<img src="/img/tutorial/separate-openapi-schemas/image02.png">
</div>

This means that it will **always have a value**, it's just that sometimes the value could be `None` (or `null` in JSON).

That means that, clients using your API don't have to check if the value exists or not, they can **assume the field will always be there**, but just that in some cases it will have the default value of `None`.

    ```

!!! note
    A path parameter is always required as it has to be part of the path.

    So, you should declare it with `...` to mark it as required.

    Nevertheless, even if you declared it with `None` or set a default value, it would not affect anything, it would still be always required.

## Order the parameters as you need

!!! tip

!!! note
    Notice that most of the code is the standard `SQLAlchemy` code you would use with any framework.

    The **FastAPI** specific code is as small as always.

## ORMs

**FastAPI** works with any database and any style of library to talk to the database.

A common pattern is to use an "ORM": an "object-relational mapping" library.

### Always `raise` in Dependencies with `yield` and `except`

If you catch an exception in a dependency with `yield`, unless you are raising another `HTTPException` or similar, you should re-raise the original exception.

        code ->> function: say_hi(name="Camila")
        function ->> code: return stored result
    end
```

In the case of our dependency `get_settings()`, the function doesn't even take any arguments, so it always returns the same value.

That way, it behaves almost as if it was just a global variable. But as it uses a dependency function, then we can override it easily for testing.

          name: docs-site
          path: ./site/**

  # https://github.com/marketplace/actions/alls-green#why
  docs-all-green:  # This job does nothing and is only used for the branch protection
    if: always()
    needs:
      - build-docs
    runs-on: ubuntu-latest
    steps:
      - name: Decide whether the needed jobs succeeded or failed
        uses: re-actors/alls-green@release/v1
        with:

* `allow_headers` - A list of HTTP request headers that should be supported for cross-origin requests. Defaults to `[]`. You can use `['*']` to allow all headers. The `Accept`, `Accept-Language`, `Content-Language` and `Content-Type` headers are always allowed for <a href="https://developer.mozilla.org/en-US/docs/Web/HTTP/CORS#simple_requests" class="external-link" rel="noopener" target="_blank">simple CORS requests</a>.

A **request** body is data sent by the client to your API. A **response** body is the data your API sends to the client.

Your API almost always has to send a **response** body. But clients don't necessarily need to send **request** bodies all the time.

                    f, cloned_types=cloned_types
                )
    new_field = create_response_field(name=field.name, type_=use_type)
    new_field.has_alias = field.has_alias  # type: ignore[attr-defined]
    new_field.alias = field.alias  # type: ignore[misc]
    new_field.class_validators = field.class_validators  # type: ignore[attr-defined]
    new_field.default = field.default  # type: ignore[misc]

    ```
    """
    return params.Path(
        default=default,
        default_factory=default_factory,
        alias=alias,
        alias_priority=alias_priority,
        validation_alias=validation_alias,
        serialization_alias=serialization_alias,
        title=title,
        description=description,
        gt=gt,
        ge=ge,
        lt=lt,
        le=le,