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How to use values and distinct on different field on Django ORM?

currently I have terms on my applications and one user can have a lot of terms registered, and my current model is like this
class Term(models.Model):
id = models.UUIDField("id", default=uuid.uuid4, editable=False, primary_key=True)
user_id = models.PositiveIntegerField("user id", default=None)
name = models.CharField()
sometimes I need to do a query to get all the users who have terms registered, so I do the following query:
Term.objects.filter(active=True)
.order_by("user_id")
.values("user_id")
.distinct()
and this is enough to solve my problems, but now I'll change my model and it will look like this:
class Term(models.Model):
id = models.UUIDField("id", default=uuid.uuid4, editable=False, primary_key=True)
user_id = models.PositiveIntegerField("user id", default=None)
name = models.CharField()
shared_with = ArrayField(models.PositiveIntegerField("id do usuario"), blank=True) # New
How you can see, I've added a new field named shared_with, that basically is a array of user ids which I want to share terms, So now I need to make a query who will return all ids who can have terms registered (shared_with included). So if i register a Term with user_id = 1 and shared_with = [2,3], my query need to return [1,2,3].
I've solved this problem today with the following code, but I think I can do this just using django ORM and one query:
users = set()
for user in (
Term.objects.filter(active=True)
.order_by("user_id")
.values("user_id")
.distinct()
):
users.add(user["user_id"])
for user in (
Term.objects.filter(active=True)
.order_by("user_id")
.values("shared_with")
):
for user_id in user["shared_with"]:
users.add(user_id)
print(users) # {1,2,3}
If someone knows how to do it and can share the knowledge, I will be grateful.

I don't recommend using the PositiveIntegerField and ArrayField as relations between tables, you can use ForeignKey and ManyToManyField instead, in your case what I understand is a user can have many Terms and a Term can be shared among many users, so the perfect solution is to add ManyToManyField in your User model
class User(AbstarctUser):
... (your fields)
terms = models.ManyToManyField(Term, related_name="users")
and Term model will be like:
class Term(models.Model):
id = models.UUIDField("id", default=uuid.uuid4, editable=False, primary_key=True)
name = models.CharField(max_length=200)
active = models.BooleanField(default=True)
... (other fields)
in that case, if you want to extract user ids with active terms, you can get it as following :
users = User.objects.filter(terms__active=True).distinct().values_list("id", flat=True)

Not able to access related model data using foreign key in Django

models.py
class products(models.Model):
name = models.CharField(max_length=100)
sku = models.CharField(max_length=50)
vendor = models.CharField(max_length=50)
brand = models.CharField(max_length=50)
price = models.FloatField()
product_status = models.BooleanField()
quantity = models.IntegerField()
def __str__(self):
return self.name
# categories
class categories(models.Model):
category_name = models.CharField(max_length=50)
parent_id = models.IntegerField()
# product categories
class product_categories(models.Model):
product = models.ForeignKey(products, on_delete=models.CASCADE)
category = models.ForeignKey(categories, on_delete=models.CASCADE)
def __str__(self):
return self.category
I can access 'category' table data(inside django shell) using
data = products.objects.all()
data.values('product_categories__category__category_name')
output: <QuerySet [{'product_categories__category__category_name': 'xxxx'}}]>
If I put this(inside django shell)
data.product_categories.category
output: 'QuerySet' object has no attribute 'product_categories'
How do I get a queryset(can be passed to html) which includes data from "categories" table along with the data of "products" table

There are a couple of issues happening here. First, data is a queryset, which is kind of like a list of objects, even though here there's just one object in the list. What you want is to get an attribute off of the item in the list, so you need something like a data.first() to get to that object before you start dotting into its attributes.
Secondly, the way Django handles reverse FK relationships requires that you refer to the FK by the standard name of, in your case, product_categories_set, OR you set your own related_name attribute on the FK. Something like:
# product categories
class product_categories(models.Model):
product = models.ForeignKey(products, on_delete=models.CASCADE, related_name='product_categories')
category = models.ForeignKey(categories, on_delete=models.CASCADE, related_name='product_categories')
def __str__(self):
return self.category
so that you can refer to your product_categories model from both the product and categories using just data.product_categories.
Thirdly, when accessing a reverse FK relationship, just like in point (1) above, you will get a related manager, from which you can get a queryset of items. Thus, to get the category name, you need to indicate which item you want the category name for. Assuming it's just the first item for everything, it would look something like:
data = products.objects.all()
product_category = data.product_categories.all()
category_name = product_category.category.category_name
Of course once you have more data, you'll not always want to just pick the first item, so you'll need to add filtering logic into the query to make sure you get the item you're looking for.
ETA, I do agree with the comment by Jorge above - a MTM would make this a bit simpler and would, in essence, create your product_categories table for you.

django filter get parent to child

i am using django(3.1.5). and i am trying to get parent model to child model by filter query
i have model like -
class Product(models.Model):
product_name = models.CharField(max_length=255, unique=True)
is_feature = models.BooleanField(default=False)
is_approved = models.BooleanField(default=False)
created_at = models.DateTimeField(auto_now_add=True)
class ProductGalleryImage(models.Model):
product = models.ForeignKey(Product, on_delete=models.CASCADE)
product_gallery_image = models.FileField(upload_to='path')
is_feature = models.BooleanField(default=False)
i am getting data from SELECT * FROM products_product AS pp INNER JOIN products_productgalleryimage AS ppgi ON ppgi.product_id = pp.id WHERE ppgi.is_feature=1 AND pp.is_feature=1 AND is_approved=1 ORDER BY pp.created_at LIMIT 4 mysql query.
so how can i get data like this query in django filter query

Firstly you can add related_name to ProductGalleryImage for better query support like this
product = models.ForeignKey(Product, on_delete=models.CASCADE, related_name='product_images')
Then your query should be like this
products=Product.objects.filter(is_approved=True, is_feature=True, product_images__is_feature=True).order_by('created_at')[:4]

You can simply loop over the other related model like so:
for product_gallery_image in product_instance.productgalleryimage_set.all():
print(product_gallery_image.product_gallery_image)
The productgalleryimage_set here is simply the related model name in lowercase with _set appended. You can change this by setting the related_name attribute on the foreign key.
Note: This will perform a query to fetch each of the product_gallery_image objects of some product instance.
If you want to get the first object only:
product_gallery_image = product_instance.productgalleryimage_set.first()
If you want to perform a join as in your example which will perform only one query you can use select_related (this will only work in forward direction for reverse direction look at prefetch_related):
product_gallery_images = ProductGalleryImage.objects.all().select_related('product')
for product_gallery_image in product_gallery_images:
print(product_gallery_image.product.product_name)
print(product_gallery_image.product_gallery_image)

Reduce the headache on database when using ModelChoiceField

please I need your help how to reduce the database call when using ModelChoiceField as it requires a queryset and I have to use it three times separately with a model that is recursively foreign key on itself, the code is below:
ModelForm code in the init function
self.fields['category'] = forms.ModelChoiceField(queryset=queryset)
self.fields['super_category'] = forms.ModelChoiceField(queryset=)
self.fields['product_type'] = forms.ModelChoiceField(queryset=)
the model class:
class Category(ProjectBaseModel, AuditLogMixin):
parent_id = models.ForeignKey('self', related_name='children', blank=True, null=True, on_delete=models.CASCADE,verbose_name=_('Parent'))
what i tried to do is collect all ids of the desired categories in array and make only one filter queryset with them like the following:
category = auction.category
super_category = category.parent_id
product_type = super_category.parent_id
ids= [category.id,super_category.id,product_type.id]
queryset = Category.objects.filter(id__in=ids)
How to proceed with that solution

Updating inherited attributes in django model objects

I have troubles updating attributes that are inherited from other tables
class AgentCategory(models.Model):
""" Agent Category """
class Meta:
verbose_name_plural = "agentcategories"
name = models.CharField(max_length=200, unique=True)
description = models.TextField(blank=True)
class Agent(models.Model):
agentcategory = models.ManyToManyField(AgentCategory,null=True)
How should i go about manually updating agentcategory in Agent model? As of now i am trying out this method, however, it does not work):
property_selected.agentcategory = "api/v1/agentcategory/3"
property_selected.save()
Any ideas? Thanks!

As Agent has ManyToManyField relation with AgentCategory.
agentcategory would contain the list of entries.
you can update its entries by,
agent_cats = AgentCategory.objects.filter(...)
property_selected.agentcategory.clear()
property_selected.agentcategory = agent_cats
property_selected.agentcategory.save()