model management in MVC

I finding a best practice for doing model in MVC. I'm doing a socket server with concurrent users. As I understand model in MVC have included business logic that be 1) if I get a model from a data access or maybe db SAO. How can this model object be updated when someone else has changed an attribute in DB ?

I think first solution is always get an attribute of model by access from database second is make a model pool and modify the reference. Apologize if I misunderstand some basic thing. Any suggestion?