For Higher Computing Science, revise the use of primary and foreign keys and the difference between flat file and relational databases.

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 ...

A foreign key integrity constraint links the data values of one or more variables in its data file to those of the variables specified in a primary key, and controls the action that can be taken when ...