8. Notice that this *path operation function* uses regular `def` instead of `async def`.

    As always, in FastAPI you can combine `def` and `async def` as needed.

    If you need a refresher about when to use which, check out the section _"In a hurry?"_ in the docs about [`async` and `await`](../async.md#in-a-hurry){.internal-link target=_blank}.

### ✍ 💽

🔜 ✍ 🚙 🔢 ✍ 💽.

🔁:

* ✍ 🇸🇲 🏷 *👐* ⏮️ 👆 📊.
* `add` 👈 👐 🎚 👆 💽 🎉.
* `commit` 🔀 💽 (👈 👫 🖊).
* `refresh` 👆 👐 (👈 ⚫️ 🔌 🙆 🆕 📊 ⚪️➡️ 💽, 💖 🏗 🆔).

```Python hl_lines="18-24  31-36"
{!../../../docs_src/sql_databases/sql_app/crud.py!}
```

!!! tip
    🇸🇲 🏷 `User` 🔌 `hashed_password` 👈 🔜 🔌 🔐 #️⃣ ⏬ 🔐.

Here the `app` variable will be an "instance" of the class `FastAPI`.

This will be the main point of interaction to create all your API.

### Step 3: create a *path operation*

#### Path

"Path" here refers to the last part of the URL starting from the first `/`.

So, in a URL like:

```
https://example.com/items/foo
```

...the path would be:

```
/items/foo
```

!!! info

    ```console
    $ hypercorn main:app --bind 0.0.0.0:80

    Running on 0.0.0.0:8080 over http (CTRL + C to quit)
    ```

    </div>

!!! note
    The command `uvicorn main:app` refers to:

    * `main`: the file `main.py` (the Python "module").
    * `app`: the object created inside of `main.py` with the line `app = FastAPI()`.

    It is equivalent to:

    ```Python

            dependency.

            The term "scope" comes from the OAuth2 specification, it seems to be
            intentionaly vague and interpretable. It normally refers to permissions,
            in cases to roles.

            These scopes are integrated with OpenAPI (and the API docs at `/docs`).
            So they are visible in the OpenAPI specification.
            )

* A particular program while it is **running** on the operating system.
    * This doesn't refer to the file, nor to the code, it refers **specifically** to the thing that is being **executed** and managed by the operating system.
* Any program, any code, **can only do things** when it is being **executed**. So, when there's a **process running**.

By declaring types for your variables, editors and tools can give you better support.

This is just a **quick tutorial / refresher** about Python type hints. It covers only the minimum necessary to use them with **FastAPI**... which is actually very little.

**FastAPI** is all based on these type hints, they give it many advantages and benefits.

The steps are:

* Create a SQLAlchemy model *instance* with your data.
* `add` that instance object to your database session.
* `commit` the changes to the database (so that they are saved).
* `refresh` your instance (so that it contains any new data from the database, like the generated ID).

```Python hl_lines="18-24  31-36"
{!../../../docs_src/sql_databases/sql_app/crud.py!}
```

!!! info

### Just Modern Python

It's all based on standard **Python type** declarations (thanks to Pydantic). No new syntax to learn. Just standard modern Python.

If you need a 2 minute refresher of how to use Python types (even if you don't use FastAPI), check the short tutorial: [Python Types](python-types.md){.internal-link target=_blank}.

You write standard Python with types:

```Python
from datetime import date

Next, it 🤖 takes the first task to finish (let's say, our "slow-file" 📝) and continues whatever it had to do with it.

That "wait for something else" normally refers to <abbr title="Input and Output">I/O</abbr> operations that are relatively "slow" (compared to the speed of the processor and the RAM memory), like waiting for:

* the data from the client to be sent through the network