file = UploadFile(filename="file", file=stream, size=4)
    assert await file.read() == b"data"
    assert file.size == 4
    await file.write(b" and more data!")
    assert await file.read() == b""
    assert file.size == 19
    await file.seek(0)
    assert await file.read() == b"data and more data!"

=== "Python 3.10+"

    ```Python hl_lines="19-22  26-27"
    {!> ../../../docs_src/security/tutorial002_an_py310.py!}
    ```

=== "Python 3.9+"

    ```Python hl_lines="19-22  26-27"
    {!> ../../../docs_src/security/tutorial002_an_py39.py!}
    ```

=== "Python 3.8+"

    ```Python hl_lines="20-23  27-28"

    ```

=== "Python 3.8+"

    ```Python hl_lines="19-21"
    {!> ../../../docs_src/body_multiple_params/tutorial001_an.py!}
    ```

=== "Python 3.10+ non-Annotated"

    !!! tip "Заметка"
        Рекомендуется использовать `Annotated` версию, если это возможно.

    ```Python hl_lines="17-19"
    {!> ../../../docs_src/body_multiple_params/tutorial001_py310.py!}
    ```

现在，您可以使用这个类来声明你的依赖项了。

=== "Python 3.10+"

    ```Python hl_lines="17"
    {!> ../../../docs_src/dependencies/tutorial002_py310.py!}
    ```

=== "Python 3.6+"

    ```Python hl_lines="19"
    {!> ../../../docs_src/dependencies/tutorial002.py!}
    ```

**FastAPI** 调用 `CommonQueryParams` 类。这将创建该类的一个 "实例"，该实例将作为参数 `commons` 被传递给你的函数。

## 类型注解 vs `Depends`

注意，我们在上面的代码中编写了两次`CommonQueryParams`：

# A Pydantic model
class User(BaseModel):
    id: int
    name: str
    joined: date
```

これは以下のように用いられます:

```Python
my_user: User = User(id=3, name="John Doe", joined="2018-07-19")

second_user_data = {
    "id": 4,
    "name": "Mary",
    "joined": "2018-11-30",
}

my_second_user: User = User(**second_user_data)
```

!!! info "情報"
    `**second_user_data` は以下を意味します：

    而 Pydantic 也使用“模型”这个术语 来指代不同的东西，即数据验证、转换以及文档类和实例。

从`database`（来自上面的`database.py`文件）导入`Base`。

创建从它继承的类。

这些类就是 SQLAlchemy 模型。

```Python hl_lines="4  7-8  18-19"
{!../../../docs_src/sql_databases/sql_app/models.py!}
```

这个`__tablename__`属性是用来告诉 SQLAlchemy 要在数据库中为每个模型使用的数据库表的名称。

### 创建模型属性/列

现在创建所有模型（类）属性。

这些属性中的每一个都代表其相应数据库表中的一列。

*  `limit` 🔢 🔢 👈 `int`, ⏮️ 🔢 `100`.

👯‍♂️ 💼 💽 🔜 🗜, ✔, 📄 🔛 🗄 🔗, ♒️.

## ⚙️ ⚫️

🔜 👆 💪 📣 👆 🔗 ⚙️ 👉 🎓.

=== "🐍 3️⃣.6️⃣ & 🔛"

    ```Python hl_lines="19"
    {!> ../../../docs_src/dependencies/tutorial002.py!}
    ```

=== "🐍 3️⃣.1️⃣0️⃣ & 🔛"

    ```Python hl_lines="17"
    {!> ../../../docs_src/dependencies/tutorial002_py310.py!}
    ```

{!../../../docs_src/extra_data_types/tutorial001.py!}
```

Note que os parâmetros dentro da função tem seu tipo de dados natural, e você pode, por exemplo, realizar manipulações normais de data, como:

```Python hl_lines="18-19"
{!../../../docs_src/extra_data_types/tutorial001.py!}

    ```

Обратите внимание, что параметры внутри функции имеют свой естественный тип данных, и вы, например, можете выполнять обычные манипуляции с датами, такие как:

=== "Python 3.8 и выше"

    ```Python hl_lines="18-19"
    {!> ../../../docs_src/extra_data_types/tutorial001.py!}
    ```

=== "Python 3.10 и выше"

    ```Python hl_lines="17-18"
    {!> ../../../docs_src/extra_data_types/tutorial001_py310.py!}

E você também pode declarar parâmetros de corpo como opcionais, definindo o valor padrão com `None`:

=== "Python 3.10+"

    ```Python hl_lines="17-19"
    {!> ../../../docs_src/body_multiple_params/tutorial001_py310.py!}
    ```

=== "Python 3.8+"

    ```Python hl_lines="19-21"
    {!> ../../../docs_src/body_multiple_params/tutorial001.py!}
    ```

!!! note "Nota"