[B]What changes need to be made to the above database definition in order to solve al

Building on the thread: preserve a stable row identity for order lines, stop changing the original ordered quantity, and record shipments separately. That directly solves the datagrid re-ordering, enables partial deliveries, and lets orders remain editable until a picklist is printed. (A note about @Comatose: subtracting shipped qty from the ordered amount is fragile — keep the original ordered quantity immutable and record shipments instead.)

Schema changes (key fields)

• Give each order-line a surrogate primary key (e.g. OrderLineID AUTONUMBER) and a LinePosition integer used for display/order. Bind the grid ordered by LinePosition so insertion or key changes do not reorder rows.
• Keep QtyOrdered (original), add QtyAllocated (reserved), and track shipments via QtyShipped derived from shipment records (or omit and compute sum of shipment lines).
• Add PicklistPrinted (boolean) and PicklistPrintedDate to the Order header to control edit-locking.
• Add new tables: Shipment and ShipmentLine to record each physical dispatch; optionally Allocation or InventoryTransaction to manage reservations and stock movements.

Example table queries and small DDL

SELECT * FROM OrderLine WHERE OrderNo=123 ORDER BY LinePosition;

Simple Access-style DDL sketches:

CREATE TABLE OrderLine (OrderLineID AUTOINCREMENT PRIMARY KEY, OrderNo LONG, LinePosition INTEGER, StockNo LONG, QtyOrdered LONG, QtyAllocated LONG DEFAULT 0);
CREATE TABLE Shipment (ShipmentID AUTOINCREMENT PRIMARY KEY, OrderNo LONG, ShipmentDate DATETIME);
CREATE TABLE ShipmentLine (ShipmentLineID AUTOINCREMENT PRIMARY KEY, ShipmentID LONG, OrderLineID LONG, QtyShipped LONG);

Process/workflow notes

• Allocation: when stock arrives, allocate to open order-lines (FIFO by OrderDate/LinePosition) and update QtyAllocated or create Allocation rows.
• Picklist: create a Picklist record (or set PicklistPrinted=true) and freeze edits at that point; generate Shipment/ShipmentLine entries when items are dispatched. Use application/form logic to prevent edits after PicklistPrinted.
• Reordering in the grid: on insert assign LinePosition = MAX(LinePosition)+1; to move lines swap LinePosition values rather than renumbering everything.

Implementation cautions

• Do not mutate the original QtyOrdered value as suggested by @Comatose; auditing and traceability require preserving original orders. Use separate shipment/allocation records for stock movements. In Access, enforce referential integrity, index OrderNo, LinePosition, and use form-level checks (BeforeUpdate) to block edits after picklist printing.