#
# If foreign key does not exist in your database,
# you can set up here as virtual foreign key for DBFlute.
#
# And it's one-to-one relation if you add one fixed condition to referrer table, 
# you can set virtual foreign key with fixedCondition and fixedSuffix.
# And you can use it to view objects too.
#
# If local column name is same as foreign column name,
# you can omit the setting of localColumnName and foreignColumnName.

We could do better.

We can declare a `UserBase` model that serves as a base for our other models. And then we can make subclasses of that model that inherit its attributes (type declarations, validation, etc).

All the data conversion, validation, documentation, etc. will still work as normally.

///

## Await for messages and send messages { #await-for-messages-and-send-messages }

In your WebSocket route you can `await` for messages and send messages.

{* ../../docs_src/websockets_/tutorial001_py310.py hl[48:52] *}

You can receive and send binary, text, and JSON data.

## Try it { #try-it }

Put your code in a file `main.py` and then run your application:

<div class="termy">

// Singleton contains a pointer to T that must be set once.
// Until the value is set all Get() calls will block.
type Singleton[T any] struct {
	v   *T
	set chan struct{}
}

// NewSingleton creates a new unset singleton.
func NewSingleton[T any]() *Singleton[T] {
	return &Singleton[T]{set: make(chan struct{}), v: nil}
}

// Get will return the singleton value.
func (s *Singleton[T]) Get() *T {
	<-s.set
	return s.v
}

Go 1.24 changed the behavior of `go test -json` to emit build errors as JSON
instead of text.
These new JSON events are distinguished by new `Action` values,
but can still cause problems with CI systems that aren't robust to these events.
This behavior can be controlled with the `gotestjsonbuildtext` setting.
Using `gotestjsonbuildtext=1` restores the 1.23 behavior.
This setting will be removed in a future release, Go 1.28 at the earliest.

We can **read** `Hero`s from the database using a `select()`. We can include a `limit` and `offset` to paginate the results.

{* ../../docs_src/sql_databases/tutorial001_an_py310.py ln[48:55] hl[51:52,54] *}

### Read One Hero { #read-one-hero }

We can **read** a single `Hero`.

{* ../../docs_src/sql_databases/tutorial001_an_py310.py ln[58:63] hl[60] *}

### Delete a Hero { #delete-a-hero }

When you need `lifespan` to run in your tests, you can use the `TestClient` with a `with` statement:

{* ../../docs_src/app_testing/tutorial004_py310.py hl[9:15,18,27:28,30:32,41:43] *}


You can read more details about the ["Running lifespan in tests in the official Starlette documentation site."](https://www.starlette.dev/lifespan/#running-lifespan-in-tests)

For the deprecated `startup` and `shutdown` events, you can use the `TestClient` as follows:

// Copyright 2015 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.

/*
Asm, typically invoked as “go tool asm”, assembles the source file into an object
file named for the basename of the argument source file with a .o suffix. The
object file can then be combined with other objects into a package archive.

# Command Line

Usage:

	go tool asm [flags] file

* Processing data:
    * For example, let's say you receive a file that must go through a slow process, you can return a response of "Accepted" (HTTP 202) and process the file in the background.

## Using `BackgroundTasks` { #using-backgroundtasks }

Your API now has the power to control its own <dfn title="This is a joke, just in case. It has nothing to do with cookie consents, but it's funny that even the API can now reject the poor cookies. Have a cookie. 🍪">cookie consent</dfn>. 🤪🍪

You can use Pydantic's model configuration to `forbid` any `extra` fields:

{* ../../docs_src/cookie_param_models/tutorial002_an_py310.py hl[10] *}