[pdpi]

Frankly, the idea that there must be sensible default worries me.

Take a database of people. There is literally no sensible default for name, age, gender, height, weight, social security...

If you’re amazon, your products have no sensible default for manufacturer, shipping weight/size, delivery address...

In fact, for just about any real-world data, there simply is no sensible default for anything at all. Most “sensible” defaults will eventually bite you in the arse. The only sane way to keep nulls from your DB is to refuse inserting incomplete data in the first place, and propagate the error to the user. Heavens save your team if you’re dealing with batch data and insist on not allowing nulls in the DB, though.

You can sweep this mess under a rug and pretend you have no nulls by turning things into relations that are allowed to be empty — “there are no delivery_address rows for this user” — but that’s a null in sheep’s clothing. Either your application knows how to deal with the query coming up empty, or it doesn’t.