What Is an Inventory Ledger? Append-Only Stock Truth Explained

An inventory ledger is the append-only, signed record of every stock movement for a part, and the sum of its entries is the only authoritative on-hand figure. A positive quantity is a receipt into stock, a negative quantity is an issue out of it, and nothing is ever edited or deleted. When a movement is wrong, you correct it with an opposite reversal entry, not by erasing the original. That single design choice is what lets an inventory ledger stay trustworthy through years of reschedules, corrections, and audits.

This entry defines the concept and shows how it behaves inside EDGEBIC by User Solutions. For the broader index of planning terms, see the manufacturing glossary, and for a closely related figure, see projected available balance.

How it works

Think of an inventory ledger the way you think of a bank statement. One line reads "July 4, Salary In, +3,000, Balance 5,200." The next reads "July 5, Rent Out, -1,800, Balance 3,400." You never scribble over an old line to fix a mistake. You add a correcting line. The running balance after each entry is carried forward, and the sum of every line is your true balance.

An inventory ledger works identically. Each entry carries a signed quantity, a transaction type (receipt, issue, adjustment, opening balance, or a reversal of one of those), an effective date for planning, a unit cost captured at post time, and the running balance after that movement. Entries also carry provenance: which manufacturing order, schedule row, or material step drove the movement, and what the demand source was.

Two movement directions matter most. A receipt (positive) posts when a build-to-stock order completes and puts finished goods on the shelf, marked with the comment "Build to Inventory." An issue (negative) posts when a demand is satisfied from existing stock rather than by building, marked "Schedule Transaction." Both directions flow through one transactional path that reads the current sum, appends the entry, recomputes the cached on-hand, and only then broadcasts the change to the rest of the application.

The append-only rule is not a preference; it is the guarantee. Because no row is ever mutated, the sum is reproducible, the past is immutable, and any figure that trusts on-hand can trust it completely.

A concrete example

A shop starts with zero Widget A on hand. A make-to-stock order for 200 units completes, and the ledger gets its first entry:

A customer order for 80 units arrives. Because 200 are already on the shelf, the scheduling engine satisfies it from stock rather than building. At the persist step it posts an issue:

On-hand is now 120, and it is 120 because 200 minus 80 equals 120, a fact you can verify by reading two rows. If that customer order is later cancelled, the ledger does not lose entry 2. It gains entry 3, a +80 reversal that restores the balance to 200 and marks the original as reversed. Both the issue and its reversal survive, so the record shows exactly what was committed and exactly when it was undone.

How EDGEBIC uses it

In EDGEBIC, the inventory ledger is the single source of truth for stock, and every other inventory figure derives from it. The Transaction History view for a part displays the ledger directly, and the balance it shows is the same sum the scheduling engine nets against when it decides whether to build or consume from stock. Manual corrections go through the Adjustments screen, which appends a signed adjustment rather than overwriting a number.

The ledger also underpins reschedule safety. Every time a job is rescheduled, EDGEBIC reverses the job's prior stock issue before posting a new one, so repeated rescheduling can never leave a phantom balance. When an order is deleted or reopened, all of its pegged entries are reversed, and the entries themselves survive with their order link cleared, preserving the audit trail even after the order row is gone. Anomaly checks watch for the two failure modes that matter: a cached on-hand that has drifted from the ledger sum, and a physical balance that has gone negative because more was issued than was ever received.

To see the receipt side of the ledger in a full walkthrough, read the EDGEBIC inventory ledger explained mechanism post, which traces a build-to-stock cycle end to end. To understand how those ledger balances project forward into a planning calendar, continue with projected available balance and consume-from-stock netting.