text: ALTER TABLE "event"
      ALTER COLUMN "identity_id" SET DEFAULT
          coalesce(
              current_setting('tenant.identity_id', true)::uuid,
              '00000000-0000-0000-0000-000000000000'
          ),
  
      ALTER COLUMN "transaction_id" SET DEFAULT
          coalesce(
              nullif(current_setting('system.transaction_id', true), '')::uuid,
              set_config('system.transaction_id', uuid_generate_v4()::text, true)::uuid
          );
  