We've seen a few cascading errors (e.g. comment.activityId would be non
nullable but cascade behavior is set to "set null"). I think it's safer
if we have to explicitly chose the deletion behavior it every time.
Especially since Postgres default to "No action" while we defaulted to
"Set Null", which is confusing.
In the future we will most likely introduce a second param
`onSoftDelete` in the decorator
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