How to model government organization hierarchies so that the list can expand and compress

[Ian Kelly]

On Thu, Aug 13, 2015 at 1:10 PM, Alex Glaros <alexglaros at gmail.com> wrote:
> It's like the desktop folder/directory model where you can create unlimited folders and put folders within other folders. Instead of folders, I want to use government organizations.
>
> Example: Let user create agency names: Air Force, Marines, Navy, Army. Then let them create an umbrella collection called "Pentagon", and let users drag Air Force, Marines, Navy, etc. into the umbrella collection.
>
> User may wish to add smaller sub-sets of Army, such as "Army Jeep Repair Services"
>
> User may also want to add a new collection "Office of the President" and put OMB and Pentagon under that as equals.
>
> What would the data model look like for this?  If I have a field: next_higher_level_parent that lets children records keep track of parent record, it's hard for me to imagine anything but an inefficient bubble sort to produce a hierarchical organizational list. Am using Postgres, not graph database.
>
> I'm hoping someone else has worked on this problem, probably not with government agency names, but perhaps the same principle with other objects.

https://en.wikipedia.org/wiki/Tree_(data_structure)