The best advice I can give is that you can think of your app and its data store as either:

#1 code is of prime importance, data store is simply a "bucket" for its data

#2 data is of prime importance, code is simply the means to read/write/display it

In my personal experience, #2 is a way better way to work. Apps can come and go, but data can last a long time, and the better your database is modelled the better the outcomes you'll have long term.

Corollary - I have seen some abject disasters where #1 has been adopted. Not necessarily just because of #1 alone but it's certainly been a major factor.

> In my personal experience, #2 is a way better way to work. Apps can come and go, but data can last a long time

Exactly. Data is far more valuable than code. We still work with data from literally centuries ago. Most programs written even 10 years ago are probably no longer in use. I would be surprised if the oldest code still doing something useful was more than 20 or so years old.

> I would be surprised if the oldest code still doing something useful was more than 20 or so years old.

...you can't be serious? Every other company that has been writing code for 20+ years probably has code that is 20+ years old. Just look at banks.

It's an incorrect impression, obviously.

For >20 year old code, Calc.exe is just one example off the top of my head - https://github.com/Microsoft/calculator

The majority of the products I've personally worked on over my 15 year career in software development are still doing useful things and contain code written more than 20 years ago.