# Database Transactions

> Define transaction boundaries, locking, and consistency guarantees for multi-step writes. Use when designing atomic operations, retries, idempotency, or concurrent write behavior.

- Skill: `hoangnguyen0403/database-transactions` (Agent Skill, multi-file: 3 files)
- Install (CLI): `npx skillmds@latest add hoangnguyen0403/database-transactions`
- Raw SKILL.md: https://api.skillmd.com/api/skills/hoangnguyen0403/database-transactions/raw
- Safety review: pending (external: skill-scanner PASS, skillspector PASS)
- Works with: Claude Code, Claude.ai, OpenAI Codex
- Category: Coding & Dev Tools
- Author: HoangNguyen0403 (https://skillmd.com/u/hoangnguyen0403)
- Updated: 2026-09-09
- Page: https://skillmd.com/skills/hoangnguyen0403/database-transactions

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# 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.

## Anti-Patterns

- **No giant transaction scripts**: long units increase contention and failure blast radius.
- **No retry without idempotency**: duplicate writes become correctness bugs.
- **No mixed atomicity story**: define what is immediate vs eventual.

## References

- [Framework Map](../references/framework-map.md)
- [Isolation Levels](references/isolation-levels.md)