*   <li>{@code override}: Completely replaces the element</li>
 *   <li>{@code remove}: Removes the element</li>
 * </ul>
 *
 * <p>For complex XML structures, combining can also be done based on:</p>
 * <ul>
 *   <li>ID: Using the {@code combine.id} attribute</li>
 *   <li>Keys: Using the {@code combine.keys} attribute with comma-separated key names</li>
 * </ul>
 *
 * @since 4.0.0
 */

    "bar": {"id": "bar", "title": "Bar", "description": "The bartenders"},
}

app = FastAPI()


class Item(BaseModel):
    id: str
    title: str
    description: str | None = None


@app.get("/items/{item_id}", response_model=Item)
async def read_main(item_id: str, x_token: str = Header()):
    if x_token != fake_secret_token:

    "bar": {"id": "bar", "title": "Bar", "description": "The bartenders"},
}

app = FastAPI()


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


@app.get("/items/{item_id}", response_model=Item)
async def read_main(item_id: str, x_token: str = Header()):
    if x_token != fake_secret_token:

from pydantic import BaseModel, Field

app = FastAPI()


class Item(BaseModel):
    name: str
    description: str | None = Field(
        default=None, title="The description of the item", max_length=300
    )
    price: float = Field(gt=0, description="The price must be greater than zero")
    tax: float | None = None


@app.put("/items/{item_id}")
async def update_item(item_id: int, item: Item = Body(embed=True)):

from typing import Any, Union

from fastapi import FastAPI
from pydantic import BaseModel

app = FastAPI()


class Item(BaseModel):
    name: str
    description: Union[str, None] = None
    price: float
    tax: Union[float, None] = None
    tags: list[str] = []


@app.post("/items/", response_model=Item)
async def create_item(item: Item) -> Any:
    return item


@app.get("/items/", response_model=list[Item])

from typing import Annotated, Union

from fastapi import Body, FastAPI
from pydantic import BaseModel

app = FastAPI()


class Item(BaseModel):
    name: str
    description: Union[str, None] = None
    price: float
    tax: Union[float, None] = None


@app.put("/items/{item_id}")
async def update_item(
    *,
    item_id: int,
    item: Annotated[
        Item,
        Body(
            examples=[
                {

    "bar": {"id": "bar", "title": "Bar", "description": "The bartenders"},
}

app = FastAPI()


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


@app.get("/items/{item_id}", response_model=Item)
async def read_main(item_id: str, x_token: Annotated[str, Header()]):
    if x_token != fake_secret_token:

Da einfache Werte standardmäßig als Query-Parameter interpretiert werden, müssen Sie `Query` nicht explizit hinzufügen, Sie können einfach schreiben:

```Python
q: Union[str, None] = None
```

Oder in Python 3.10 und darüber:

```Python
q: str | None = None
```

Zum Beispiel:

{* ../../docs_src/body_multiple_params/tutorial004_an_py310.py hl[28] *}

/// info | Info

    assert response.json() == {
        "detail": [
            {
                "type": "missing",
                "loc": ["query", "query"],
                "msg": "Field required",
                "input": None,
            }
        ]
    }


def test_query_query_baz():
    response = client.get("/query?query=baz")
    assert response.status_code == 200
    assert response.json() == "foo bar baz"

items = {"foo": {"name": "Fighters", "size": 6}, "bar": {"name": "Tenders", "size": 3}}


@app.put("/items/{item_id}")
async def upsert_item(
    item_id: str,
    name: Annotated[Union[str, None], Body()] = None,
    size: Annotated[Union[int, None], Body()] = None,
):
    if item_id in items:
        item = items[item_id]
        item["name"] = name
        item["size"] = size
        return item
    else: