Lift Mapper - 具有 OneToMany 映射的特征

Question

更新：更改示例以反映我当前的情况

相当新，我正在尝试为我的应用程序创建一个模型。因为我想保持 DRY 的精神，所以我想使用特征混合来指定模型中的一些字段。例如，我有一个 Person 特征，我将其混合到我的 Employee 类中：

trait Person[T <: LongKeyedMapper[T]] extends LongKeyedMapper[T]{
  self: T =>
  object firstName extends MappedString[T](this, 50)
  object lastName extends MappedString[T](this, 50)
  object civicRegNumber extends MappedString[T](this, 12)
}

class Employee extends IdPK with OneToMany[Long, Employee] with Person[Employee] {
  def getSingleton = Employee

  object contactInfos extends MappedOneToMany(EmployeeContactInfo, EmployeeContactInfo.person) 
}

object Employee extends Employee with LongKeyedMetaMapper[Employee] 

可以看出，我在 Employee 中有一个 contactInfos 多对一映射。它看起来像：

trait PersonContactInfo[T <: LongKeyedMapper[T],P <: Person[P]] extends LongKeyedMapper[T] {
  self: T =>
  object email extends MappedEmail[T](this, 80)
  def personMeta:P with LongKeyedMetaMapper[P]
  object person extends LongMappedMapper[T,P](this, personMeta)
}

class EmployeeContactInfo extends IdPK with PersonContactInfo[EmployeeContactInfo, Employee] {
  def getSingleton = EmployeeContactInfo
  val personMeta = Employee

}
object EmployeeContactInfo extends  EmployeeContactInfo with LongKeyedMetaMapper[EmployeeContactInfo]

这似乎有效，但我想将 contactInfos 对象移动到我的 Person 特征中。但是，我不知道如何实现这一点...是否有可能从特征继承 OneToMany 映射？欢迎任何帮助！

Answer 1

经过几次尝试后，我通过分离执行 Person 到 PersonContactInfo 的 OneToMany 映射的特征来实现此目的。这就是它现在的样子

trait Person[T <: Person[T]] extends LongKeyedMapper[T]{
  self: T =>
  object firstName extends MappedString[T](this, 50)
  object lastName extends MappedString[T](this, 50)
  object civicRegNumber extends MappedString[T](this, 12)
}

trait PersonToPersonContacts[P <: Person[P], PCI <: PersonContactInfo[PCI, P]] extends OneToMany[Long,P] {
  self: P =>
  def contactInfoMeta:LongKeyedMetaMapper[PCI] with PCI
  object contactInfos extends MappedOneToMany(contactInfoMeta, contactInfoMeta.person)
}

class Employee extends IdPK with Person[Employee]  with PersonToPersonContacts[Employee, EmployeeContactInfo] {
  def getSingleton = Employee
  override def contactInfoMeta = EmployeeContactInfo
}
object Employee extends Employee with LongKeyedMetaMapper[Employee] 

，我的 PersonContactInfo 现在看起来像：

trait PersonContactInfo[T <: LongKeyedMapper[T],P <: Person[P]] extends LongKeyedMapper[T] {
  self: T =>
  object email extends MappedEmail[T](this, 80)
  def personMeta:P with LongKeyedMetaMapper[P]
  object person extends LongMappedMapper[T,P](this, personMeta)
}

class EmployeeContactInfo extends IdPK with PersonContactInfo[EmployeeContactInfo, Employee] {
  def getSingleton = EmployeeContactInfo

  val personMeta = Employee

}
object EmployeeContactInfo extends  EmployeeContactInfo with LongKeyedMetaMapper[EmployeeContactInfo]

仍然不确定这是否是解决这个问题的方法，但 ity 可以完成这项工作:)