Why is save() recommended over update methods?

[vresetnikov]

Hello,

The mongoose documentation states:

So mongoose says:

_You should use save() rather than updateOne() and updateMany() where possible. However, Model.updateOne() and Model.updateMany() have a few advantages:

updateOne() is atomic. If you load a document using find(), it may change before you save() it.
updateOne() doesn't require you to load the document into memory, which may give you better performance if your documents are huge._

The docs don't explain why it is recommended to use save() instead of those other methods. Furthermore, the 2 advantages indicated seem to be sufficient to do the opposite - opt for those other methods as they are potentially safer and more performant. So what would be the main reasons for the save() recommendation?

[vkarpov15]

We'll add a little more info on that. Because you have the document in memory, save() gives you more complete validation (updateOne() can't validate inc, etc.) and better middleware support. So save() gives you access to more features, but updateOne() is faster and atomic.

[hembhagat99]

@vkarpov15 I think updateOne and updateMany should be recommended in the documentation since faster and atomic are requirements of almost all real-world applications. So, why recommend save?

Also, can you elaborate (or point me to documentation) why having validators on updateOne and updateMany is problematic?

[vkarpov15]

@hembhagat99 because updateOne() being atomic means that the document being updated isn't in Node.js, so Mongoose can't run validation logic on the document.

" since faster and atomic are requirements of almost all real-world applications." <-- false. Fast enough is a requirement, and atomic is nice to have in most cases, especially if you turn on OCC. But up to you, if save() is too slow then you can always use updateOne().