Ruby On Rails validates_uniqueness_of具有范围和日期范围

Question

Is it possible to use validates_uniqueness_of cars only in the case when car.created_at is > 6.months.ago?

In my case,

validates_uniqueness_of :car, :scope => [:dealer_id, :type], :on => :create

should allow to create a car for the same dealer_id and with the same type only if last created car with this data was created more then 6.months.ago

Answer 1

You can probably do something like this.

validate :be_a_new_car, :on=>:create

def be_a_new_car
 old_car = self.class.where(:car=>self.car,:dealer_id=>self.dealer_id,:type=>self.type)
           .where("created_at < ?",6.months.ago).first
 self.errors.add(:car, "not old enough to be unique") if old_car
end