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Python | Django QuerySets
Question 1
What happens when get() is called on a queryset with no matching records, and how is this different from calling filter() when exactly one record matches?
get() returns an empty list and filter() raises DoesNotExist
get() raises a DoesNotExist error and filter() returns a queryset containing the single matching object
get() returns None and filter() raises MultipleObjectsReturned
get() runs raw SQL and filter() uses the ORM
Question 2
Which query returns posts published after a given date while keeping only records with status set to published, and which operator filters values greater than the date?
Post.objects.filter(status='published', published__gt=date) which uses gt for greater-than
Post.objects.exclude(status='draft').filter(published__lt=date) which uses lt for less-than
Post.objects.get(status='published', published__lte=date) which uses lte for less-than-or-equal
Post.objects.all().exclude(published__gte=date) which uses gte for greater-than-or-equal
Question 3
For performing an OR-based search such as finding posts where the title contains Django or the author is John, which import and filter syntax are correct?
from django.db import Q and Post.objects.filter(title__icontains='Django' | Q(author='John'))
from django import Q and Post.objects.exclude(~Q(title__icontains='Django') & Q(author='John'))
from models import Q and Post.objects.get(title__icontains='Django') or Q(author='John')
from django.db import Q and Post.objects.filter(Q(title__icontains='Django') | Q(author='John'))
Question 4
When using order_by('created') on a comments queryset, what is the default sort direction and how can this relate to query efficiency?
Ascending and always causes a full table scan
Descending and requires reverse() for ascending
Ascending which shows oldest first and can use an index on the field for efficient sorting
Random with no index impact
Question 5
When sorting products by price in descending order and then by name in ascending order for consistent tie handling, which order_by call is correct?
Product.objects.order_by('-price', 'name') which applies name as the secondary sort
Product.objects.order_by('name', '-price') which prioritizes name instead of price
Product.objects.order_by('price').reverse('name') which is not valid usage
Product.objects.order_by('-price' + 'name') which treats the fields as a single string
Question 6
For a view that first orders posts by date in ascending order, which method reverses that ordering without rewriting the order_by call, and why is using -date directly often better for large datasets?
Post.objects.filter(published=True).reverse('date') which treats the argument as a lookup and is invalid
Post.objects.order_by('date').exclude(reverse=True) which does nothing related to reversing
Post.objects.reverse().order_by('date') which reverses before ordering and produces inefficient, unpredictable results
Post.objects.order_by('date').reverse() which flips the order and using -date directly is faster because the database can sort once without an extra reversal step
There are 6 questions to complete.