-- =============================================================================
-- MIGRATION: Persist the applied discount code(s) on the checkout session so
-- completeSession can increment DiscountCode.usedCount for exactly what was
-- actually charged (comma-joined when multiple stackable codes are applied).
-- Convention: Prisma maps createdAt→createdOn, updatedAt→updatedOn in DB
-- Run: idempotent — safe to re-execute
-- =============================================================================

BEGIN;

ALTER TABLE cart.checkout_sessions
  ADD COLUMN IF NOT EXISTS "discountCode" TEXT;

COMMIT;