Also, db.multi can be very handy if you need to make several requests at the same time. It will then act as a transactional mode:

db.multi([
["set", "status", "good"],
["hmset", "user", {name: "Jonh", age: 30}],
]).exec(function (err, replies) {
if(!err){
…
} else {
…
}
});

Luc