gistfile1.js

var db = require('./exports-the-db-connection.js');
var http = require('http');

http.createServer(function(req, res){

	if (req.url == '/A')
		DoA();
	else if (req.url == '/B')
		DoB();
	else
		res.send("Fuck you!");

}).listen(80);

function DoA()
{
	db.query("BEGIN TRANSACTION", function(err, result){
		db.query("SELECT * FROM someTable", function(err, result){
			var importantInformation = results[0].someImportantColumn;

			if (importantInformation == 'somethingImportant')
			{
				db.query("INSERT someOtherTable (...) VALUES (...)", function(err, results){
					if (err)
					{
						db.query("ROLLBACK", function(){
							res.send("Aww...");
						});
					}
					else
					{
						db.query("COMMIT", function(){
							res.end("Yay!");
						})
					}
				});
			}
			else
			{
				res.end();
			}
		});
	});
}

function DoB(req, res)
{
	db.query("BEGIN TRANSACTION", function(err){
		db.query("UPDATE someTable SET someImportantColumn = 'somethingImporant'", function(){
			if (err)
			{
				db.query("ROLLBACK", function(){
					res.end('Something bad happened!');
				});
			}
			else
			{
				db.query("COMMIT", function(){
					res.end("Done did good!");
				})
			}
		});
	});
}