I'm adding a table and subclass table to my DB. (Subclass table = table where the primary key joins to the primary key of another table, to give extra row information to some subset of the rows ...

Foreign keys enforce table relationships, for example (in the case of school enrollments) forbidding you from adding a non-existent student to a class roster, or from deleting a class roster that ...

For everyone normalizing their designs, just remember: There ain't no such thing as a partial foreign key. When a project pretends that partial foreign keys are a valid concept, the end result is a ...