And `threading.local` is not compatible with the new async features of modern Python.

!!! note "Technical Details"
    `threading.local` is used to have a "magic" variable that has a different value for each thread.

    This was useful in older frameworks designed to have one single thread per request, no more, no less.

!!! tip
    The important and "magic" thing here is that `get_current_user` will have a different list of `scopes` to check for each *path operation*.

{!../../../docs_src/sql_databases/sql_app/models.py!}
```

### Create the relationships

Now create the relationships.

For this, we use `relationship` provided by SQLAlchemy ORM.

This will become, more or less, a "magic" attribute that will contain the values from other tables related to this one.

```Python hl_lines="2  15  26"
{!../../../docs_src/sql_databases/sql_app/models.py!}
```