hasManyThrough.scala

case class Item(
  id: Option[Long],
  code: String,
  name: String,
  url: String,
  imageUrl: String,
  price: Int,
  createAt: DateTime,
  updateAt: DateTime,
  users: Seq[User] = Seq.empty
)

object Item extends SkinnyCRUDMapper[Item] {

  override def tableName: String = "items"

  override def defaultAlias: Alias[Item] = createAlias("i")
// snip
}

case class ItemUser(id: Option[Long],
                    itemId: Long,
                    userId: Long,
                    `type`: String,
                    createAt: DateTime,
                    updateAt: DateTime
                   ) extends SkinnyJoinTable[ItemUser] {
  override def defaultAlias: Alias[ItemUser] = createAlias("iu")
}

case class User(
                 id: Option[Long] = None,
                 name: String,
                 email: String,
                 password: String,
                 createAt: DateTime = DateTime.now(),
                 updateAt: DateTime = DateTime.now(),
                 items: Seq[Item] = Seq.empty
               )

object User extends SkinnyCRUDMapper[User] {

  override def tableName = "users"

  override def defaultAlias: Alias[User] = createAlias("u")

  val allItems: HasManyAssociation[User] = hasManyThrough[Item](
    through = ItemUser,
    many = Item,
    merge = (user, items) => user.copy(items = items)
  )
  
  // `type`がwantの場合のみのレコードとジョインしたい
  
}