[miguendes]

The best book I've ever found so far is this one: https://www.springer.com/gp/book/9783030338350

The author builds a small relational database from scratch in java. It supports only a few types and not all SQL commands but it's great to get a big picture.

[debo_]

Thank you for this! I've never heard of it before, and it seems like precisely what I was looking for.