Stock Tracking Within a Location: Zone-Level Inventory
Within each location, AccuArk can track stock at a more granular level using storage zones. This two-tier model lets you know not just that you have 500 units at your warehouse, but exactly which shelf, bin, or area those units are in.
The Two-Tier Stock Model
AccuArk tracks stock at two levels simultaneously:
| Level | Table | What It Tracks |
|---|---|---|
| Location Level | inventory_stock_location | Total quantity of an item at a location, last cost, last transaction date |
| Zone Level | inventory_stock_zone | Quantity of an item at a specific zone within a location, reserved quantity, last transaction date |
These two levels are maintained independently. When stock is received, moved, or adjusted, both the location-level and zone-level records are updated within the same database transaction.
Zone Stock Table Structure
The inventory_stock_zone table stores:
| Field | Description |
|---|---|
| item_id | The inventory item |
| location_id | The location this zone belongs to |
| zone_id | The specific storage zone |
| quantity | The current stock quantity in this zone |
| qty_reserved | The quantity reserved (e.g., for pending orders) |
| latest_transaction | Timestamp of the last stock change in this zone |
The Available quantity is calculated as: Available = Quantity - QtyReserved
Each unique combination of item + location + zone creates one record. The zone stock uses an UPSERT pattern: if a record already exists for the item/location/zone combination, the quantity is incremented or decremented. If no record exists, one is created.
Viewing Zone Stock on the Item Form
The item form has a Zone Stock tab that shows the dgvZoneStock grid. This grid displays the zone-level breakdown for the selected item across all locations:
| Column | Description |
|---|---|
| Location | The location name |
| Zone | The storage zone name, sorted by zone depth and sort order |
| Quantity | The current stock in this zone |
| Reserved | The reserved quantity |
| Available | Quantity minus Reserved |
Only zones with non-zero quantity or non-zero reserved quantity are shown. This keeps the view clean by hiding zones where the item has never been stocked.
How Zone Stock Updates
Zone stock is updated through four main operations:
1. Purchase Order Receiving
When stock is received on a PO, the system determines the target zone using the AccuArk's routing system (see Article 71). The received quantity is added to both the location-level stock and the zone-level stock for the resolved zone. If the user manually overrides the zone via the zone picker on the PO form, the override zone is used instead.
2. Stock Moves
When transferring stock, the From Zone and To Zone are specified on the stock move form. The transfer subtracts from the source zone and adds to the destination zone, all within the same atomic transaction.
3. Stock Adjustments
Adjustments can target a specific zone using the zone picker on the adjustment form. The adjustment quantity (positive or negative, based on the reason direction) is applied to both the location and zone stock.
4. Cycle Counts
Cycle counts can optionally be scoped to a specific zone. When finalized, the system generates adjustment transactions for each variance, and those adjustments target the zone that was counted.
Zone Stock vs. Location Stock
An important detail: the location total and the sum of zone quantities are maintained as independent aggregates. They may not always match exactly in these scenarios:
- Stock exists outside zones — If stock was added to a location before storage zones were set up, or if a receiving operation did not assign a zone, the stock exists at the location level but not in any zone
- Legacy data — Stock from before zone tracking was enabled may have location quantities without corresponding zone records
The location-level quantity is always the authoritative total for that location. Zone-level data provides the breakdown of where within the location the stock is physically stored.
The UPSERT Pattern
Zone stock changes use an INSERT ... ON DUPLICATE KEY UPDATE pattern:
INSERT INTO inventory_stock_zone (item_id, location_id, zone_id, quantity, latest_transaction)
VALUES (@item_id, @location_id, @zone_id, @quantity, NOW())
ON DUPLICATE KEY UPDATE
quantity = quantity + VALUES(quantity),
latest_transaction = NOW()This means:
- If no record exists for this item/location/zone, a new one is created with the given quantity
- If a record already exists, the quantity is incremented (or decremented for negative values)
- The timestamp is always updated
This approach eliminates race conditions and avoids the need to check whether a record exists before updating.
Tips
- Set up zones before receiving stock — If you create zones after stock has already been received, existing stock will not have zone assignments. You would need to perform stock adjustments or moves to assign existing stock to zones.
- Use the Zone Stock tab for warehouse audits — The zone-level breakdown shows exactly where items are stored, which is invaluable during physical counts
- Zone stock supports fractional quantities — Just like location stock, zone quantities can be fractional (e.g., 2.50 liters)
- The Unassigned zone catches unrouted stock — If no routing rule matches and the location's OverflowToUnassigned setting is enabled, stock goes to the system-managed Unassigned zone. This ensures stock is never lost, even without explicit routing.
- Querying zone stock — You can view all items at a specific zone using the Zone Explorer, or view all zones for a specific item using the Zone Stock tab on the item form