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尝试与Sangria和Slick合作。对他们俩来说都是新手。

我有一堆表格，它们共享一个公共字段列表。Slick 对此的表示如下：

case class CommonFields(created_by: Int = 0, is_deleted: Boolean = false)

trait CommonModel {
  def commonFields: CommonFields
  def created_by = commonFields.created_by
  def is_deleted = commonFields.is_deleted
}

case class User(id: Int,
                name: String,
                commonFields: CommonFields = CommonFields()) extends CommonModel

光滑的桌子：

  abstract class CommonTable [Model <: CommonModel] (tag: Tag, tableName: String) extends Table[Model](tag, tableName) {
    def created_by = column[Int]("created_by")
    def is_deleted = column[Boolean]("is_deleted")
  }

  case class CommonColumns(created_by: Rep[Int], is_deleted: Rep[Boolean])

  implicit object CommonShape extends CaseClassShape(
    CommonColumns.tupled, CommonFields.tupled
  )

  class UsersTable(tag: Tag) extends CommonTable[User](tag, "USERS") {
    def id = column[Int]("ID", O.PrimaryKey, O.AutoInc)
    def name = column[String]("NAME")

    def * = (id,
      name,
      CommonColumns(created_by, is_deleted)) <> (User.tupled, User.unapply)
  }

  val Users = TableQuery[UsersTable]

问题出在Graphql 上：

 lazy val UserType: ObjectType[Unit, User] = deriveObjectType[Unit, User]()

当我尝试使用 derivedObjectType 宏创建 UserType 时，它​​抱怨说

找不到适合 .CommonFields 的 GraphQL 输出类型。如果您已经定义了它，请考虑使其隐含并确保它在范围内可用。

[错误] 惰性 val UserType: ObjectType[Unit, User] = derivedObjectType[Unit, User](

我如何告诉Sangria/Graphql如何处理这个嵌套的字段列表（来自 CommonFields）？

请帮忙。

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1 回答 1

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您正在为用户派生类型，但用户也有您尚未派生的 CommonFields。所以它无法找到 CommonFields 的类型信息。推导两者并使推导对 CommonFields 隐含。

implicit val CommonFieldsType: ObjectType[Unit, CommonFields] = deriveObjectType[Unit, CommonFields]     
implicit val UserType: ObjectType[Unit, User] = deriveObjectType[Unit, User]
于 2019-07-16T09:55:11.427 回答