<img src="/img/tutorial/generate-clients/image08.png">

## Benefits

When using the automatically generated clients you would get **autocompletion** for:

* Methods.
* Request payloads in the body, query parameters, etc.
* Response payloads.

You would also have **inline errors** for everything.

    You don't need to see the code in `./scripts/docs.py`, you just use it in the command line.

All the documentation is in Markdown format in the directory `./docs/en/`.

Many of the tutorials have blocks of code.

In most of the cases, these blocks of code are actual complete applications that can be run as is.

In fact, those blocks of code are not written inside the Markdown, they are Python files in the `./docs_src/` directory.

Die Abhängigkeiten funktionieren weiterhin wie erwartet, und das **Beste daran** ist, dass die **Typinformationen erhalten bleiben**, was bedeutet, dass Ihr Editor Ihnen weiterhin **automatische Vervollständigung**, **Inline-Fehler**, usw. bieten kann. Das Gleiche gilt für andere Tools wie `mypy`.

The way it works is that you write the definition of the schema using YAML format inside the docstring of each function handling a route.

And it generates OpenAPI schemas.

That's how it works in Flask, Starlette, Responder, etc.

But then, we have again the problem of having a micro-syntax, inside of a Python string (a big YAML).

Bạn viết chuẩn Python với kiểu dữ liệu như sau:

```Python
from datetime import date

from pydantic import BaseModel

# Declare a variable as a str
# and get editor support inside the function
def main(user_id: str):
    return user_id


# A Pydantic model
class User(BaseModel):
    id: int
    name: str
    joined: date
```

Sau đó có thể được sử dụng:

```Python

```

...并根据您的数据库数据和相关凭据（也适用于 MySQL、MariaDB 或任何其他）对其进行调整。

!!! tip

    如果您想使用不同的数据库，这是就是您必须修改的地方。

### 创建 SQLAlchemy 引擎

第一步，创建一个 SQLAlchemy的“引擎”。

我们稍后会将这个`engine`在其他地方使用。

```Python hl_lines="8-10"
{!../../../docs_src/sql_databases/sql_app/database.py!}
```

#### 注意

参数:

```Python
connect_args={"check_same_thread": False}
```

<img src="/img/tutorial/generate-clients/image08.png">

## Vorteile

Wenn Sie die automatisch generierten Clients verwenden, erhalten Sie **automatische Codevervollständigung** für:

* Methoden.
* Request-Payloads im Body, Query-Parameter, usw.
* Response-Payloads.

Außerdem erhalten Sie für alles **Inline-Fehlerberichte**.

```Python hl_lines="10-11" title="app/main.py"
{!../../../docs_src/bigger_applications/app/main.py!}
```

!!! info
    `users.router` contains the `APIRouter` inside of the file `app/routers/users.py`.

    And `items.router` contains the `APIRouter` inside of the file `app/routers/items.py`.

With `app.include_router()` we can add each `APIRouter` to the main `FastAPI` application.

#### Union

You can declare that a variable can be any of **several types**, for example, an `int` or a `str`.

In Python 3.6 and above (including Python 3.10) you can use the `Union` type from `typing` and put inside the square brackets the possible types to accept.

Quando você usa o _script_ em `./scripts/docs.py` com o comando `live` ele somente exibe os arquivos e traduções disponíveis para a linguagem atual.

Mas uma vez que você tenha concluído, você poderá testar tudo como se parecesse _online_.

Para fazer isso, primeiro construa toda a documentação:

<div class="termy">

```console
// Use o comando "build-all", isso leverá um tempinho
$ python ./scripts/docs.py build-all

Updating es