Node.js + MySQL - handling transactions

Question

I am building an app on node.js using express, and node-mysql driver. There is a couple of cases in my app when I need to make a series of database inserts/updates. I want them

Answer 1

I find it hard to believe that if a separate session executes a START TRANSACTION that other transactions are committed. That would be totally unsafe, especially when data needs to be rollbacked (or is it "rolled back"?).

Is it possible you're mixing this up with a same session START TRANSACTION?
See http://dev.mysql.com/doc/refman/5.0/en/implicit-commit.html where it explains that transactions cannot be nested. That of course applies to the same session, not to another user's session.

Assuming you haven't messed around with the isolation level of your session, or the global isolation level, then transactions should be safe.

In any case, if you wanted to queue your transactions it wouldn't be hard to build a global queue object in node and chain the calls (so one starts when another finishes). A simple array with push and pop should do the trick.