This table summarizes which RLS policy expressions apply to each
command type, and whether they apply to the old or new tuples (or
both), which saves reading through a lot of text.

Rod Taylor, hacked on by me. Reviewed by Fabien Coelho.

Discussion: https://postgr.es/m/CAHz80e4HxJShm6m9ZWFrHW=pgd2KP=RZmfFnEccujtPMiAOW5Q@mail.gmail.com