Transactional SQL with Sails.js

Question

So I have been playing with NodeJS/Express for a little with now and I would really like to try to rewrite a relatively large side project using a full JavaScript stack just to see how it will work. Sails.js seems to be a pretty good choice for a NodeJS backend for a REST API with support for web sockets which is exactly what I am looking for however is one more issue I am looking to resolve and that is transactional SQL within NodeJS.

Most data layer/orms I have seen on the NodeJS side of things don't seem to support transactions when dealing with MySQL. The ORM provided with Sails.js (Waterline) also does not seem to support transactions which is weird because I have seen places where is mentioned it did though those comments are quite old. Knex.js has support for transactions so I was wondering if it is easy to replace the ORM is Sails.js with this (or if Sails.js assumes Waterline in the core framework).

I was also wondering if there is an ORM built on top of Knex.js besides Bookshelf as I am not a fan of Backbones Model/Collection system?

Answer 1

You can still write SQL queries directly using Model.query(). Since this is an asynchronous function, you'll have to use promises or async to reserialize it. For instance, using the MySQL adapter, async, and a model called User:

async.auto({
  transaction: function(next){
    User.query('BEGIN', next);
  },
  user: ['transaction', function(next) {
    User.findOne(req.param('id')).exec(next);
  }],
  // other queries in the transaction
  // ...
}, function(err, results) {
  if (err) {
    User.query('ROLLBACK', next);
    return next(err);
  }
  User.query('COMMIT', next);
  // final tasks
  res.json(results.serialize);
});

Answer 2

We're working on native support for transactions at the ORM level: https://github.com/balderdashy/waterline/issues/62

Associations will likely come first, but transactions are next. We just finished GROUP BY and aggregations (SUM, AVG, etc.)

Answer 3

Transactions in SailsJS turned out to be much trickier than anticipated. The goal is to let the ORM adapter know that two very disparate controller actions on models are to be sent through a single MySQL connection.

The natural way to do it is two write a new adapter that accepts an additional info to indicate that a query belongs to a transaction call. Doing that requires a change in waterline (sails ORM abstraction module) itself.

Checkout if this helps - https://www.npmjs.com/package/sails-mysql-transactions