[SlickException:读取列的NULL值(USERS /670412212).LOGIN_ID]

Question

我正在使用Slick 1.0.0和play framework 2.1.0.当我查询我的Users表时,我收到以下错误.LOGIN_IDDB中的值为null.我正在执行的查询是:

    val user = { for { u <- Users if u.providerId === id.id } yield u}.first

这会导致以下错误:

play.api.Application$$anon$1: Execution exception[[SlickException: Read NULL value for column (USERS /670412212).LOGIN_ID]]
    at play.api.Application$class.handleError(Application.scala:289) ~[play_2.10.jar:2.1.0]
    at play.api.DefaultApplication.handleError(Application.scala:383) [play_2.10.jar:2.1.0]
    at play.core.server.netty.PlayDefaultUpstreamHandler$$anonfun$12$$anonfun$apply$24.apply(PlayDefaultUpstreamHandler.scala:314) [play_2.10.jar:2.1.0]
    at play.core.server.netty.PlayDefaultUpstreamHandler$$anonfun$12$$anonfun$apply$24.apply(PlayDefaultUpstreamHandler.scala:312) [play_2.10.jar:2.1.0]
    at play.api.libs.concurrent.PlayPromise$$anonfun$extend1$1.apply(Promise.scala:113) [play_2.10.jar:2.1.0]
    at play.api.libs.concurrent.PlayPromise$$anonfun$extend1$1.apply(Promise.scala:113) [play_2.10.jar:2.1.0]
scala.slick.SlickException: Read NULL value for column (USERS /670412212).LOGIN_ID
    at scala.slick.lifted.Column$$anonfun$getResult$1.apply(ColumnBase.scala:29) ~[slick_2.10-1.0.0.jar:1.0.0]
    at scala.slick.lifted.TypeMapperDelegate$class.nextValueOrElse(TypeMapper.scala:158) ~[slick_2.10-1.0.0.jar:1.0.0]
    at scala.slick.driver.BasicTypeMapperDelegatesComponent$TypeMapperDelegates$StringTypeMapperDelegate.nextValueOrElse(BasicTypeMapperDelegatesComponent.scala:146) ~[slick_2.10-1.0.0.jar:1.0.0]
    at scala.slick.lifted.Column.getResult(ColumnBase.scala:28) ~[slick_2.10-1.0.0.jar:1.0.0]
    at scala.slick.lifted.Projection15.getResult(Projection.scala:627) ~[slick_2.10-1.0.0.jar:1.0.0]
    at scala.slick.lifted.Projection15.getResult(Projection.scala:604) ~[slick_2.10-1.0.0.jar:1.0.0]

我的用户表定义为:

package models

import scala.slick.driver.MySQLDriver.simple._

case class User(userId:String,email:String,loginId:String,fullName:String,firstName:String,lastName:String,location:String,homeTown:String,providerId:String,provider:String,state:String,zip:String,accessKey:String,refreshKey:String,avatarUrl:String)

object Users extends Table[User]("USERS") {
  def userId = column[String]("USER_ID", O.PrimaryKey) // This is the primary key column
  def email =  column[String]("EMAIL",O.NotNull)
  def loginId = column[String]("LOGIN_ID",O.Nullable)
  def fullName = column[String]("FULL_NAME",O.NotNull)
  def firstName = column[String]("FIRST_NAME",O.Nullable)
  def lastName = column[String]("LAST_NAME",O.Nullable)
  def location = column[String]("LOCATION",O.Nullable)
  def homeTown = column[String]("HOME_TOWN",O.Nullable)
  def providerId = column[String]("PROVIDER_ID",O.Nullable)
  def provider = column[String]("PROVIDER",O.Nullable)
  def state = column[String]("STATE",O.Nullable)
  def zip = column[String]("ZIP",O.Nullable)
  def accessKey = column[String]("ACCESS_KEY",O.Nullable)
  def refreshKey = column[String]("REFRESH_KEY",O.Nullable)
  def avatarUrl = column[String]("AVATAR_URL",O.Nullable)

  // Every table needs a * projection with the same type as the table's type parameter
  def * = userId ~ email ~ loginId ~ fullName ~ firstName ~ lastName ~ location ~ homeTown ~ providerId ~ provider ~ state ~ zip ~ accessKey ~ refreshKey ~ avatarUrl <> (User,User.unapply _)
}

请帮忙.看起来Slick无法处理来自DB的Null值？

Answer 1

你的案例类不合适.如果您使用O.Nullable,您的所有财产都必须是 Option[String].

Answer 2

如果出现此错误，则必须设置属性O.Nullable，或者必须指定查询返回一个选项。

例如，假设您执行了一个操作rightJoin，则可能不想将正确记录的属性设置为可选。在这种情况下，您可以使用以下方法自定义产生结果的方式.?

val results = (for {
  (left, right) <- rightRecord.table rightJoin leftRecord.table on (_.xId === _.id)
  } yield (rightRecord.id, leftRecord.name.?)).list
results map (r => SomeJoinedRecord(Some(r._1), r._2.getOrElse(default)))