It takes me back to my school years. I never got as far as you (not by any long stretch actually), but I did enjoy creating the storage layer of a database from scratch. To actually have to deal with, instead of just think of, all the edge cases, is quite the transformative experience.
As a humble suggestion, since it seems your goal is to understand how relational databases work and not necessarily to write a new database that will compete with others, maybe don't make it an SQL one? We've got enough of those, and not enough of the others. Would be nice to have a new relational DB using Tutorial D as its language for example.
It takes me back to my school years. I never got as far as you (not by any long stretch actually), but I did enjoy creating the storage layer of a database from scratch. To actually have to deal with, instead of just think of, all the edge cases, is quite the transformative experience.
As a humble suggestion, since it seems your goal is to understand how relational databases work and not necessarily to write a new database that will compete with others, maybe don't make it an SQL one? We've got enough of those, and not enough of the others. Would be nice to have a new relational DB using Tutorial D as its language for example.
Keep hacking!