Which scheme is better to choose for storing arbitrary data?

Question

Database

Hello.
I am making a web application in which users can upload csv files of any format and work with them. I thought about how to store such data and what would be better in this case, Postgres or MongoDB?
So far, there are 2 options in my head: store each such document as a separate table / collection and keep the link user-> collections
or create one common storage for everything (MongoDB will be more convenient here).
I didn’t do anything like that, and then I don’t really want to redo the schema and migrate a bunch of data;

Answer 1

from the text of the question we can see that:
csv: this is a table with an arbitrary number of fields and untyped data.
It is better to store as a collection unambiguously.

Answer 2

I am not a master in this matter, but I think it will be OK to use "key" and "value" here.

ключ = id
значение = данные в JSON формате

It's kind of a one-size-fits-all solution :)