import peewee

from .database import db


class User(peewee.Model):
    email = peewee.CharField(unique=True, index=True)
    hashed_password = peewee.CharField()
    is_active = peewee.BooleanField(default=True)

    class Meta:
        database = db


class Item(peewee.Model):
    title = peewee.CharField(index=True)
    description = peewee.CharField(index=True)
    owner = peewee.ForeignKeyField(User, backref="items")

from contextvars import ContextVar

import peewee

DATABASE_NAME = "test.db"
db_state_default = {"closed": None, "conn": None, "ctx": None, "transactions": None}
db_state = ContextVar("db_state", default=db_state_default.copy())


class PeeweeConnectionState(peewee._ConnectionState):
    def __init__(self, **kwargs):
        super().__setattr__("_state", db_state)
        super().__init__(**kwargs)

    def __setattr__(self, name, value):

from typing import Any, List, Union

import peewee
from pydantic import BaseModel
from pydantic.utils import GetterDict


class PeeweeGetterDict(GetterDict):
    def get(self, key: Any, default: Any = None):
        res = getattr(self._obj, key, default)
        if isinstance(res, peewee.ModelSelect):
            return list(res)
        return res


class ItemBase(BaseModel):
    title: str
    description: Union[str, None] = None

    <root-XML localName="PremiereData"/>
    <sub-class-of type="application/xml"/>
  </mime-type>

  <mime-type type="image/vnd.cns.inf2"/>

  <!-- credit: peeveen's tika-dgn-detector https://github.com/peeveen/tika-dgn-detector/ -->
  <mime-type type="image/vnd.dgn">
    <glob pattern="*.dgn" />
    <glob pattern="*.dgnlib" />
    <glob pattern="*.cel" />
  </mime-type>

它可能有一个像`"Arquilian"`(一种业务逻辑)。

当您尝试从您的宠物对象访问它时，ORM 将完成所有工作以从相应的表*所有者那里再获取信息。*

常见的 ORM 例如：Django-ORM（Django 框架的一部分）、SQLAlchemy ORM（SQLAlchemy 的一部分，独立于框架）和 Peewee（独立于框架）等。

在这里，我们将看到如何使用**SQLAlchemy ORM**。

以类似的方式，您也可以使用任何其他 ORM。

/// tip

在文档中也有一篇使用 Peewee 的等效的文章。

///

## 文件结构

对于这些示例，假设您有一个名为的目录`my_super_project`，其中包含一个名为的子目录`sql_app`，其结构如下：

```
.
└── sql_app
    ├── __init__.py

* Fix Peewee `contextvars` handling in docs: [SQL (Relational) Databases with Peewee](https://fastapi.tiangolo.com/advanced/sql-databases-peewee/). PR [#879](https://github.com/tiangolo/fastapi/pull/879).

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