Of course the first thing that came to mind on this is xtdb @xtdb_com bitemporal database, where built in soft-deletes are part of bitemporality (first class). It is mentioned exactly once in the HS comments so far.
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RT @refset
A discussion about 'soft deletion' is currently #1 on HN! On reflection, "making soft deletes a first-class concept" feels like a useful way to frame 'bitemporality' for the uninitiated 💡
I'm looking forward to…
https://twitter.com/refset/status/1549517100158537730
We do soft deletes in PostGres with auto-generated views that permanently encode "undeleted" vs the raw table. But article's point of referential integrity is a big one.