```

#### 注意

参数:

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

...仅用于`SQLite`，在其他数据库不需要它。

!!! info "技术细节"

    默认情况下，SQLite 只允许一个线程与其通信，假设有多个线程的话，也只将处理一个独立的请求。

    这是为了防止意外地为不同的事物（不同的请求）共享相同的连接。

    但是在 FastAPI 中，普遍使用def函数，多个线程可以为同一个请求与数据库交互，所以我们需要使用`connect_args={"check_same_thread": False}`来让SQLite允许这样。

```

#### 🗒

❌:

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

...💪 🕴 `SQLite`. ⚫️ 🚫 💪 🎏 💽.

!!! info "📡 ℹ"

    🔢 🗄 🔜 🕴 ✔ 1️⃣ 🧵 🔗 ⏮️ ⚫️, 🤔 👈 🔠 🧵 🔜 🍵 🔬 📨.

    👉 ❎ 😫 🤝 🎏 🔗 🎏 👜 (🎏 📨).

    ✋️ FastAPI, ⚙️ 😐 🔢 (`def`) 🌅 🌘 1️⃣ 🧵 💪 🔗 ⏮️ 💽 🎏 📨, 👥 💪 ⚒ 🗄 💭 👈 ⚫️ 🔜 ✔ 👈 ⏮️ `connect_args={"check_same_thread": False}`.

### Connect and disconnect in the dependency `get_db()`

Then the next question would be, why not just connect and disconnect the database in the `async` dependency itself, instead of in `get_db()`?

There you can select "Releases only".

By doing it, you will receive notifications (in your email) whenever there's a new release (a new version) of **FastAPI** with bug fixes and new features.

## Connect with the author

You can connect with <a href="https://tiangolo.com" class="external-link" target="_blank">me (Sebastián Ramírez / `tiangolo`)</a>, the author.

You can:

# TODO: import from typing when deprecating Python 3.9
from typing_extensions import Annotated, Doc


class OAuth2PasswordRequestForm:
    """
    This is a dependency class to collect the `username` and `password` as form data
    for an OAuth2 password flow.

    The OAuth2 specification dictates that for a password flow the data should be

* `fixedquery` : a pour valeur exacte `fixedquery`.
* `$` : se termine directement ensuite, n'a pas d'autres caractères après `fixedquery`.

Si vous vous sentez perdu avec le concept d'**expression régulière**, pas d'inquiétudes. Il s'agit d'une notion difficile pour beaucoup, et l'on peut déjà réussir à faire beaucoup sans jamais avoir à les manipuler.

We will later use this `engine` in other places.

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

#### Note

The argument:

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

...is needed only for `SQLite`. It's not needed for other databases.

!!! info "Technical Details"

<mxfile host="65bd71144e">
    <diagram id="BkDNbdtn8_9fWQybnc8v" name="Page-1">
        <mxGraphModel dx="741" dy="1167" grid="1" gridSize="10" guides="1" tooltips="1" connect="1" arrows="1" fold="1" page="1" pageScale="1" pageWidth="1920" pageHeight="1200" math="0" shadow="0">
            <root>
                <mxCell id="0"/>
                <mxCell id="1" parent="0"/>

    In that case, you wouldn't have to worry about any of this. 🤷

### Examples of Previous Steps Strategies

This will **depend heavily** on the way you **deploy your system**, and it would probably be connected to the way you start programs, handling restarts, etc.

Here are some possible ideas:

* An "Init Container" in Kubernetes that runs before your app container

* A encriptação da conexão acontece no nível TCP.
    * TCP é uma camada abaixo do HTTP.
    * Então, o controle de certificado e encriptação é feito antes do HTTP.
* TCP não conhece nada sobre "domínios". Somente sobre endereços IP.
    * A informação sobre o domínio requisitado vai nos dados HTTP.