# Transaction Boundary

> A rule or precondition that a transaction covers exactly the writes of one unit of work inside one service.

Record: `architecture:transaction-boundary`
Kind: constraint
Layer: [Atomic Boundary](https://banes-lab.com/records/layer/atomic-boundary.md)
Severity: mandatory
Scope: unit of work, aggregate, service
Canonical: https://banes-lab.com/ontology#architecture-transaction-boundary

Listed in [Architecture principles](https://banes-lab.com/api/records/architecture.md), after [ACID](https://banes-lab.com/records/architecture/acid.md) and before [Unit of Work Pattern](https://banes-lab.com/records/architecture/unit-of-work-pattern.md).

## Repair

- Refactored by: Shrink Boundary, Add Saga
- Detected by: transaction scope leakage
- Violated by: spanning transactions across service boundaries
- Measured by: transaction size/duration
- Enforced by: transaction policy

## Requires

- [Consistency Rules](https://banes-lab.com/records/lexicon/consistency-rules.md)

## Reinforces

- [Atomicity](https://banes-lab.com/records/architecture/atomicity.md)
- [Unit of Work Pattern](https://banes-lab.com/records/architecture/unit-of-work-pattern.md)

## Enables

- [Safe State Mutation](https://banes-lab.com/records/lexicon/safe-state-mutation.md)

## Conflicts with

- [Hidden Distributed Transaction](https://banes-lab.com/records/lexicon/hidden-distributed-transaction.md)

## In tension with

- [Large Transaction Scope](https://banes-lab.com/records/lexicon/large-transaction-scope.md)

## Tensions

- [Transaction Boundary / Large Transaction Scope](https://banes-lab.com/records/tension/large-transaction-scope-transaction-boundary.md)

## Contracts

- [Transaction Boundary](https://banes-lab.com/records/algorithms/transaction-boundary.md)

## Severity

- [mandatory](https://banes-lab.com/records/vocabulary/severity-mandatory.md)

## Category

- [Transactions / State / Concurrency](https://banes-lab.com/records/architecture-category/transactions-state-concurrency.md)

## Linked from

- [Separate, trade, or mitigate](https://banes-lab.com/software-architecture/principles/separate-trade-or-mitigate.md)
- [The principle architecture](https://banes-lab.com/software-architecture/glossary/the-principle-architecture.md)
- [Architectural rules and principles](https://banes-lab.com/software-architecture/glossary/architectural-principles.md)
- [Transactions / State / Concurrency](https://banes-lab.com/ontology/principles/architecture-category-transactions-state-concurrency.md)
- [Transactions / State / Concurrency](https://banes-lab.com/ontology/lexicon/lexicon-category-transactions-state-concurrency.md)
- [Architecture](https://banes-lab.com/ontology/algorithms/algorithms-domain-architecture.md)
- [Severity levels](https://banes-lab.com/ontology/schema/the-vocabulary-severity.md)
- [The resolutions](https://banes-lab.com/ontology/schema/the-resolutions.md)