How to use nextcloud user_backend_sql_raw replace enbed user managment

I want to use nextcloud user_backend_sql_raw instead of embed user management. Can this be done?
The users which I expect the android/ios app or web management page has added are added to user_backend_sql_raw,and there is no need for modification android/ios app.

I am not sure what you mean, but why shouldn’t you be able to use it?

I want to register users to an external database or external modules via a nextcloud management page or a mobile APP, with no need to modify the core code of the nextcloud as well as the web page or mobile APP code

Yes, that should work with this plug-in (app). Of course, I don’t know the details of your db, but this is what the plug-in is for.

thanks ,My idea is to achieve this by nextcloud user_backend_sql_raw, wondering if I can achieve my purpose

I understand that both web pages and mobile apps call OCP \ IUserManager, while nextcloud user_backend_sql_raw is an implementation of OCP \ IUserManager. Through the dependent injection mechanism, web pages and mobile APP actually eventually call user_backend_sql_raw. Do I understand it correctly?