**FastAPI**不需要你使用SQL(关系型)数据库。

但是您可以使用任何您想要的关系型数据库。

在这里，让我们看一个使用着[SQLAlchemy](https://www.sqlalchemy.org/)的示例。

您可以很容易地将SQLAlchemy支持任何数据库，像：

* PostgreSQL
* MySQL
* SQLite
* Oracle
* Microsoft SQL Server，等等其它数据库

在此示例中，我们将使用**SQLite**，因为它使用单个文件并且 在Python中具有集成支持。因此，您可以复制此示例并按原样来运行它。

稍后，对于您的产品级别的应用程序，您可能会要使用像**PostgreSQL**这样的数据库服务器。

!!! tip

E esses modelos estão compartilhando muitos dos dados e duplicando nomes e tipos de atributos.

Nós poderíamos fazer melhor.

Podemos declarar um modelo `UserBase` que serve como base para nossos outros modelos. E então podemos fazer subclasses desse modelo que herdam seus atributos (declarações de tipo, validação, etc.).

Toda conversão de dados, validação, documentação, etc. ainda funcionará normalmente.

* 📝 Add External Link: Deploy FastAPI on Ubuntu and Serve using Caddy 2 Web Server. PR [#3572](https://github.com/tiangolo/fastapi/pull/3572) by [@tiangolo](https://github.com/tiangolo).
* 📝 Add External Link, replaces #1898. PR [#3571](https://github.com/tiangolo/fastapi/pull/3571) by [@tiangolo](https://github.com/tiangolo).

### Internal

1. Copy the `main.py` file to the `/code` directory directly (without any `./app` directory).

2. Use `fastapi run` to serve your application in the single file `main.py`.

When you pass the file to `fastapi run` it will detect automatically that it is a single file and not part of a package and will know how to import it and serve your FastAPI app. 😎

## Deployment Concepts

Usados por FastAPI / Starlette:

* <a href="https://www.uvicorn.org" target="_blank"><code>uvicorn</code></a> - para o servidor que carrega e serve sua aplicação.
* <a href="https://github.com/ijl/orjson" target="_blank"><code>orjson</code></a> - Necessário se você quer utilizar `ORJSONResponse`.

```mermaid
graph LR

browser("Browser")
proxy["Proxy auf http://0.0.0.0:9999/api/v1/app"]
server["Server auf http://127.0.0.1:8000/app"]

browser --> proxy
proxy --> server
```

!!! tip "Tipp"
    Die IP `0.0.0.0` wird üblicherweise verwendet, um anzudeuten, dass das Programm alle auf diesem Computer/Server verfügbaren IPs abhört.

    )


def test_internal_server_error():
    from docs_src.dependencies.tutorial008d import app

    client = TestClient(app, raise_server_exceptions=False)
    response = client.get("/items/portal-gun")
    assert response.status_code == 500, response.text

* **Swagger UI**: served at `/docs`.
    * You can set its URL with the parameter `docs_url`.
    * You can disable it by setting `docs_url=None`.
* **ReDoc**: served at `/redoc`.
    * You can set its URL with the parameter `redoc_url`.
    * You can disable it by setting `redoc_url=None`.

For example, to set Swagger UI to be served at `/documentation` and disable ReDoc:

```Python hl_lines="3"

---

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

<span style="color: green;">INFO</span>:     Uvicorn running on http://127.0.0.1:8000 (Press CTRL+C to quit)
<span style="color: green;">INFO</span>:     Started reloader process [28720]
<span style="color: green;">INFO</span>:     Started server process [28722]
<span style="color: green;">INFO</span>:     Waiting for application startup.
<span style="color: green;">INFO</span>:     Application startup complete.
```

</div>