```

////

//// tab | 🐍 3️⃣.9️⃣ & 🔛

```Python hl_lines="14"
{!> ../../docs_src/body_nested_models/tutorial002_py39.py!}
```

////

//// tab | 🐍 3️⃣.1️⃣0️⃣ & 🔛

```Python hl_lines="12"
{!> ../../docs_src/body_nested_models/tutorial002_py310.py!}
```

////

## ⚒ 🆎

✋️ ⤴️ 👥 💭 🔃 ⚫️, & 🤔 👈 🔖 🚫🔜 🚫 🔁, 👫 🔜 🎲 😍 🎻.

## Parâmetros opcionais

Da mesma forma, você pode declarar parâmetros de consulta opcionais, definindo o valor padrão para `None`:

//// tab | Python 3.10+

```Python hl_lines="7"
{!> ../../docs_src/query_params/tutorial002_py310.py!}
```

////

//// tab | Python 3.8+

```Python hl_lines="9"
{!> ../../docs_src/query_params/tutorial002.py!}
```

////

Аналогично, вы можете объявлять необязательные query-параметры, установив их значение по умолчанию, равное `None`:

//// tab | Python 3.10+

```Python hl_lines="7"
{!> ../../docs_src/query_params/tutorial002_py310.py!}
```

////

//// tab | Python 3.8+

```Python hl_lines="9"
{!> ../../docs_src/query_params/tutorial002.py!}
```

////

在 `Field`, `Path`, `Query`, `Body` 和其他你之后将会看到的工厂函数，你可以为JSON 模式声明额外信息，你也可以通过给工厂函数传递其他的任意参数来给JSON 模式声明额外信息，比如增加 `example`:

//// tab | Python 3.10+

```Python hl_lines="2  8-11"
{!> ../../docs_src/schema_extra_example/tutorial002_py310.py!}
```

////

//// tab | Python 3.8+

```Python hl_lines="4  10-13"
{!> ../../docs_src/schema_extra_example/tutorial002.py!}
```

////

/// warning

    "tax": 3.2
}
```

But you can also declare multiple body parameters, e.g. `item` and `user`:

//// tab | Python 3.10+

```Python hl_lines="20"
{!> ../../docs_src/body_multiple_params/tutorial002_py310.py!}
```

////

//// tab | Python 3.8+

```Python hl_lines="22"
{!> ../../docs_src/body_multiple_params/tutorial002.py!}
```

////

    "tax": 3.2
}
```

Aber Sie können auch mehrere Body-Parameter deklarieren, z. B. `item` und `user`:

//// tab | Python 3.10+

```Python hl_lines="20"
{!> ../../docs_src/body_multiple_params/tutorial002_py310.py!}
```

////

//// tab | Python 3.8+

```Python hl_lines="22"
{!> ../../docs_src/body_multiple_params/tutorial002.py!}
```

////

@pytest.fixture(
    name="client",
    params=[
        pytest.param("tutorial002", marks=needs_pydanticv2),
        pytest.param("tutorial002_py39", marks=[needs_py39, needs_pydanticv2]),
        pytest.param("tutorial002_py310", marks=[needs_py310, needs_pydanticv2]),
        pytest.param("tutorial002_an", marks=needs_pydanticv2),
        pytest.param("tutorial002_an_py39", marks=[needs_py39, needs_pydanticv2]),

```Python hl_lines="9"
{!> ../../docs_src/query_params/tutorial002.py!}
```

////

//// tab | 🐍 3️⃣.1️⃣0️⃣ & 🔛

```Python hl_lines="7"
{!> ../../docs_src/query_params/tutorial002_py310.py!}
```

////

👉 💼, 🔢 🔢 `q` 🔜 📦, & 🔜 `None` 🔢.

/// check

👀 👈 **FastAPI** 🙃 🥃 👀 👈 ➡ 🔢 `item_id` ➡ 🔢 & `q` 🚫,, ⚫️ 🔢 🔢.

///

## 🔢 🔢 🆎 🛠️

Aynı şekilde, varsayılan değerlerini `None` olarak atayarak isteğe bağlı parametreler tanımlayabilirsiniz:

//// tab | Python 3.10+

```Python hl_lines="7"
{!> ../../docs_src/query_params/tutorial002_py310.py!}
```

////

//// tab | Python 3.8+

```Python hl_lines="9"
{!> ../../docs_src/query_params/tutorial002.py!}
```

////

```

////

//// tab | Python 3.10+ non-Annotated

/// tip

Prefer to use the `Annotated` version if possible.

///

```Python hl_lines="8"
{!> ../../docs_src/header_params/tutorial002_py310.py!}
```

////

//// tab | Python 3.8+ non-Annotated

/// tip

Prefer to use the `Annotated` version if possible.

///

```Python hl_lines="10"