Knowing how to structure hierarchy, within data, should be one of your core pieces of know-how regarding data structure. Once you understand it, you can always leverage the knowledge for a variety of tasks. This structure applies to checking for sequential numerical entries (knowing when sequence is broken), generating a visual tree of levels and sub levels or storing a list of hierarchical value lists - most efficiently.
Building on a file presented in 2004, it goes to show that this basic structure for how data is stored does not change, nor is it likely to ever change. It's simply how you store data for hierarchy based information.
If, in your database, you need to present value list selections that hinge on each other then this is the video and technique file that you need!