Why are documents not being embedded in Mongo?

Question

MongoDB

Good afternoon. Went into a dead end. Google didn't help.
There are 2 models in mongoose - Project, Payment. One-to-many relationship. There are many Payments in one Project.

Here is the Payment model, which has a reference to the creator - the Project model.

I want to get all Projects with Pyments embedded in them via populate();

But instead comes an empty array.

When creating a Payment, I save them like this with a link to the Project

What am I doing wrong?
By the way, if you put _ before payments in the Project model, then not an empty payments array is returned, but with payments id's.

Answer 1

And where is the description of the Payment model?

Answer 2

Already decided. When adding a new record to Payment, it was necessary not only to set the owner of the Project model to it, but also to push a new Payment to the Project.