# Query Parameter Models

If you have a group of **query parameters** that are related, you can create a **Pydantic model** to declare them.

This would allow you to **re-use the model** in **multiple places** and also to declare validations and metadata for all the parameters at once. 😎

/// note

This is supported since FastAPI version `0.115.0`. 🤓

///

## Query Parameters with a Pydantic Model

# Extra Models

Continuing with the previous example, it will be common to have more than one related model.

This is especially the case for user models, because:

* The **input model** needs to be able to have a password.
* The **output model** should not have a password.
* The **database model** would probably need to have a hashed password.

/// danger

Never store user's plaintext passwords. Always store a "secure hash" that you can then verify.

////

O **FastAPI** irá **extrair** as informações para **cada campo** dos **dados do formulário** na requisição e dar para você o modelo Pydantic que você definiu.

## Confira os Documentos

Você pode verificar na UI de documentação em `/docs`:

<div class="screenshot">
<img src="/img/tutorial/request-form-models/image01.png">
</div>

## Proibir Campos Extras de Formulários

from fastapi import FastAPI
from fastapi.testclient import TestClient
from pydantic import BaseModel

app = FastAPI()


class Model(BaseModel):
    pass


class Model2(BaseModel):
    a: Model


class Model3(BaseModel):
    c: Model
    d: Model2


@app.get("/", response_model=Model3)
def f():
    return {"c": {}, "d": {"a": {}}}


client = TestClient(app)


def test_get_api_route():

Zum Beispiel könnten Sie **ein Dict zurückgeben** wollen, oder ein Datenbank-Objekt, aber **es als Pydantic-Modell deklarieren**. Auf diese Weise übernimmt das Pydantic-Modell alle Datendokumentation, -validierung, usw. für das Objekt, welches Sie zurückgeben (z. B. ein Dict oder ein Datenbank-Objekt).

# OpenAPI `models`

OpenAPI Pydantic models used to generate and validate the generated OpenAPI.

# Modelos de Parâmetros de Cookie

Se você possui um grupo de **cookies** que estão relacionados, você pode criar um **modelo Pydantic** para declará-los. 🍪

Isso lhe permitiria **reutilizar o modelo** em **diversos lugares** e também declarar validações e metadata para todos os parâmetros de uma vez. 😎

/// note | Nota

Isso é suportado desde a versão `0.115.0` do FastAPI. 🤓

///

/// tip | Dica

# Cookie Parameter Models

If you have a group of **cookies** that are related, you can create a **Pydantic model** to declare them. 🍪

This would allow you to **re-use the model** in **multiple places** and also to declare validations and metadata for all the parameters at once. 😎

/// note

This is supported since FastAPI version `0.115.0`. 🤓

///

/// tip

This same technique applies to `Query`, `Cookie`, and `Header`. 😎

///

Aber dieser Typ kann selbst ein anderes Pydantic-Modell sein.

Sie können also tief verschachtelte JSON-„Objekte“ deklarieren, mit spezifischen Attributnamen, -typen, und -validierungen.

Alles das beliebig tief verschachtelt.

### Ein Kindmodell definieren

Wir können zum Beispiel ein `Image`-Modell definieren.

//// tab | Python 3.10+

```Python hl_lines="7-9"

## Nested Models

Each attribute of a Pydantic model has a type.

But that type can itself be another Pydantic model.

So, you can declare deeply nested JSON "objects" with specific attribute names, types and validations.

All that, arbitrarily nested.

### Define a submodel

For example, we can define an `Image` model:

//// tab | Python 3.10+