Comment by codingdave
2 days ago
How would the database know whether the other app layers depend on that value or not? You could absolutely have an app that does not require data in a specific field to function, yet all records happen to have data. This is actually fairly common in single-tenant apps, where some tenants populate a field and others do not. You need to look at how the data is used across the entire stack to know whether or not it should be nullable, not whatever the current data happens to be.
The script example in TFA is just a starting point. I believe you would still manually go through all the columns it finds and decide which ones are actually supposed to be nullable and which ones don't need to be. As the article said, nullable fields that don't contain null could be a sign of incomplete migrations and such.
It doesn't. That's why it's the responsibility of the application layer to correctly implement the data model of the database and not the other way around