Let's be clear about our language here:
DBMS = database management system = a generic engine with which one can manage many different collections of data for different purposes (each of those being called a database).
DB = database = a specific instance of a collection of data for a specific purpose, using a DBMS.
So, which of these are you building? If you want to build a truly relational
database management system, my hat is off to you. I think, however, that you will find this is a large job that cannot be accomplished by any one person in a reasonable time. In fact, none of the larger SQL DBMS vendors has truly accomplished this task. Oracle, the largest of these, manages only about 60% compliance with the logical features of a true relational DBMS, according to Codd & Date. (We have had a few
discussions about this in the past).
I would also suggest that VB is not the tool to use for this. However, if you simply mean you want to develop a VB application that manages a few flat lists of items, you could perhaps accomplish this by using CSV files (the "flat file" database approach). Don't expect this to remotely resemble a true relational DBMS, though.