Comment by perrygeo

The whole model of RDBMS is based on mutable tuples; soft deletes don't make much sense as an intrinsic part of that model. If you want soft deletes, you create an application layer or use a different data model.

Most of the time if you want "soft deletes", you really want an immutable log so that you time travel to any point in the history. XTDB and Datomic are worth looking at if you want to solve the problem at the data model level.