Nested Options and Slick

TestNestedClasses.scala

package models
import slick.lifted.Tag

trait Test {
  val profile: slick.driver.JdbcProfile
  import profile.simple._

  /**
   * The wrapper class has an optional quantity field
   * which itself has an optional size field
   */
  case class Wrapper(id: Option[Long], quantity: Option[Quantity])
  case class Quantity(size: Option[Int])

  class Wrappers(_tableTag: Tag) extends Table[Wrapper](_tableTag, "wrappers") {

    val id: Column[Long] = column[Long]("id", O.AutoInc, O.PrimaryKey)
    val aField = column[Option[Int]]("aField")

    def * = (
      id.?,
      aField
    ) <> ((columns2Wrapper _).tupled, wrapper2Columns)

    def columns2Wrapper(id: Option[Long], a: Option[Int]): Wrapper =
      Wrapper(id, for (size <- a) yield Quantity(a))

    def wrapper2Columns(f: Wrapper) =
      Some((f.id, f.quantity.map(_.size)))
  }

}