Maintain stock balances through movement and allocation ledgers

Context

Concurrent promises and physical movements need balances backed by retained facts.

Decision

Maintain stock balances through movement and allocation triggers and derive available stock in the database.

Alternatives Considered

Permit direct service balance writes alongside ledger entries. Independent balance writes can diverge from the ledgers that explain them.

Derive all availability from ledgers on each read. Claims need current constrained balances while their transaction runs.

Consequences

Opening imports and corrections use ledger movements. Reconciliation can rederive balances without silently assigning replacements.