Let’s Build a Simple Database (2017)
I have spent quite a lot of time building a database in Java. It's not a small undertaking.I've gone through as many books and papers as I can, and there is only one, one, that gives an overview and actual examples of building a system that processes SQL. Everything else is theoretical or so general that you don't get enough direction to get started.It's "Database Design and Implementation" by Sciore. It's a little dated, but not by much. It is an underappreciated resource.