# 使用数据类

FastAPI 基于 **Pydantic** 构建，前文已经介绍过如何使用 Pydantic 模型声明请求与响应。

但 FastAPI 还可以使用数据类（<a href="https://docs.python.org/3/library/dataclasses.html" class="external-link" target="_blank">`dataclasses`</a>）：

{* ../../docs_src/dataclasses_/tutorial001.py hl[1,7:12,19:20] *}

这还是借助于 **Pydantic** 及其<a href="https://pydantic-docs.helpmanual.io/usage/dataclasses/#use-of-stdlib-dataclasses-with-basemodel" class="external-link" target="_blank">内置的 `dataclasses`</a>。

   * are responsible for taking the mutex themselves:
   * https://docs.oracle.com/en/java/javase/22/docs/api/java.base/java/util/Collections.html#synchronizedCollection(java.util.Collection)
   *
   * Similarly, we avoid having those methods *implemented* in terms of *other* TestSet methods
   * that will perform holdsLock assertions:
   *

package s3select

import "strings"

// SelectError - represents s3 select error specified in
// https://docs.aws.amazon.com/AmazonS3/latest/API/RESTObjectSELECTContent.html#RESTObjectSELECTContent-responses-special-errors.
type SelectError interface {
	Cause() error
	ErrorCode() string
	ErrorMessage() string
	HTTPStatusCode() int
	Error() string
}

type s3Error struct {

lass/ ## runtimeClassName: "" ## Set default rootUser, rootPassword ## AccessKey and secretKey is generated when not set ## Distributed MinIO ref: https://min.io/docs/minio/linux/operations/install-deploy-manage/deploy-minio-multi-node-multi-drive.html ## rootUser: "" rootPassword: "" ## Use existing Secret that store following variables: ## ## | Chart var | .data.<key> in Secret | ## |:-------- ## | rootUser | rootUser | ## | rootPassword | rootPassword | ## ## All mentioned variables will be ignored...

lass/ ## runtimeClassName: "" ## Set default rootUser, rootPassword ## AccessKey and secretKey is generated when not set ## Distributed MinIO ref: https://min.io/docs/minio/linux/operations/install-deploy-manage/deploy-minio-multi-node-multi-drive.html ## rootUser: "" rootPassword: "" ## Use existing Secret that store following variables: ## ## | Chart var | .data.<key> in Secret | ## |:-------- ## | rootUser | rootUser | ## | rootPassword | rootPassword | ## ## All mentioned variables will be ignored...

lass/ ## runtimeClassName: "" ## Set default rootUser, rootPassword ## AccessKey and secretKey is generated when not set ## Distributed MinIO ref: https://min.io/docs/minio/linux/operations/install-deploy-manage/deploy-minio-multi-node-multi-drive.html ## rootUser: "" rootPassword: "" ## Use existing Secret that store following variables: ## ## | Chart var | .data.<key> in Secret | ## |:-------- ## | rootUser | rootUser | ## | rootPassword | rootPassword | ## ## All mentioned variables will be ignored...

lass/ ## runtimeClassName: "" ## Set default rootUser, rootPassword ## AccessKey and secretKey is generated when not set ## Distributed MinIO ref: https://min.io/docs/minio/linux/operations/install-deploy-manage/deploy-minio-multi-node-multi-drive.html ## rootUser: "" rootPassword: "" ## Use existing Secret that store following variables: ## ## | Chart var | .data.<key> in Secret | ## |:-------- ## | rootUser | rootUser | ## | rootPassword | rootPassword | ## ## All mentioned variables will be ignored...

lass/ ## runtimeClassName: "" ## Set default rootUser, rootPassword ## AccessKey and secretKey is generated when not set ## Distributed MinIO ref: https://min.io/docs/minio/linux/operations/install-deploy-manage/deploy-minio-multi-node-multi-drive.html ## rootUser: "" rootPassword: "" ## Use existing Secret that store following variables: ## ## | Chart var | .data.<key> in Secret | ## |:-------- ## | rootUser | rootUser | ## | rootPassword | rootPassword | ## ## All mentioned variables will be ignored...

lass/ ## runtimeClassName: "" ## Set default rootUser, rootPassword ## AccessKey and secretKey is generated when not set ## Distributed MinIO ref: https://min.io/docs/minio/linux/operations/install-deploy-manage/deploy-minio-multi-node-multi-drive.html ## rootUser: "" rootPassword: "" ## Use existing Secret that store following variables: ## ## | Chart var | .data.<key> in Secret | ## |:-------- ## | rootUser | rootUser | ## | rootPassword | rootPassword | ## ## All mentioned variables will be ignored...

使用上面的任何方法，它在 `/docs` 中看起来都是这样的:

<img src="/img/tutorial/body-fields/image01.png">

## 技术细节

关于 `example` 和 `examples`...

JSON Schema在最新的一个版本中定义了一个字段 <a href="https://json-schema.org/draft/2019-09/json-schema-validation.html#rfc.section.9.5" class="external-link" target="_blank">`examples`</a> ，但是 OpenAPI 基于之前的一个旧版JSON Schema，并没有 `examples`.