app/models/result.rb
class Result < ApplicationRecord
belongs_to :swimmer
belongs_to :event
validates :year, presence: true, uniqueness: { scope: %i[event swimmer] }, length: { maximum: 4 }, numericality: { only_integer: true, greater_than_or_equal_to: 2012 }
validates :time, presence: true, length: { maximum: 11 }, numericality: { greater_than: 0.0 }
end