```

!!! tip
    You could reduce duplication in that code by putting it in a function and using it from both `database.py` and `tests/test_sql_app.py`.

    For simplicity and to focus on the specific testing code, we are just copying it.

## Create the database

Because now we are going to use a new database in a new file, we need to make sure we create the database with:

```Python

But then, the project's focus shifted.

It was no longer an API web framework, as the creator needed to focus on Starlette.

Now APIStar is a set of tools to validate OpenAPI specifications, not a web framework.

!!! info

    {!> ../../../docs_src/dependencies/tutorial005.py!}
    ```

It declares an optional query parameter `q` as a `str`, and then it just returns it.

This is quite simple (not very useful), but will help us focus on how the sub-dependencies work.

## Second dependency, "dependable" and "dependant"

## First Steps

Let's see a very simple example. It will be so simple that it is not very useful, for now.

But this way we can focus on how the **Dependency Injection** system works.

### Create a dependency, or "dependable"

Let's first focus on the dependency.

It is just a function that can take all the same parameters that a *path operation function* can take:

=== "Python 3.10+"

!!! tip
    This Domain Name part is way before HTTPS, but as everything depends on the domain and the IP address, it's worth mentioning it here.

### DNS

Now let's focus on all the actual HTTPS parts.

First, the browser would check with the **DNS servers** what is the **IP for the domain**, in this case, `someapp.example.com`.

This, of course, is not optimal and you wouldn't use it for production.

In production you would have one of the options above.

But it's the simplest way to focus on the server-side of WebSockets and have a working example:

```Python hl_lines="2  6-38  41-43"
{!../../../docs_src/websockets/tutorial001.py!}
```

## Create a `websocket`

    So let's focus on the main cases, where it could crash entirely in some particular cases **in the future**, and it still makes sense to restart it.

* If the PR can be simplified in a way, you can ask for that, but there's no need to be too picky, there might be a lot of subjective points of view (and I will have my own as well 🙈), so it's better if you can focus on the fundamental things.

### Tests

* Help me check that the PR has **tests**.

* Check that the tests **fail** before the PR. 🚨

* Then check that the tests **pass** after the PR. ✅

!!! tip
    In the next chapter, you will see a real secure implementation, with password hashing and <abbr title="JSON Web Tokens">JWT</abbr> tokens.

    But for now, let's focus on the specific details we need.

=== "Python 3.10+"

    ```Python hl_lines="87"
    {!> ../../../docs_src/security/tutorial003_an_py310.py!}
    ```

=== "Python 3.9+"

We are going to create the same application as in the SQLAlchemy tutorial ([SQL (Relational) Databases](../tutorial/sql-databases.md){.internal-link target=_blank}).

Most of the code is actually the same.

So, we are going to focus only on the differences.

## File structure

Let's say you have a directory named `my_super_project` that contains a sub-directory called `sql_app` with a structure like this:

```
.
└── sql_app