Scala 处理slick dbio操作中的清理操作错误
我有下面的场景,我正在尝试使用巧妙的DBIO操作来实现它Scala 处理slick dbio操作中的清理操作错误,scala,exception-handling,slick,Scala,Exception Handling,Slick,我有下面的场景,我正在尝试使用巧妙的DBIO操作来实现它 Execute a batch Insert operation. On success, return the inserted result On failure, -> if the failure is due to duplicate value in a particular column, then remove the duplicates from the list, and try batch
Execute a batch Insert operation. On success, return the inserted result On failure,
-> if the failure is due to duplicate value in a particular column, then remove the duplicates from the list, and try batch insert again. If the second batch insert is successful, return a successful future with the second inserted list, else the failed future of the 2nd batch insert.
-> if the failure is due to something else, then throw that exception
对于上述场景,我尝试使用清理操作。但是,如果主操作失败,我不知道如何返回清理操作结果
如何使用DBIO操作错误处理来实现我的需求
def insertBatchAndReturnQuery(rowList: List[E]): FixedSqlAction[Seq[E], NoStream, Write] = {
query returning query ++= rowList
}
def insert(entities: List[E]): Future[Seq[E]] = {
val q = insertBatchAndReturnQuery(entities).cleanUp {
case Some(ex) => ex match {
case b: PSQLException => {
if (b.getSQLState.equals("23505")) {
//unique key exception, handle this by removing the duplicate entries from the list
???
} else {
throw new Exception("some database exception")
}
}
}
case None => insertBatchAndReturnQuery(Nil)
}
db.run(q)
}
这里的查询是TableQuery[T]
Slick版本:3.2.0-M2您可以从
清理
的签名中看到,它返回的操作的值与第一个操作的值类型相同,因此无法从清理操作返回值
如果希望返回第二个值,则需要使用asTry
将错误包装在Try
中,然后使用flatMap
。对于手头的问题,它看起来是这样的:
val q = insertBatchAndReturnQuery(entities).asTry.flatMap {
case Failure(b: PSQLException) if b.getSQLState == "23505" =>
//unique key exception, handle this
//by removing the duplicate entries from the list
???
case Failure(e) =>
throw new Exception("some database exception")
case Success(count) => DBIO.successful(count)
}
但是,文档警告说,使用asTry会丢失流媒体容量,因此您可能希望找到另一种方法来实现这一点。您可以从
清理
的签名中看到,它返回的操作值与第一个操作的值类型相同,因此,无法从清理操作返回值
如果希望返回第二个值,则需要使用asTry
将错误包装在Try
中,然后使用flatMap
。对于手头的问题,它看起来是这样的:
val q = insertBatchAndReturnQuery(entities).asTry.flatMap {
case Failure(b: PSQLException) if b.getSQLState == "23505" =>
//unique key exception, handle this
//by removing the duplicate entries from the list
???
case Failure(e) =>
throw new Exception("some database exception")
case Success(count) => DBIO.successful(count)
}
然而,文档警告说,使用asTry会丢失流媒体容量,因此您可能希望找到另一种方法来实现这一点