Database Transactions

Priority: P0 (CRITICAL)

One business action should have one clear consistency strategy.

Rules

• Define the unit of work before choosing transaction scope.
• Keep transaction bodies short and purposeful.
• Record isolation, lock, retry, and idempotency expectations for contested writes.
• Split eventually consistent workflows from truly atomic ones.

Verify

• Transaction boundary matches one business action.
• Isolation or locking tradeoff is explicit.
• Retry and idempotency behavior is defined for duplicate or concurrent requests.
• External side effects are not hidden inside a DB transaction without compensation.