What is the name of this architecture and what is the best way to implement it?

Question

OOP

Hello.
For interest, I decided to look at the list of things that I don’t have an answer for: I found a question that tormented me. The essence of the question:
how to write applications so that users can create their own data types (and tables in the database, etc.)? For example: there is a service where people register, and the administrator himself wants to add required fields (attributes) for each type of user (or even create new types of users himself). I think of it as dynamic classes, reflection and stuff. What is the name of such a thing, what is the best way to implement it? Enlighten me please.
Thank you.

Answer 1

A document-oriented database with a non-strict schema I think. NoSQL, MongoDB all things.

Answer 2

1. NoSql
2. postgresql json . There, you can even search inside json.
3. Create decorator tables and link them with Many - To - Many . In the link table, have type fields. Foreign keys will not work in this case.
Probably the most "not crutch" way is NoSQL.

Answer 3

this is where you can start