永続化の前後をクラスで表現する

1.scala

case class Person(name: String, age: Int)

2.scala

case class Person(id: Int, name: String, age: Int)

3.scala

case class Person(id: Option[Int], name: String, age: Int)

4.scala

sealed trait Person {
  val name: String
  val age: Int
}

case class IdentifiedPerson(id: Int, name: String, age: Int) extends Person
case class UnIdentifiedPerson(name: String, age: Int) extends Person