如何處理交易錯誤？

Question

想象我有一個HTTP請求處理機內部以下代碼：

// these come from the HTTP request payload. 
var channel = {}; 
var screencast ={}; 

try { 
    connection.beginTransaction(function(err) { 
    if (err) { 
     throw err; 
    } 
    connection.query('INSERT INTO Channels SET ?', channel, function (err, result) { 
     if (err) { 
     connection.rollback(function() { 
      throw err; 
     }); 
     }