What is the role and purpose of QuerySet objects in the Django framework?

In Django, a QuerySet object represents a lazy set of database queries that allows you to retrieve, filter, and manipulate model data. It serves as the primary interface for interacting with the database through ORM.

Main features of QuerySet:

• Lazy: the database query is executed only when necessary (e.g., during iteration or conversion to a list).
• Filtering and sorting: you can sequentially apply methods like .filter(), .exclude(), .order_by(), and others to build complex queries.
• Composition: QuerySets can be combined and reused, simplifying the code.

Example usage:

from myapp.models import Product

# Get all products with a price greater than 100
expensive_products = Product.objects.filter(price__gt=100)

# Iterate and print
for product in expensive_products:
    print(product.name, product.price)

Thus, QuerySet is a powerful tool for convenient and efficient data access in Django.