Yeah, sort of. I probably didn't explain super well, and also probably don't fully understand the problem so here are some code snippets that might make things more concrete and you can tell me where my asumptions of your codebase are wrong
So first off we have what I assume you were suggesting with multiple options for the individual db props. I commented where things are painful and bug prone:
If Option is indeed the aproach you want to take we can solve a lot of these
problems by moving all the fields that go optional together into a separate
struct:
We get even more type safety and clarity by making them separate types (and have ArmyWithDbProps wrap Army):
Or we could use Into if it's not appropriate for process_army_from_db to turn an ArmyWithDbProps into an Army:
Also this last example is using clone when if this is in-fact the direction you want to go we could be using pointers to avoid unnecessary clones. Let me know if this is the case and I can write a version with pointers and lifetimes.
I'm sure we've missed something here specific to your software (obviously the above links are all trivial examples), but I just wanted to help clarify my original point with some concrete code. If you can share some of your code we might be able to give you more specific advice.