Any database primer e.g. intro-level textbook would do, for the basics of relational integrity. But try finding a developer these days who has read a book or s

Any database primer e.g. intro-level textbook would do, for the basics of relational integrity. But try finding a developer these days who has read a book or shows any interest whatsoever in writing SQL. Most of them just want to work with it behind an abstraction layer.