问题描述
我编写了一个简单的计数器，它使用 Anorm 更新 MySQL 数据库表.我希望事务是原子的.我认为最好的方法是将所有 SQL 字符串连接在一起并执行一个查询，但是 Anorm 似乎无法做到这一点.相反，我将每个选择、更新和提交放在不同的行上.这有效，但我不禁认为他们必须是更好的方法.
I have written a simple hit counter, that updates a MySQL database table using Anorm. I want the transaction to be atomic. I think that the best way would be to join all of the SQL strings together and do one query, but this doesn't seem to be possible with Anorm. Instead I have placed each select, update and commit on separate lines. This works but I can't help thinking that their must be a better way.
private def incrementHitCounter(urlName:String) {
DB.withConnection { implicit connection =>
SQL("start transaction;").executeUpdate()
SQL("select @hits:=hits from content_url_name where url_name={urlName};").on("urlName" -> urlName).apply()
SQL("update content_url_name set hits = @hits + 1 where url_name={urlName};").on("urlName" -> urlName).executeUpdate()
SQL("commit;").executeUpdate()
}
}
谁能找到更好的方法来做到这一点?
Can anyone see a better way to do this?
推荐答案
使用 withTransaction 而不是 withConnection 像这样:
Use withTransaction instead of withConnection like this:
private def incrementHitCounter(urlName:String) {
DB.withTransaction { implicit connection =>
SQL("select @hits:=hits from content_url_name where url_name={urlName};").on("urlName" -> urlName).apply()
SQL("update content_url_name set hits = @hits + 1 where url_name={urlName};").on("urlName" -> urlName).executeUpdate()
}
}
你为什么要在这里使用交易?这也应该有效:
And why would you even use a transaction here? This should work as well:
private def incrementHitCounter(urlName:String) {
DB.withConnection { implicit connection =>
SQL("update content_url_name set hits = (select hits from content_url_name where url_name={urlName}) + 1 where url_name={urlName};").on("urlName" -> urlName).executeUpdate()
}
}
这篇关于Anorm 中的原子 MySQL 事务的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持！