Odoo Stock Tracking: Identity and Quantity Management¶

Purpose: Explain Odoo's stock tracking architecture, the relationship between events and state, and how identity assignment prevents double counting.

Audience: System architects, migration teams, operations personnel implementing serial number tracking.

1. Stock as Event-Driven State¶

Stock is not a table or a number. Stock is a system with two complementary parts:

Events – what happened → stock.move.line
State – what is true now → stock.quant
Moves are history (ledger)
Quants are current balance (snapshot)
State is always derived from events

This separation is foundational to understanding tracking behavior.

2. Three Tracking Modes = Three Identity Regimes¶

Every product has exactly one tracking mode:

A. No Tracking¶

Only quantity matters
Units are anonymous
System only enforces total quantity

Quant: product A, lot_id = NULL, qty = N

This represents bulk inventory management without individual unit identity.

B. Lot (Batch) Tracking¶

Group identity, not unit identity
Units are fungible within the same lot
Quantity can be split or merged
History matters, unit uniqueness does not

Quant: product A, lot_id = LOT-X, qty = N

A lot is not a collection of serials. It is a label shared by many anonymous units.

C. Serial Tracking¶

Unit identity
One serial = one physical unit
Quantity is always 1
No fungibility, no merging, no downgrade

Quant: product A, lot_id = SERIAL-123, qty = 1

A serial is a lot with quantity = 1.

3. Tracking Mode as Capability¶

Tracking mode is a capability, not an action.

tracking = serial means:

“This product may have identity, and identity will be enforced when required.”

It does not mean:

every unit already has a serial
identity exists automatically

Identity only exists once a serial number is actually assigned.

4. Serialization Is a One-Way Boundary¶

You can think in terms of two domains:

Non-identity domain¶

No serials
Only quantities
Governed by total balance

Identity domain¶

Serial numbers exist
Quantity fixed at 1 per serial
Governed by exclusivity

Crossing the boundary happens at a stock move.

When serials are assigned:

Anonymous quantity decreases
Serialized units appear
Total quantity is conserved

There is no double counting, because:

identity creation always consumes quantity.

Once serialized:

A unit can never go back
No merging
No downgrade to lot or non-tracking

5. Why Cutover from Non-Tracking Is Safe¶

Even if a product was historically non-tracked:

You can switch tracking = serial
Existing stock remains anonymous
Nothing breaks

Those units simply:

are not yet identity-bearing
are not eligible for asset-level services

When you later:

receive
internally transfer
adjust inventory
deliver

…and serials are required:

➡️ serials are injected at that moment

Balance holds:

Before: qty = 100
After:  qty = 70 (anonymous) + 30 serials

No overlap. No duplication.

6. Why Location and “Receiving” Moves Matter¶

Serials can be assigned at:

manufacturing completion
incoming receipt
internal transfer
delivery

These are transaction boundaries where Odoo allows:

quantity to move
identity to be injected

This flexibility supports:

Migration scenarios (anonymous → serialized)
Field stock management
Late labeling workflows

7. Lot Tracking Is Intentionally “Weak”¶

Lot tracking allows:

fungibility within a batch
traceability between batches
history without unit determinism

So yes:

physical units inside the same lot can be swapped
state may end up identical after moves
but history still records what happened

This is acceptable only if unit-level enforcement is not required.

If unit-level integrity matters → use serial tracking.

8. Serial Numbers Are Logically Immutable (Critical Rule)¶

Technically:

Odoo lets you edit serial names

Practically:

You must treat serials as immutable asset identity

Changing serials breaks:

traceability
audit
contracts
services
IoT linkage

Operational requirement: Serial edit rights must be restricted. Treat serials as write-once identifiers.

9. Why There Is No Double Counting (Final Aha)¶

Because:

Anonymous quantity and serialized units live in disjoint stock domains
A unit cannot exist in both at once
Crossing domains always conserves quantity

Non-tracking and serial tracking do not compete — they coexist safely.

10. Summary¶

Odoo stock is managed as events and derived state. Products may be non-tracked, lot-tracked, or serial-tracked. Tracking mode enables identity but does not create it. Identity is injected only at stock move boundaries, consuming anonymous quantity and preserving balance. Non-tracked stock has no notion of uniqueness, lot tracking provides batch-level identity with fungibility, and serial tracking provides immutable unit-level identity. Once serialized, a unit never returns to anonymity, and double counting is structurally impossible.