Question

I would like to know if there is some improvement on MongoCollection::findOne or if is just an “alias” or “shorcut” to MongoCollection::find with a limit of 1, for example.

Thank you

Answer 1

findOne() is an alias of find() with a limit(-1)

You can see this in the source code here. It does the equivalent to

find(...).limit(-1).getNext().

The -1 is actually relevant. Here’s a snippet from the wire protocol docs:

If the number is negative, then the database will return that number
and close the cursor.

If you go to the shell and type > db.collection.findOne (no parens), you can see that the function is also just a helper in the shell.

So, “yes findOne() is just a helper”.