```

1. 本例依然要从标准的 `dataclasses` 中导入 `field`；

2. 使用 `pydantic.dataclasses` 直接替换 `dataclasses`；

3. `Author` 数据类包含 `Item` 数据类列表；

4. `Author` 数据类用于 `response_model` 参数；

5. 其它带有数据类的标准类型注解也可以作为请求体；

    本例使用的是 `Item` 数据类列表；

6. 这行代码返回的是包含 `items` 的字典，`items` 是数据类列表；

    FastAPI 仍能把数据<abbr title="把数据转换为可以传输的格式">序列化</abbr>为 JSON；

7. 这行代码中，`response_model` 的类型注解是 `Author` 数据类列表；

from fastapi import FastAPI, Path
from typing_extensions import Annotated

app = FastAPI()


@app.get("/items/{item_id}")
async def read_items(
    item_id: Annotated[int, Path(title="The ID of the item to get")], q: str
):
    results = {"item_id": item_id}
    if q:
        results.update({"q": q})

from fastapi import FastAPI, Path

app = FastAPI()


@app.get("/items/{item_id}")
async def read_items(
    *,
    item_id: int = Path(title="The ID of the item to get", gt=0, le=1000),
    q: str,
):
    results = {"item_id": item_id}
    if q:
        results.update({"q": q})

                                                   styleClass="form-control">
                                            <c:forEach var="item" items="${protocolSchemeItems}">
                                                <la:option value="${f:u(item.value)}">${f:h(item.label)}</la:option>
                                            </c:forEach>
                                        </la:select>

from typing import Annotated

from fastapi import FastAPI, Path

app = FastAPI()


@app.get("/items/{item_id}")
async def read_items(
    item_id: Annotated[int, Path(title="The ID of the item to get", ge=1)], q: str
):
    results = {"item_id": item_id}
    if q:
        results.update({"q": q})

                        },
                    },
                    "summary": "Read Items",
                    "operationId": "read_items_items__item_id__put",
                    "parameters": [
                        {
                            "required": True,
                            "schema": {
                                "title": "Item Id",
                                "type": "string",

from typing import Annotated

from fastapi import FastAPI, Path

app = FastAPI()


@app.get("/items/{item_id}")
async def read_items(
    item_id: Annotated[int, Path(title="The ID of the item to get", gt=0, le=1000)],
    q: str,
):
    results = {"item_id": item_id}
    if q:
        results.update({"q": q})

```Python hl_lines="2  15  26"
{!../../docs_src/sql_databases/sql_app/models.py!}
```

🕐❔ 🔐 🔢 `items` `User`, `my_user.items`, ⚫️ 🔜 ✔️ 📇 `Item` 🇸🇲 🏷 (⚪️➡️ `items` 🏓) 👈 ✔️ 💱 🔑 ☝ 👉 ⏺ `users` 🏓.

🕐❔ 👆 🔐 `my_user.items`, 🇸🇲 🔜 🤙 🚶 & ☕ 🏬 ⚪️➡️ 💽 `items` 🏓 & 🔗 👫 📥.

& 🕐❔ 🔐 🔢 `owner` `Item`, ⚫️ 🔜 🔌 `User` 🇸🇲 🏷 ⚪️➡️ `users` 🏓. ⚫️ 🔜 ⚙️ `owner_id` 🔢/🏓 ⏮️ 🚮 💱 🔑 💭 ❔ ⏺ 🤚 ⚪️➡️ `users` 🏓.

app.mount("/static", StaticFiles(directory="static"), name="static")


templates = Jinja2Templates(directory="templates")


@app.get("/items/{id}", response_class=HTMLResponse)
async def read_item(request: Request, id: str):
    return templates.TemplateResponse(
        request=request, name="item.html", context={"id": id}

from fastapi import FastAPI, Path, Query

app = FastAPI()


@app.get("/items/{item_id}")
async def read_items(
    *,
    item_id: int = Path(title="The ID of the item to get", ge=0, le=1000),
    q: str,
    size: float = Query(gt=0, lt=10.5),
):
    results = {"item_id": item_id}
    if q:
        results.update({"q": q})
    if size:
        results.update({"size": size})