The purpose of this project is to demonstrate a relation DB setup within Firebase. You can think of the Firebase branches as analogous to tables in a traditional relational database. I've used StudentID as the link between tables, similar to the use of a primary and foreign key. No styling has been added to this demonstration (obviously!) to keep the focus on the implementation of the database.
The demonstration consists of two branches, the StudentBook and the GradeBook. The common 'key' field is the Student ID which is used in the View Grades page when it searchs for a Last Name in the student branch and matches it to the appropriate grades in the Grade Branch using the 'Student ID'.
Please note that this demonstration is not functionally complete - it doesn't verify if an existing student ID already exists, etc. When testing this demonstration take care to enter matching StudentIDs when entering student details and their grade details.
Screenshot from the database showing the branches and sample data. Notice the common primary/foreign key of StudentID