!!! note
    FastAPI will know that the value of `q` is not required because of the default value `= None`.

    The `Union` in `Union[str, None]` will allow your editor to give you better support and detect errors.

## Additional validation

We are going to enforce that even though `q` is optional, whenever it is provided, **its length doesn't exceed 50 characters**.

    * **Schnell**: Sehr hohe Leistung, auf Augenhöhe mit **NodeJS** und **Go** (dank Starlette und Pydantic).
    * **Intuitiv**: Hervorragende Editor-Unterstützung. <abbr title="Auch bekannt als automatische Vervollständigung, IntelliSense">Codevervollständigung</abbr> überall. Weniger Zeitaufwand für das Debuggen.

...de:

```Python
        ... "item_name": item.name ...
```

...a:

```Python
        ... "item_price": item.price ...
```

... y mira como el editor va a auto-completar los atributos y sabrá sus tipos:

![soporte de editor](https://fastapi.tiangolo.com/img/vscode-completion.png)

And then, when using the dependency in a *path operation function*, we declare it with the type `Session` we imported directly from SQLAlchemy.

This will then give us better editor support inside the *path operation function*, because the editor will know that the `db` parameter is of type `Session`:

=== "Python 3.9+"

    ```Python hl_lines="22  30  36  45  51"
    {!> ../../../docs_src/sql_databases/sql_app_py39/main.py!}

!!! note "Hinweis"
    FastAPI weiß nur dank des definierten Defaultwertes `=None`, dass der Wert von `q` nicht erforderlich ist

    `Union[str, None]` hingegen erlaubt ihren Editor, Sie besser zu unterstützen und Fehler zu erkennen.

## Zusätzliche Validierung

Wir werden bewirken, dass, obwohl `q` optional ist, wenn es gegeben ist, **seine Länge 50 Zeichen nicht überschreitet**.

##  **FastAPI** tip belirteçleri

**FastAPI** birkaç şey yapmak için bu tür tip belirteçlerinden faydalanır.

**FastAPI** ile parametre tiplerini bildirirsiniz ve şunları elde edersiniz:

* **Editor desteği**.
* **Tip kontrolü**.

...ve **FastAPI** aynı belirteçleri şunlar için de kullanıyor:

  // RFC-6335 and https://www.iana.org/assignments/service-names).
  //
  // * Kubernetes-defined prefixed names:
  //   * 'kubernetes.io/h2c' - HTTP/2 over cleartext as described in https://www.rfc-editor.org/rfc/rfc7540
  //
  // * Other protocols should use implementation-defined prefixed names such as
  // mycompany.com/my-custom-protocol.
  // +optional
  optional string appProtocol = 4;
}

    # XXX: if you enable this setting, unparam will report a lot of false-positives in text editors:
    # if it's called for subdir of a project it can't find external interfaces. All text editor integrations
    # with golangci-lint call it on a directory with the changed file.
    check-exported: false
  gci:
    sections:

    link: https://fullstackstation.com/fastapi-trien-khai-bang-docker/
    title: 'FASTAPI: TRIỂN KHAI BẰNG DOCKER'
  Taiwanese:
  - author: Leon
    author_link: http://editor.leonh.space/
    link: https://editor.leonh.space/2022/tortoise/
    title: 'Tortoise ORM / FastAPI 整合快速筆記'
Podcasts:
  English:
  - author: Real Python
    author_link: https://realpython.com/

IMG="${IMG:-${TOOLS_REGISTRY_PROVIDER}/${PROJECT_ID}/${IMAGE_NAME}:${IMAGE_VERSION}}"

CONTAINER_CLI="${CONTAINER_CLI:-docker}"

ENV_BLOCKLIST="${ENV_BLOCKLIST:-^_\|^PATH=\|^GOPATH=\|^GOROOT=\|^SHELL=\|^EDITOR=\|^TMUX=\|^USER=\|^HOME=\|^PWD=\|^TERM=\|^RUBY_\|^GEM_\|^rvm_\|^SSH=\|^TMPDIR=\|^CC=\|^CXX=\|^MAKEFILE_LIST=}"

# Remove functions from the list of exported variables, they mess up with the `env` command.