创建通用的更新计数器方法 [英] Creating a generic update counter method

问题描述

我正在尝试为特定表创建通用计数器更新方法.

我的表中有许多列只是计数器，在我的应用程序中，我需要增加/减少这些计数器.

我正在尝试创建这样的方法:

private def updateCounter(column: String, id: Int, incr: Int)(implicit session: Session): Unit = {
  sqlu"update table1 set $column = $column + $incr where id=$id".first
}

然后我将创建一个调用此方法的方法(我不想将此方法公开到此Dao类之外).

我收到此错误:

[PSQLException: ERROR: syntax error at or near "$1" Position: 20]

解决方案

尝试将$column替换为#$column. $用于绑定变量，它不是适用于列或表名称之类的标识符，而 #$只是像s""字符串插值这样的字符串替换.

还要确保您的列变量不容易受到SQL注入的攻击.<​​/p>

I'm trying to create a generic counter update method for a particular table.

My table has many columns that are simply counters, and in my application I need to increment/decrement these counters.

I was trying to create a method like this:

private def updateCounter(column: String, id: Int, incr: Int)(implicit session: Session): Unit = {
  sqlu"update table1 set $column = $column + $incr where id=$id".first
}

I would then create a method that would call this (I don't want to expose this method outside of this Dao class).

I am getting this error:

[PSQLException: ERROR: syntax error at or near "$1" Position: 20]

解决方案

Try replacing $column by #$column. $ is used for bind variables which is not suitable for identifiers like column or table names, whereas #$ is a mere string replacement like the s"" string interpolation.

Also make sure that your column variable is not vulnerable to SQL injections.

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