```

该文件`__init__.py`只是一个空文件，但它告诉 Python 其中`sql_app`的所有模块（Python 文件）都是一个包。

现在让我们看看每个文件/模块的作用。

## 安装 SQLAlchemy

先下载`SQLAlchemy`所需要的依赖：

<div class="termy">

```console
$ pip install sqlalchemy

---> 100%
```

</div>

## 创建 SQLAlchemy 部件

让我们转到文件`sql_app/database.py`。

### 导入 SQLAlchemy 部件

```Python hl_lines="1-3"

---

"_We adopted the **FastAPI** library to spawn a **REST** server that can be queried to obtain **predictions**. [for Ludwig]_"

<div style="text-align: right; margin-right: 10%;">Piero Molino, Yaroslav Dudin, and Sai Sumanth Miryala - <strong>Uber</strong> <a href="https://eng.uber.com/ludwig-v0-2/" target="_blank"><small>(ref)</small></a></div>

---

---

"_We adopted the **FastAPI** library to spawn a **REST** server that can be queried to obtain **predictions**. [for Ludwig]_"

<div style="text-align: right; margin-right: 10%;">Piero Molino, Yaroslav Dudin, and Sai Sumanth Miryala - <strong>Uber</strong> <a href="https://eng.uber.com/ludwig-v0-2/" target="_blank"><small>(ref)</small></a></div>

---

---

"\_সত্যিই, আপনি যা তৈরি করেছেন তা খুব মজবুত এবং পরিপূর্ন৷ অনেক উপায়ে, আমি যা **Hug** এ করতে চেয়েছিলাম - তা কাউকে তৈরি করতে দেখে আমি সত্যিই অনুপ্রানিত৷\_"

<div style="text-align: right; margin-right: 10%;">টিমোথি ক্রসলে - <strong><a href="https://www.hug.rest/" target="_blank">Hug</a> স্রষ্টা</strong> <a href="https://news.ycombinator.com/item?id=19455465" target="_blank"><small>(ref)</small></a></div>

          python-version: "3.10"
      - name: Install build dependencies
        run: pip install build
      - name: Build source distribution
        env:
          TIANGOLO_BUILD_PACKAGE: ${{ matrix.package }}
        run: python -m build --sdist
      - name: Decompress source distribution
        run: |
          cd dist
          tar xvf fastapi*.tar.gz
      - name: Install test dependencies
        run: |

If you want to play with JWT tokens and see how they work, check <a href="https://jwt.io/" class="external-link" target="_blank">https://jwt.io</a>.

## Install `python-jose`

We need to install `python-jose` to generate and verify the JWT tokens in Python:

<div class="termy">

```console
$ pip install "python-jose[cryptography]"

---> 100%
```

</div>

You can define files and form fields at the same time using `File` and `Form`.

!!! info
    To receive uploaded files and/or form data, first install <a href="https://github.com/Kludex/python-multipart" class="external-link" target="_blank">`python-multipart`</a>.

    E.g. `pip install python-multipart`.

## Import `File` and `Form`

=== "Python 3.9+"

    ```Python hl_lines="3"

| Parameter | Type | Description |
|------------|------|-------------|
| `title` | `str` | The title of the API. |
| `summary` | `str` | A short summary of the API. <small>Available since OpenAPI 3.1.0, FastAPI 0.99.0.</small> |
| `description` | `str` | A short description of the API. It can use Markdown. |

# (2)
WORKDIR /tmp

# (3)
RUN pip install poetry

# (4)
COPY ./pyproject.toml ./poetry.lock* /tmp/

# (5)
RUN poetry export -f requirements.txt --output requirements.txt --without-hashes

# (6)
FROM python:3.9

# (7)
WORKDIR /code

# (8)
COPY --from=requirements-stage /tmp/requirements.txt /code/requirements.txt

# (9)
RUN pip install --no-cache-dir --upgrade -r /code/requirements.txt

# 表单数据

接收的不是 JSON，而是表单字段时，要使用 `Form`。

!!! info "说明"

    要使用表单，需预先安装 <a href="https://github.com/Kludex/python-multipart" class="external-link" target="_blank">`python-multipart`</a>。

    例如，`pip install python-multipart`。

## 导入 `Form`

从 `fastapi` 导入 `Form`：

```Python hl_lines="1"
{!../../../docs_src/request_forms/tutorial001.py!}
```

## 定义 `Form` 参数

创建表单（`Form`）参数的方式与 `Body` 和 `Query` 一样：