Kandiantong: A move from an old mall can bring only active members
Start with the conclusion: dual running is for orders already in transit, not for acquiring customers through two entrances at the same time. New customers enter only the new system.
What moves
Export fields from the old product change with the version. When a project starts, use the actual export file and the payment provider's statement. This article gives the acceptance criteria.
The old system handles orders that were already paid before the switch. The new system receives new orders after the switch. Member balance can be spent on only one side, so the same money is not spent twice. Ads, menus, and group announcements change to the new entrance on the same day.
What does not move
Do not issue coupons from both systems at once, do not let both systems change the same warehouse stock, and do not let distributors choose which side an order is opened on. During the move, only this class of data is carried. The difference is that only one entrance takes new orders. Overwriting the whole database would also bring in logs, test orders, and balances that cannot be explained.
Mapping checks and the switch
After the switch, the order button on the old system is unavailable. Inventory for orders in the new system is written back to the single inventory source. The balance ledger does not change. Keep the parallel period short, reconcile once a day, and close the old entrance only after three days in a row with no difference.
The import script must be safe to run again without creating duplicate data. Failed rows stay in the failure table. They must not enter a default grade or a default warehouse. Business and finance look at the totals together. If they do not match, stop at the rehearsal and do not change the mini-program entrance. Whether a payment succeeded follows the payment provider's statement, not a paid status in the old back office.