Slick 不知道如何映射给定的类型

Question

下面是我的代码

package com.codemobile.box.modules.groups.repo.sql
import com.codemobile.box.core.services.DatabaseService
import com.codemobile.box.modules.groups.model.GroupEntity
trait GroupEntityTable {
  protected val databaseService: DatabaseService
  import databaseService.driver.api._
  class Groups(tag: Tag) extends Table[GroupEntity](tag, "groups"){
    val id = column[Int]("grp_id",O.PrimaryKey,O.AutoInc)
    val name = column[String]("grp_name")
    val permissions = column[String]("grp_permissions")
    def * = (id, name, permissions) <> (GroupEntity.tupled, GroupEntity.unapply)
  }

  protected val groupsTableQuery = TableQuery[Groups]

}


package com.codemobile.box.modules.groups.model
case class GroupEntity(id: Option[Int] = None, name: String, permissions : Option[String] = None)

但是当我 运行 激活器 运行 我得到低于异常

[error] Slick does not know how to map the given types.
[error] Possible causes: T in Table[T] does not match your * projection. Or you use an unsupported type in a Query (e.g. scala List).
[error]   Required level: slick.lifted.FlatShapeLevel
[error]      Source type: (slick.lifted.Rep[String], slick.lifted.Rep[String], slick.lifted.Rep[Option[Int]])
[error]    Unpacked type: (Option[Int], String, Option[String])
[error]      Packed type: Any
[error]     def * = (name, permissions, id.?) <> (GroupEntity.tupled, GroupEntity.unapply)
[error]                                       ^
[error] one error found

Answer 1

只需将 Option 添加到映射中的类型：

  class Groups(tag: Tag) extends Table[GroupEntity](tag, "groups"){
    val id = column[Option[Int]]("grp_id",O.PrimaryKey,O.AutoInc)
    val name = column[String]("grp_name")
    val permissions = column[Option[String]]("grp_permissions")
    def * = (id, name, permissions) <> (GroupEntity.tupled, GroupEntity.unapply)
  }

（注意我如何将 column 更改为 id 和 permissions）

或者您可以这样做：

  class Groups(tag: Tag) extends Table[GroupEntity](tag, "groups"){
    val id = column[Int]("grp_id",O.PrimaryKey,O.AutoInc)
    val name = column[String]("grp_name")
    val permissions = column[String]("grp_permissions")
    def * = (id.?, name, permissions.?) <> (GroupEntity.tupled, GroupEntity.unapply)
  }

（注意我如何更改 * 投影并在 id 和 permissions 之后添加 ?）