Is this database design good? What JPA Entities should I create for this design?

Question

I am trying my hands on JPA. For this I am thinking of using the example of a student admission process as shown in the diagram below.

Is this design good ?

Any suggestions for improvement are more than welcome.

I am also confused about what Entity classes should I create for this. Especially for College_Major, should there be an Entity class for this or it should only be a mapping table created for many-to-many mapping between College and Major?

If the latter is a better case, how can the Admission_Form table refer to a Major in a College?

In either case, what should Entity classes (if good to have) for College_Major and Admission_Form look like?

Answer 1

Looks a fairly solid design apart from the college_major area which seems to be giving you problems as well :)

Personally, I would split this table into two:

1. Change the College_Major table to be a true many to many resolver (i.e. no intake int). This would become a reference table which is only changed when a college establishes a new major.
2. Intake, which links to College_Major and has the 1:* relationship to admission. I suspect that the intake date should be added, since it should not be possible to enrol a student for a non-existing course.

I like your use of id fields (aka business neutral primary keys). For consistency, the Student table primary key should probably be named student_id rather than just id.

You might like to give some thought to the name Admission_Form. It looks like the database is recording a successful admission, which may not always come from a form, and some forms may never result in an admission.

You will need a an entity class for each table except possibly College_Major. If I remember correctly, Hibernate can handle many to many relationship using collections (e.g College will have a list of majors, and major will have a list of colleges).