This is the lesser known of the *DD approaches for design and development.  Essentially, all logic lives within your stored procedures (sprocs) within your database.  And by "all logic", I mean, ALL LOGIC.

That's right, ALL validation, business rules, persistence, workflow, etc. resides within sprocs that interact against your database.

What makes it challenging is when you try to implement some object oriented techniques with a strictly procedural language.  That's what I call, "exercising your tech-muscle."