0

相关片段：

case class Video(
  id: String,
  title: String,
  url: String,
  pictureUrl: String,
  publishedAt: Date,
  channel: String,
  duration: Option[String],
  createdOn: Date
)

“连接”到数据库正在工作，从视频表中选择返回预期结果。我在保存时遇到问题，这个简单的方法：

  def saveToCache(item: Video): Unit = {
    logger.trace(item)
    import ctx._
    val x = quote {
      val lItem = lift(item)
      val fromDb = query[Video].filter(_.id == lItem.id)
      if (fromDb.isEmpty) query[Video].insert(lItem)
      else fromDb.update(lItem)
    }
    logger.trace(x.ast)
    run(x)
  }

在运行时崩溃（缩短）：

11:14:06.640 [scala-execution-context-global-84] ERROR io.udash.rpc.AtmosphereService - RPC request handling failed
org.sqlite.SQLiteException: [SQLITE_ERROR] SQL error or missing database (near "CASE": syntax error)
        at org.sqlite.core.DB.newSQLException(DB.java:909) ~[sqlite-jdbc-3.18.0.jar:na]
        at org.sqlite.core.DB.newSQLException(DB.java:921) ~[sqlite-jdbc-3.18.0.jar:na]
        at org.sqlite.core.DB.throwex(DB.java:886) ~[sqlite-jdbc-3.18.0.jar:na]
        at org.sqlite.core.NativeDB.prepare_utf8(Native Method) ~[sqlite-jdbc-3.18.0.jar:na]
        at org.sqlite.core.NativeDB.prepare(NativeDB.java:127) ~[sqlite-jdbc-3.18.0.jar:na]
        at org.sqlite.core.DB.prepare(DB.java:227) ~[sqlite-jdbc-3.18.0.jar:na]
        at org.sqlite.core.CorePreparedStatement.<init>(CorePreparedStatement.java:41) ~[sqlite-jdbc-3.18.0.jar:na]
        at org.sqlite.jdbc3.JDBC3PreparedStatement.<init>(JDBC3PreparedStatement.java:30) ~[sqlite-jdbc-3.18.0.jar:na]
        at org.sqlite.jdbc4.JDBC4PreparedStatement.<init>(JDBC4PreparedStatement.java:19) ~[sqlite-jdbc-3.18.0.jar:na]
        at org.sqlite.jdbc4.JDBC4Connection.prepareStatement(JDBC4Connection.java:48) ~[sqlite-jdbc-3.18.0.jar:na]
        at org.sqlite.jdbc3.JDBC3Connection.prepareStatement(JDBC3Connection.java:263) ~[sqlite-jdbc-3.18.0.jar:na]
        at org.sqlite.jdbc3.JDBC3Connection.prepareStatement(JDBC3Connection.java:235) ~[sqlite-jdbc-3.18.0.jar:na]
        at com.zaxxer.hikari.pool.ProxyConnection.prepareStatement(ProxyConnection.java:317) ~[HikariCP-2.7.2.jar:na]
        at com.zaxxer.hikari.pool.HikariProxyConnection.prepareStatement(HikariProxyConnection.java) ~[HikariCP-2.7.2.jar:na]
        at io.getquill.context.jdbc.JdbcContext.$anonfun$executeAction$1(JdbcContext.scala:98) ~[quill-jdbc_2.12-2.2.0.jar:2.2.0]
        at io.getquill.context.jdbc.JdbcContext.$anonfun$executeAction$1$adapted(JdbcContext.scala:97) ~[quill-jdbc_2.12-2.2.0.jar:2.2.0]
        at io.getquill.context.jdbc.JdbcContext.$anonfun$withConnection$1(JdbcContext.scala:46) ~[quill-jdbc_2.12-2.2.0.jar:2.2.0]
        at scala.Option.getOrElse(Option.scala:121) ~[scala-library-2.12.2.jar:1.0.0-M1]
        at io.getquill.context.jdbc.JdbcContext.withConnection(JdbcContext.scala:44) ~[quill-jdbc_2.12-2.2.0.jar:2.2.0]
        at io.getquill.context.jdbc.JdbcContext.executeAction(JdbcContext.scala:97) ~[quill-jdbc_2.12-2.2.0.jar:2.2.0]

编译期间宏的相关输出：

CASE WHEN NOT EXISTS (SELECT x3.* FROM video x3 WHERE x3.id = ?) THEN INSERT INTO video (id,title,url,picture_url,published_at,channel,duration,created_on) VALUES (?, ?, ?, ?, ?, ?, ?, ?) ELSE UPDATE video SET id = ?, title = ?, url = ?, picture_url = ?, published_at = ?, channel = ?, duration = ?, created_on = ? WHERE id = ? END

我想启用查询记录，但我不知道该怎么做（Quill 文档只说了一些关于 SLF4J 的信息，这对我来说是无用的信息 - 我没有看到任何日志，我不知道要搜索什么SLF4J 文档）。

到目前为止，我对 Quill 感到非常失望——它第一次在使用默认排序类型时生成了无效的排序查询，现在是这个。

4

1 回答 1

0

您应该将查询重写为：

import ctx._
def saveToCache(item: Video): Unit = {
  if (ctx.run(query[Video].filter(_.id == lift(item.id)).isEmpty))
    ctx.run(query[Video].insert(lift(item)))
  else ctx.run(query[Video].filter(_.id == lift(item.id)).update(lift(item)))
  ()
}

因为quote必须包含将被编译为单个查询的表达式。此代码将编译为三个查询。

但最好使用优化版本：

import ctx._
def saveToCacheOptimized(item: Video): Unit = {
  if (ctx.run(query[Video].filter(_.id == lift(item.id)).update(lift(item))) == 0)
    ctx.run(query[Video].insert(lift(item)))
  ()
}

编译为两个查询。

Quill 使用 SLF4J 进行日志记录，您应该阅读此项目文档。要启用日志记录，您应该添加一些日志记录后端，例如logback：

libraryDependencies ++= Seq(
  "ch.qos.logback" % "logback-classic" % "1.2.3"
)

仅记录查询就足够了。

于 2017-11-25T11:14:33.337 回答