[pornel]

Nah.

Everyone here seems to be super diligent about FKs. I wonder if that's a sampling bias.

I've worked on a few projects where they were considered an unnecessary hassle, especially when the RDMS had some performance or functionality limitations when using them. Also "on delete cascade" seems scary. Plenty of systems even just set deleted=true instead of actually deleting (at least before GDPR).

Not every CRUD app treats data integrity as a holy grail. A social network for hamsters can lose a comment, no big deal. Some applications threat databases as a bag of key-value pairs, and the inconvenience of migrations ends up with a JSON in an "everything_else" column. Move fast and break relational integrity.