scala - 使用 Squeryl 必须绑定(bind) session 错误

Question

更新:
好的，我解决了我遇到的问题，但我仍然不太确定我做错了什么。无论如何，我在 IRCDB 中编写了以下方法:

def tryit[T](p: => T) = {
    Class.forName("org.h2.Driver") //what's the point in this...?

    SessionFactory.concreteFactory = Some(() =>
        Session.create(java.sql.DriverManager.getConnection("jdbc:h2:~/irc","ScalaIRC",""), new H2Adapter))

    transaction {
        p
    }
}

然后像这样使用它:

 val query = from(IRCDB.channels)(c => select(c))
 IRCDB.tryit {
     for (r <- query) println("chan: " + r.name)
 }

现在它可以工作了。根据我的理解，我相信一旦使用 SessionFactory 创建 session ，我就可以使用 transaction { ... }任何有适当进口的地方。显然，我的理解是不正确的。

如果有人有什么要补充的，请做。

所以，我刚开始将 Squeryl 用于我正在从事的项目，所以这可能只是我的疏忽。所以，首先是代码:

我有以下进口:

import org.squeryl.PrimitiveTypeMode._
import java.sql.Timestamp
import java.sql.DriverManager
import java.util.Date
import org.squeryl.adapters.H2Adapter
import org.squeryl.dsl.{OneToMany, ManyToOne, CompositeKey2}
import org.squeryl._

我定义了下表:

class ChannelTable(val id: Long, val name : String,
               val p_mode : Boolean, val s_mode : Boolean,
               val i_mode : Boolean, val t_mode : Boolean,
               val n_mode : Boolean, val m_mode : Boolean,
               val key : Option[String]) extends KeyedEntity[Long] {
    def this() = this(0,"", false, false, false, false, false, false, Some(""))

    lazy val bans:OneToMany[ChannelBanTable] = IRCDB.channelToChanBans.left(this)
    lazy val users = IRCDB.channelUsers.left(this)
    lazy val invites = IRCDB.channelInvites.left(this)
}

并定义了以下架构:

object IRCDB extends Schema {
    val channels = table[ChannelTable]

    on(channels)(c => declare(
      c.p_mode defaultsTo(false),
      c.s_mode defaultsTo(false),
      c.i_mode defaultsTo(false),
      c.t_mode defaultsTo(false),
      c.n_mode defaultsTo(false),
      c.m_mode defaultsTo(false),
      c.name is(unique, indexed)
    ))

    def init {
        Class.forName("org.h2.Driver") //what's the point in this...?

        SessionFactory.concreteFactory = Some(() =>
          Session.create(DriverManager.getConnection("jdbc:h2:~/irc","ScalaIRC",""), new H2Adapter))
    }
    def getAllChannels = transaction { from(channels)(c => select(c))}
}

我已经能够在控制台中使用以下内容插入表中:

scala> import db._;import org.squeryl.PrimitiveTypeMode._
import db._
import org.squeryl.PrimitiveTypeMode._
scala> IRCDB.init
scala> transaction { IRCDB.channels.insert(new ChannelTable(0,"#chan_name", false, false, false, false, false, false, None)) }
res3: db.ChannelTable = db.ChannelTable@4

我可以通过 H2 控制台确认这确实发生了。但是，当我调用 IRCDB.getAllChannels (在 Scala 控制台和代码中)我收到以下错误:

java.lang.RuntimeException: no session is bound to current thread, a session must be created via Session.create 
and bound to the thread via 'work' or 'bindToCurrentThread'
    at scala.Predef$.error(Predef.scala:58)
    at org.squeryl.Session$$anonfun$currentSession$1.apply(Session.scala:117)
    at org.squeryl.Session$$anonfun$currentSession$1.apply(Session.scala:117)
    at scala.Option.getOrElse(Option.scala:59)
    at org.squeryl.Session$.currentSession(Session.scala:116)
    at org.squeryl.dsl.AbstractQuery.org$squeryl$dsl$AbstractQuery$$_dbAdapter(AbstractQuery.scala:136)
    at org.squeryl.dsl.AbstractQuery$$anon$1.<init>(AbstractQuery.scala:140)
    at org.squeryl.dsl.AbstractQuery.iterator(AbstractQuery.scala:138)
    at scala.collection.IterableLike$class.foreach(IterableLike.scala:79)
    at org.squeryl.dsl.AbstractQuery.foreach(AbstractQuery.scala:27)
    at scala.collection.TraversableLike$class.map(TraversableLike.scala:206)
    at org.squeryl.dsl.AbstractQuery.map(AbstractQuery.scala:27)
    at scala.runtime.ScalaRunTime$.inner$1(ScalaRunTime.scala:255)
    at scala.runtime.ScalaRunTime$.stringOf(ScalaRunTime.scala:258)
    at RequestResult$line7$object$.<init>(<console>:12)
    at RequestResult$line7$object$.<clinit>(<console>)
    at RequestResult$line7$object.scala_repl_result(<console>)
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
    at java.lang.reflect.Method.invoke(Method.java:597)
    at scala.tools.nsc.Interpreter$Request$$anonfun$loadAndRun$1$$anonfun$apply$18.apply(Interpreter.scala:981)
    at scala.tools.nsc.Interpreter$Request$$anonfun$loadAndRun$1$$anonfun$apply$18.apply(Interpreter.scala:981)
    at scala.util.control.Exception$Catch.apply(Exception.scala:79)
    at scala.tools.nsc.Interpreter$Request$$anonfun$loadAndRun$1.apply(Interpreter.scala:980)
    at scala.tools.nsc.Interpreter$Request$$anonfun$loadAndRun$1.apply(Interpreter.scala:980)
    at scala.util.control.Exception$Catch.apply(Exception.scala:79)
    at scala.tools.nsc.Interpreter$Request.loadAndRun(Interpreter.scala:979)
    at scala.tools.nsc.Interpreter.loadAndRunReq$1(Interpreter.scala:578)
    at scala.tools.nsc.Interpreter.interpret(Interpreter.scala:597)
    at scala.tools.nsc.Interpreter.interpret(Interpreter.scala:575)
    at scala.tools.nsc.InterpreterLoop.reallyInterpret$1(InterpreterLoop.scala:471)
    at scala.tools.nsc.InterpreterLoop.interpretStartingWith(InterpreterLoop.scala:514)
    at scala.tools.nsc.InterpreterLoop.command(InterpreterLoop.scala:361)
    at scala.tools.nsc.InterpreterLoop.processLine$1(InterpreterLoop.scala:242)
    at scala.tools.nsc.InterpreterLoop.repl(InterpreterLoop.scala:248)
    at scala.tools.nsc.InterpreterLoop.main(InterpreterLoop.scala:558)
    at scala.tools.nsc.InterpreterLoop.main(InterpreterLoop.scala:609)
    at org.jetbrains.plugins.scala.compiler.rt.ConsoleRunner.main(ConsoleRunner.java:33)
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
    at java.lang.reflect.Method.invoke(Method.java:597)
    at com.intellij.rt.execution.application.AppMain.main(AppMain.java:115)

如果我能够以几乎相同的方式将行插入表中，我不明白为什么会出现此错误。如果我尝试执行 transaction { from(IRCDB.channels)(c => select(c)) }在控制台我得到同样的错误。

编辑:我添加了完整的堆栈跟踪。另外，我重写了 getAllChannels像这样的功能:

def getAllChannels = transaction { 
  val ret = from(channels)(c => select(c))
  println("sql: " + ret)
  ret
}

我仍然收到一个错误，但它确实先打印出查询——我认为这可能有用:

sql: 'QueryExpressionNode[root:1a0d111]:rsm='ResultSetMapper:fdf48d()--
    'FieldSelectElement:ChannelTable1_name
        org.squeryl.dsl.ast.FieldSelectElement$$anon$3
    'FieldSelectElement:ChannelTable1_i_mode
        org.squeryl.dsl.ast.FieldSelectElement$$anon$3
    'FieldSelectElement:ChannelTable1_s_mode
        org.squeryl.dsl.ast.FieldSelectElement$$anon$3
    'FieldSelectElement:ChannelTable1_key
        org.squeryl.dsl.ast.FieldSelectElement$$anon$3
    'FieldSelectElement:ChannelTable1_n_mode
        org.squeryl.dsl.ast.FieldSelectElement$$anon$3
    'FieldSelectElement:ChannelTable1_m_mode
        org.squeryl.dsl.ast.FieldSelectElement$$anon$3
    'FieldSelectElement:ChannelTable1_id
        org.squeryl.dsl.ast.FieldSelectElement$$anon$3
    'FieldSelectElement:ChannelTable1_t_mode
        org.squeryl.dsl.ast.FieldSelectElement$$anon$3
    'FieldSelectElement:ChannelTable1_p_mode
        org.squeryl.dsl.ast.FieldSelectElement$$anon$3
    'ViewExpressionNode[sample:ChannelTable[16e3f87]]:rsm='ResultSetMapper:442b95($(1->ChannelTable.name:java.lang.String),$(2->ChannelTable.i_mode:java.lang.Boolean),$(3->ChannelTable.s_mode:java.lang.Boolean),$(4->ChannelTable.key:Option[java.lang.String]),$(5->ChannelTable.n_mode:java.lang.Boolean),$(6->ChannelTable.m_mode:java.lang.Boolean),$(7->ChannelTable.id:java.lang.Long),$(8->ChannelTable.t_mode:java.lang.Boolean),$(9->ChannelTable.p_mode:java.lang.Boolean))--*

Select
  ChannelTable1.name as ChannelTable1_name,
  ChannelTable1.i_mode as ChannelTable1_i_mode,
  ChannelTable1.s_mode as ChannelTable1_s_mode,
  ChannelTable1.key as ChannelTable1_key,
  ChannelTable1.n_mode as ChannelTable1_n_mode,
  ChannelTable1.m_mode as ChannelTable1_m_mode,
  ChannelTable1.id as ChannelTable1_id,
  ChannelTable1.t_mode as ChannelTable1_t_mode,
  ChannelTable1.p_mode as ChannelTable1_p_mode
From
  ChannelTable ChannelTable1
java.lang.RuntimeException: no session is bound to current thread, a session must be created via Session.create 
and bound to the thread via 'work' or 'bindToCurrentThread'
    at scala.Predef$.error(Predef.scala:58)
    at org.squeryl.Session$$anonfun$currentSession$1.apply(Session.scala:117)
    at org.squeryl.Session$$anonfun$currentSession$1.apply(Session.scala:117)
    at scala.Option.getOrElse(Option.scala:59)
    at org.squeryl.Session$.currentSession(Session.scala:116)
    at org.squeryl.dsl.AbstractQuery.org$squeryl$dsl$AbstractQuery$$_dbAdapter(AbstractQuery.scala:136)
    at org.squeryl.dsl.AbstractQuery$$anon$1.<init>(AbstractQuery.scala:140)
    at org.squeryl.dsl.AbstractQuery.iterator(AbstractQuery.scala:138)
    at scala.collection.IterableLike$class.foreach(IterableLike.scala:79)
    at org.squeryl....

Answer 1

这是我怀疑的，你的方法:
def getAllChannels = transaction { from(channels)(c => select(c))}
正在返回 未评估 查询，即
返回类型
from(channels)(c => select(c))
是 Query[ChannelTable]所以方法返回，事务结束，控制台尝试打印它，
触发评估:

at org.squeryl.dsl.AbstractQuery.map(AbstractQuery.scala:27)        
at scala.runtime.ScalaRunTime$.inner$1(ScalaRunTime.scala:255)
at scala.runtime.ScalaRunTime$.stringOf(ScalaRunTime.scala:258)
at RequestResult$line7$object$.<init>(<console>:12)
at RequestResult$line7$object$.<clinit>(<console>)
at RequestResult$line7$object.scala_repl_result(<console>)

由于交易结束，您会收到您收到的消息。

试试这个 :

def getAllChannels = transaction { 
  val q = from(channels)(c => select(c))
  for(z <- q) {
    println(z)
  }
}