What could be used to create a system of "controlling access of employees to the premises"?

Question

Physical access control

Foolishly, I took this topic for surrender: " create a system for accessing employees to the premises of the enterprise ", which theoretically should open doors or turnstiles, driving everything into the fact that you can simply simply make a beautiful database, which theoretically should send a signal to some device, first by checking the access key in this very database.
But, in practice, this has never been done. The enterprise was quarantined, so my only help evaporated indefinitely. In general, I just want to get an answer (preferably detailed) to such a short question: What are such systems generally made on? ..I'm already thinking of reducing this task to an "abstract" control system, which in THEORY could open turnstiles .. But I'm not even a bunbun. I have some "experience" in C# development. Worked on the web with MariaDB and similar via PHP. True, I think this experience is zero for this work.

Answer 1

https://securityrussia.com/blog/setevye-skud.html

Answer 2

We open our favorite search engine and drive in "SKUD" - there you will find goals and objectives, structural diagrams and composition

Answer 3

We made such a system (videolink.ru company) on an interesting CAN network. The controllers were made by an electronics engineer (now retired). Database on the server. The client interface is standard. The necessary data is loaded into the controllers for offline operation. There is even such a trick: a person can enter through one door and exit through another. One person can't do everything.