package clause

type Returning struct {
	Columns []Column
}

// Name where clause name
func (returning Returning) Name() string {
	return "RETURNING"
}

// Build build where clause
func (returning Returning) Build(builder Builder) {
	if len(returning.Columns) > 0 {
		for idx, column := range returning.Columns {
			if idx > 0 {
				builder.WriteByte(',')
			}

			builder.WriteQuoted(column)
		}
	} else {

        ) {
            assertHasErrors(
                "Method com.example.Source.foo(): From non-null returning to null returning breaking change.",
                "Method com.example.Source.getSomeVal(): From non-null returning to null returning breaking change.",
                "Method com.example.Source.getSomeVar(): From non-null returning to null returning breaking change."
            )
            assertHasWarnings(

				[]clause.Column{clause.PrimaryColumn},
			}},
			"SELECT * FROM `users` RETURNING `users`.`id`", nil,
		}, {
			[]clause.Interface{clause.Select{}, clause.From{}, clause.Returning{
				[]clause.Column{clause.PrimaryColumn},
			}, clause.Returning{
				[]clause.Column{{Name: "name"}, {Name: "age"}},
			}},
			"SELECT * FROM `users` RETURNING `users`.`id`,`name`,`age`", nil,
		},
	}

	return
}

func hasReturning(tx *gorm.DB, supportReturning bool) (bool, gorm.ScanMode) {
	if supportReturning {
		if c, ok := tx.Statement.Clauses["RETURNING"]; ok {
			returning, _ := c.Expression.(clause.Returning)
			if len(returning.Columns) == 0 || (len(returning.Columns) == 1 && returning.Columns[0].Name == "*") {
				return true, 0
			}
			return true, gorm.ScanUpdate
		}
	}
	return false, 0
}

	}
}

// only sqlite, postgres, sqlserver support returning
func TestSoftDeleteReturning(t *testing.T) {
	if DB.Dialector.Name() != "sqlite" && DB.Dialector.Name() != "postgres" && DB.Dialector.Name() != "sqlserver" {
		return
	}

	users := []*User{
		GetUser("delete-returning-1", Config{}),
		GetUser("delete-returning-2", Config{}),
		GetUser("delete-returning-3", Config{}),
	}
	DB.Create(&users)

	callbacks.RegisterDefaultCallbacks(db, &callbacks.Config{
		CreateClauses:        []string{"INSERT", "VALUES", "ON CONFLICT", "RETURNING"},
		UpdateClauses:        []string{"UPDATE", "SET", "WHERE", "RETURNING"},
		DeleteClauses:        []string{"DELETE", "FROM", "WHERE", "RETURNING"},
		LastInsertIDReversed: true,
	})

	return nil
}

func (DummyDialector) DefaultValueOf(field *schema.Field) clause.Expression {

{!../../docs_src/custom_response/tutorial004.py!}
```

In this example, the function `generate_html_response()` already generates and returns a `Response` instead of returning the HTML in a `str`.

By returning the result of calling `generate_html_response()`, you are already returning a `Response` that will override the default **FastAPI** behavior.

# Middleware

You can add middleware to **FastAPI** applications.

A "middleware" is a function that works with every **request** before it is processed by any specific *path operation*. And also with every **response** before returning it.

* It takes each **request** that comes to your application.
* It can then do something to that **request** or run any needed code.

              }
            },
            directExecutor()));
    thingToCancel[0] = serializer.submit(Callables.returning(null), directExecutor());
    results.add(thingToCancel[0]);
    // Enqueue more than enough tasks to force reentrancy.
    for (int i = 0; i < 5; i++) {
      results.add(serializer.submit(Callables.returning(null), directExecutor()));
    }

    manualExecutorTask[0].run();

////

FastAPI will use this return type to:

* **Validate** the returned data.
    * If the data is invalid (e.g. you are missing a field), it means that *your* app code is broken, not returning what it should, and it will return a server error instead of returning incorrect data. This way you and your clients can be certain that they will receive the data and the data shape expected.
* Add a **JSON Schema** for the response, in the OpenAPI *path operation*.