The inventory ledger

The inventory ledger is the audit trail. Stock movements, planning projections, disposition moves, and cost-only changes are appended as events; projected balance tables make those events fast to read.

append-onlyidempotent writesfilterable

What one event holds

Field group	Holds
Where	Organization, location, item, and optional lot.
What changed	Event type, positive quantity, unit cost, extended cost, and disposition fields.
Why	Reference type/id, parent event, event subtype, adjustment reason, and notes metadata.
Who and when	Actor, occurred timestamp, and idempotency key.

Stock event quantities are positive; the event type determines whether the movement increases or decreases stock. Cost-only events use quantity 0. Demand and expected-supply events have no lot or cost.

How to read the ledger

1. Filter to the surface you care about. The app supports filters for event type, movement class, item, document type/id, actor, occurrence date, lot, and text.
2. Read the source/cause. Purchase receipts, sales consumption, manufacturing events, stocktakes, transfers, and adjustments link back to the source where the code can resolve one.
3. Compare before and after. On-hand event rows show signed movement and on-hand before/after when the ledger can calculate it.
4. Use cost fields for valuation history. Stock events carry unit and extended cost. Revaluation events show cost-only changes.

Projections built from it

Projection	Grain	Holds
inventory_lot_balances	item x location x lot x disposition	Quantity, unit cost, received date, origin event, active flag.
inventory_item_balances	item x location	On hand, demand, expected, available to promise, last verified date.
inventory_expected_summary	item x location x reference	Remaining expected supply by source document.
inventory_demands_summary	item x location x reference	Remaining demand by source document.

Use the ledger when balances look surprising

The balance is the answer; the ledger explains how the app got there. Start from the item, lot, or source document, then narrow by event type and date.