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---
title: Defining Types
---
# Defining Types
## Output types
> [!NOTE]
> It is highly recommended to enable the [Query Optimizer Extension](optimizer.md)
> for improved performance and avoid some common pitfalls (e.g. the `n+1` issue)
Output types are generated from models. The `auto` type is used for field type auto resolution.
Relational fields are described by referencing to other types generated from Django models.
A many-to-many relation is described with the `typing.List` type annotation.
`strawberry_django` will automatically generate resolvers for relational fields.
More information about that can be read from [resolvers](resolvers.md) page.
```python title="types.py"
import strawberry_django
from strawberry import auto
@strawberry_django.type(models.Fruit)
class Fruit:
id: auto
name: auto
color: "Color"
@strawberry_django.type(models.Color)
class Color:
id: auto
name: auto
fruits: list[Fruit]
```
## Input types
Input types can be generated from Django models using the `strawberry_django.input` decorator.
The first parameter is the model which the type is derived from.
```python title="types.py"
@strawberry_django.input(models.Fruit)
class FruitInput:
id: auto
name: auto
color: "ColorInput"
```
A partial input type, in which all `auto`-typed fields are optional, is generated by setting the `partial` keyword argument in `input` to `True`.
Partial input types can be generated from existing input types through class inheritance.
Non-`auto` type annotations will be respected—and therefore required—unless explicitly marked `Optional[]`.
```python title="types.py"
@strawberry_django.input(models.Color, partial=True)
class FruitPartialInput(FruitInput):
color: list["ColorPartialInput"]
# Auto fields are optional
@strawberry_django.input(models.Color, partial=True)
class ColorPartialInput:
id: auto
name: auto
fruits: list[FruitPartialInput]
# Alternate input; "name" field will be required
@strawberry_django.input(models.Color, partial=True)
class ColorNameRequiredPartialInput:
id: auto
name: str
fruits: list[FruitPartialInput]
```
## Types from Django models
Django models can be converted to `strawberry` Types with the `strawberry_django.type` decorator. Custom descriptions can be added using the `description` keyword argument (See: [`strawberry.type` decorator API](https://strawberry.rocks/docs/types/object-types#api)).
```python title="types.py"
import strawberry_django
@strawberry_django.type(models.Fruit, description="A tasty snack")
class Fruit:
...
```
### Adding fields to the type
By default, no fields are implemented on the new type. Check the documentation
on [How to define Fields](fields.md) for that.
### Customizing the returned `QuerySet`
> [!WARNING]
> By doing this you are modifying all automatic `QuerySet` generation for any field
> that returns this type. Ideally you will want to define your own [resolver](resolvers.md)
> instead, which gives you more control over it.
By default, a `strawberry_django` type will get data from the default manager for its Django Model.
You can implement a custom `get_queryset` classmethod to your type to do some extra processing to the default queryset,
like filtering it further.
```python title="types.py"
@strawberry_django.type(models.Fruit)
class Berry:
@classmethod
def get_queryset(cls, queryset, info, **kwargs):
return queryset.filter(name__contains="berry")
```
The `get_queryset` classmethod is given a `QuerySet` to filter and
a `strawberry` `Info` object containing details about the request.
You can use that `info` parameter to, for example,
limit access to results based on the current user in the request:
```python title="types.py"
from strawberry_django.auth.utils import get_current_user
@strawberry_django.type(models.Fruit)
class Berry:
@classmethod
def get_queryset(cls, queryset, info, **kwargs):
user = get_current_user(info)
if not user.is_staff:
# Restrict access to top secret berries if the user is not a staff member
queryset = queryset.filter(is_top_secret=False)
return queryset.filter(name__contains="berry")
```
> [!NOTE]
> Another way of limiting this is by using the [PermissionExtension](permissions.md)
> provided by this lib.
The `kwargs` dictionary can include other parameters that were added in a `@strawberry.django.type` definition
like [filters](filters.md) or [pagination](pagination.md).
|
