If you have an old FastAPI app with Pydantic v1, here I'll show you how to migrate it to Pydantic v2, and the **features in FastAPI 0.119.0** to help you with a gradual migration.

## Official Guide { #official-guide }

Pydantic has an official [Migration Guide](https://docs.pydantic.dev/latest/migration/) from v1 to v2.

It also includes what has changed, how validations are now more correct and strict, possible caveats, etc.

⚠️ Do not install this package. ⚠️

This package, `fastapi-slim`, does nothing other than depend on `fastapi`.

All the functionality has been integrated into `fastapi`.

The only reason this package exists is as a migration path for old projects that used to depend on `fastapi-slim`, so that they can get the latest version of `fastapi`.

You **should not** install this package.

Install instead:

```bash
pip install fastapi
```

* Existing usages of Java serialization should be migrated to use it.
* It is ok for Serializer to be used as a replacement for Java serialization as a migration step.

### Negative Consequences

* **Historical inconsistencies**: Existing code may contain British English spellings that cannot be changed due to backward compatibility

### Migration and Enforcement

* **New code**: All new contributions must use American English

## Migration from another search provider

Please see [MIGRATION.md](MIGRATION.md).

## Data Store

Currently, Fess supports crawling the following [storage locations and APIs](https://fess.codelibs.org/15.5/admin/dataconfig-guide.html):

Pydantic v1을 사용하는 오래된 FastAPI 앱이 있다면, 여기서는 이를 Pydantic v2로 마이그레이션하는 방법과 점진적 마이그레이션을 돕는 **FastAPI 0.119.0의 기능**을 소개하겠습니다.

## 공식 가이드 { #official-guide }

Pydantic에는 v1에서 v2로의 공식 [마이그레이션 가이드](https://docs.pydantic.dev/latest/migration/)가 있습니다.

여기에는 무엇이 바뀌었는지, 검증이 이제 어떻게 더 정확하고 엄격해졌는지, 가능한 주의사항 등도 포함되어 있습니다.

변경된 내용을 더 잘 이해하기 위해 읽어보면 좋습니다.

## 테스트 { #tests }

앱에 대한 [테스트](../tutorial/testing.md)가 있는지 확인하고, 지속적 통합(CI)에서 테스트를 실행하세요.

///

如果你的舊 FastAPI 應用仍使用 Pydantic v1，這裡會示範如何遷移到 Pydantic v2，並介紹 **FastAPI 0.119.0** 中可協助你逐步遷移的功能。

## 官方指南 { #official-guide }

Pydantic 提供從 v1 遷移到 v2 的官方[遷移指南](https://docs.pydantic.dev/latest/migration/)。

其中包含變更內容、驗證如何更正確且更嚴格、可能的注意事項等。

你可以先閱讀以更好理解具體變更。

## 測試 { #tests }

確保你的應用有[測試](../tutorial/testing.md)，並在 CI（持續整合）上執行。

如此一來，你可以升級後確認一切仍如預期運作。

## `bump-pydantic` { #bump-pydantic }

Here we create the tables on an application startup event.

For production you would probably use a migration script that runs before you start your app. 🤓

/// tip

SQLModel will have migration utilities wrapping Alembic, but for now, you can use [Alembic](https://alembic.sqlalchemy.org/en/latest/) directly.

///

### Create a Hero { #create-a-hero }

///

如果你的旧 FastAPI 应用在用 Pydantic v1，这里将向你展示如何迁移到 Pydantic v2，以及 FastAPI 0.119.0 中可帮助你渐进式迁移的功能。

## 官方指南 { #official-guide }

Pydantic 有一份从 v1 迁移到 v2 的官方[迁移指南](https://docs.pydantic.dev/latest/migration/)。

其中包含变更内容、校验如何更准确更严格、可能的注意事项等。

你可以阅读以更好地了解变更。

## 测试 { #tests }

请确保你的应用有[测试](../tutorial/testing.md)，并在持续集成（CI）中运行它们。

这样你就可以升级并确保一切仍按预期工作。

## `bump-pydantic` { #bump-pydantic }

    "docs_src/dependencies/tutorial013_an_py310.py",  # temporary code example?
    "docs_src/dependencies/tutorial014_an_py310.py",  # temporary code example?
    # Pydantic v1 migration, no longer tested
    "docs_src/pydantic_v1_in_v2/tutorial001_an_py310.py",
    "docs_src/pydantic_v1_in_v2/tutorial002_an_py310.py",
    "docs_src/pydantic_v1_in_v2/tutorial003_an_py310.py",