Rails greater_than model validation against model attribute

Question

I\'ve got a Trip model, which among other attributes has a start_odometer and end_odometer value. In my model, i\'d like to validate that the end odometer is larger than the st

Answer 1

You'll probably need to write a custom validation method in your model for this...

validate :odometer_value_order

def odometer_value_order
  if self.end_odometer && (self.start_odometer > self.end_odometer)
    self.errors.add_to_base("End odometer value must be greater than start odometer value.")
  end
end