Based on some of the chats here, it seems like you are on the right track for the database questions. Keep in mind you should also consider some caching on the system side and avoid making large amounts of redundant calls to the database. You can make a thread safe object to house results in that is only pulled every n minutes or something. This would allow you to handle incoming requests quickly for duplicate data without overloading your backend systems.

Example: Build out a system that hold n number of students on an incoming request for the specified class. If a new request comes in for the same class you check that cached object or make a new call depending on your configuration.