# Writing on-request filtering for related objects
**URL:** https://forum.djangoproject.com/t/writing-on-request-filtering-for-related-objects/9909
**Category:** Using Django
**Created:** [September 29, 2021, 5:02pm UTC](https://forum.djangoproject.com/t/writing-on-request-filtering-for-related-objects/9909 "2021-09-29T17:02:54Z")
**Posts on this page:** 4
**Page:** 1
### Author:  [@tragicomic](https://forum.djangoproject.com/u/tragicomic)
#### Post date: [September 29, 2021, 5:02pm UTC](https://forum.djangoproject.com/t/writing-on-request-filtering-for-related-objects/9909/1 "2021-09-29T17:02:54Z")
Suppose that we have following models
```auto
class Category(models.Model):
name = models.CharField(max_length=254)
class Item(models.Model):
category = models.ForeignKey(Category, on_delete=models.CASCADE, related_name="items")
name = models.CharField(max_length=254)
state = models.ForeignKey(State, on_delete=models.CASCADE)
```
Categories and their items are listed like so
```auto
def view(request):
categories = Category.objects.all()
pass
{% for category in categories %}
{{ category.name }}
{% for item in category.items.all %}
{{ item.name }}
{% endfor %}
{% endfor %}
```
In this structure, I want to write on-request filtering for listed ‘items’.
```auto
def view(request):
...
queryset = ???
state = request.GET.get('state')
if state:
queryset = queryset.filter(state__name=state)
```
The problem is defining ‘queryset’. Because, Items are listed as related objects of category.
Can it be done properly? or Do I need to change design?
You can take a look at my low fidelity design to be more clear.
---
### Author:  [@CodenameTim](https://forum.djangoproject.com/u/CodenameTim)
#### Post date: [September 29, 2021, 8:05pm UTC](https://forum.djangoproject.com/t/writing-on-request-filtering-for-related-objects/9909/2 "2021-09-29T20:05:55Z")
You could use a [`Prefetch`](https://docs.djangoproject.com/en/3.2/ref/models/querysets/#django.db.models.Prefetch) object. Give that a look and let me know if you have questions.
---
### Author:  [@tragicomic](https://forum.djangoproject.com/u/tragicomic)
#### Post date: [September 29, 2021, 10:02pm UTC](https://forum.djangoproject.com/t/writing-on-request-filtering-for-related-objects/9909/3 "2021-09-29T22:02:09Z")
@CodenameTim, Thank you for the reply.
Firstly, I’m trying to get queryset using [Prefetch](https://docs.djangoproject.com/en/3.2/ref/models/querysets/#django.db.models.Prefetch).
In the document, the sample is,
> ` Question.objects.prefetch_related(Prefetch('choice_set')).get().choice_set.all()`
So when I use this for me,
> `items = Category.objects.prefetch_related(Prefetch('items')).get().items.all()`
**error** : MultipleObjectsReturned → get() returned more than one Category – it returned 8!
* * *
Then, I try to use filter() instead of get()
> `items = Category.objects.prefetch_related(Prefetch('items')).filter().items.all()`
**error** : QuerySet’ object has no attribute ‘items’
How can I fix this?
---
### Author:  [@CodenameTim](https://forum.djangoproject.com/u/CodenameTim)
#### Post date: [October 4, 2021, 7:08pm UTC](https://forum.djangoproject.com/t/writing-on-request-filtering-for-related-objects/9909/4 "2021-10-04T19:08:42Z")
It sounds like there may be a misunderstanding with some other parts of the ORM. The first error, [MultipleObjectsReturned](https://docs.djangoproject.com/en/3.2/ref/models/class/#django.db.models.Model.MultipleObjectsReturned), is because [`.get()`](https://docs.djangoproject.com/en/3.2/ref/models/querysets/#get) expects one and only one value to be returned, otherwise it errors. It’s defensive mechanism of the ORM. You may be interested in the `.first()` function when you really only care about getting some value or `None` back. Please check out the ORM’s [queryset documentation](https://docs.djangoproject.com/en/3.2/ref/models/querysets/) for more extensive information.
The second error is due to attempting to access the property `items` which is does not exist on a `QuerySet` which is what’s being returned by `.filter()`. If you’re looking to explore the orm, try `.first()` to get an instance rather than `get`, but be careful of the implications.