Consistency
Consistency preserves invariants across records and systems.
What it is
Consistency preserves invariants across records and systems.
When to use it
Define the source of truth and what may lag.
Syntax
sum of debits = sum of credits per currency
transaction state matches recorded movementsExample
// Local invariant: debit + credit + record in one transaction.
// External settlement: durable pending/unknown state, stable reference,
// retry-safe processing, and reconciliation.Common mistakes
A local database transaction cannot atomically commit with an unrelated external provider.