> Because NULL values are of unknown equality to one another, they do not violat...

layer8 on July 11, 2022 | parent | context | favorite | on: Postgres 15 improves UNIQUE and NULL

> Because NULL values are of unknown equality to one another, they do not violate UNIQUE constraints.

Well, arguably you don’t know whether they violate uniqueness, so inserting more than one shouldn’t have been allowed.