How the backend system of sign-in and login forms works?

Question

I just want to know how the sign in and login works if we talk about from backend. how data is stored in the database when someone makes a new account and how it confirmed that or retrieve the data from a database that user who is trying to login is a valid user.

I know how to use MySQL.

Answer 1

Hi Maninder here are the test cases for signin and login.
https://www.softwaretestingmaterial.com/test-scenarios-registration-form/
Also, simple login setup code:
https://www.tutorialrepublic.com/php-tutorial/php-mysql-login-system.php

Answer 2

I trying to explain in a simple way to you, if you using a backend like node.js, /post routes was used to upload data(remember upload is different to update data), and its often used to create users, and /get routes are used to consult data, then is used to login autentication.