select_related_sample.py

# Hits the database.
product = Product.objects.get(id=10)

# Hits the database again to get the related Category object.
category = product.category


# using select_related
# Hits the database
product = Product.objects.select_related('category').get(id=10)

# Doesn't hit the database because Category obj is already fetched in the above query.
category = product.category