JSF :: How To Update Datatable After Registering User In Database

I have requirement, in that I am showing a Datatable, above that table i have form in that i can register a employee, after clicking on submit employee data have to be saved in the database aswell as i have to update datable, so that I can see that registered employee in that Datatable, how can i full fill this requirement. I am using jsf 2.0, ejb3.0,jpa 2.0.

@Override
public List<Employees> getallEmployees() {
System.out.println("all employee fetched");
return (List<Employees>) em.createNamedQuery("Employees.findAll").getResultList();
}

In managed bean I am calling this service as fallow in init method, and i am binding same this. employee list to UI

public String getAllEmployeesfronHr() {
this.employees = customerservice.getallEmployees();
System.out.println(this.employees.size() + "=================size of employee");
return "";
}

For every submit button click i have to query database or is there any mechanism to update List / can we use entity manager in anyway so that we can update Employee List....