sql - Is an overuse of nullable columns in a database a "code smell"?

Question

I'm just stepping into a project and it has a fairly large database backend. I've started digging through this database and 95% of the fields are nullable.

Is this normal practice in the database world? I'm just a lowly programmer, not a DBA but I would think you would want to keep nullable fields to a minimum, only where they make sense.

Is it a "code smell" if most columns are nullable?

Answer 1

Default values are typically the exception and NULLs are the norm, in my experience.

True, nulls are annoying.

It's also extremely useful because null is the best indicator of "NO VALUE". A concrete default value is very misleading, and you can lose information or introduce confusion down the road.