Snippet

Custom Model Manager Method Returning Flattened List Collections

Custom QuerySets encapsulate data retrieval patterns into reusable methods. Using `.values_list('sku', flat=True)` flattens single-column database queries directly into standard Python lists.

snippet.py

python

from django.db import models
 
class ProductQuerySet(models.QuerySet):
    def extract_active_sku_list(self) -> list[str]:
        return list(
            self.filter(is_active=True)
            .values_list("sku", flat=True)
            .distinct()
        )
 
class Product(models.Model):
    sku = models.CharField(max_length=30, unique=True)
    is_active = models.BooleanField(default=True)
    objects = ProductQuerySet.as_manager()

django

Breakdown

class ProductQuerySet(models.QuerySet):

Defines a custom QuerySet subclass to encapsulate reusable domain queries.

def extract_active_sku_list(self) -> list[str]:

Defines a manager method returning a typed list of SKU strings.

.values_list("sku", flat=True)

Retrieves values as single flat tuples/list items instead of tuple objects.

objects = ProductQuerySet.as_manager()

Attaches the custom QuerySet methods directly to the Django Model manager.

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Custom Model Manager Method Returning Flattened List Collections

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