如何使用java在mongoDB中创建一对多

So I'm trying to make a system that is one of many styles DB in mongo using java.I am trying to recreate a school grading database where there are: teachers, classes, periods, students and their grades attributes. But my question is how do I implement one to many in java, for example, teachers and the classes they teach. So I'm trying to make a system that is one of m