

Answer 1

In rails 3 you could do like this.

validates :field, :uniqueness => true

If you want your custom message then

validates :field, :uniqueness => {:message => 'your message'}

Answer 2

Not sure about your model, but validates_uniqueness_of might be what you are looking for.