Explains why a physical table carries one rule set in Data Controller
(MPE_TABLES and MPE_VALIDATIONS are both keyed on the physical libref.dataset),
then covers the two ways to get more than one:
- two librefs over the same data (recommended - configuration only, no hooks,
no copies, filtering and every other editor behaviour unchanged)
- an empty mirror plus PRE_EDIT_HOOK (show the live rows) and POST_EDIT_HOOK
(re-point the changeset at the real table with call symputx, not %let). The
target table must itself be registered in MPE_TABLES.
Screenshots are from the demo estate.
