Isn’t supposed to be $set ????

I'm guessing you're on the question that asks:

The second parameter of the update method is the ___________ parameter.

The "update" method takes 3 parameters, which are: "query", "update", and "options". The correct answer is one of those.

Hi Mohammad

You somewhat right: we often use the $set operator for simple update operations, but inside the second parameter of update the $set operator is only one of many. Just to name a few:

• $currentDate (sets field to the current date)
• $inc (increments a field the specified number)
• $mul (multiplies a number by a given number)
• ...

All these operators and more can go into the update parameter (even multiple) like so:

db.cats.update({}, {$currentDate: {feededAt: true}, $inc: {age: 1}});