Search and ordering in Django - Practice Problems & Coding Challenges

Challenge - 5 Problems

❓ component_behavior

intermediate

What is the output of this Django queryset ordering?

Given the model Book with fields title and published_date, what will be the order of titles returned by this queryset?

Book.objects.order_by('-published_date', 'title').values_list('title', flat=True)

Django

Assume the database has these books:<br>- 'Alpha' published 2020-01-01<br>- 'Beta' published 2021-01-01<br>- 'Gamma' published 2021-01-01

A ['Beta', 'Gamma', 'Alpha']

B ['Gamma', 'Beta', 'Alpha']

C ['Alpha', 'Beta', 'Gamma']

D ['Alpha', 'Gamma', 'Beta']

💡 Hint

Ordering first by published_date descending, then by title ascending.

The queryset orders books first by published_date descending, so 2021 books come first. Among those with the same date, titles are ordered ascending alphabetically. So 'Beta' comes before 'Gamma'.

📝 Syntax

intermediate

Which option correctly filters and orders a queryset by a search term in Django?

You want to find all Product objects whose name contains 'phone' (case-insensitive) and order them by price ascending. Which queryset is correct?

A Product.objects.filter(name__icontains='phone').order_by('-price')

B Product.objects.filter(name__contains='phone').order_by('-price')

C Product.objects.filter(name__icontains='phone').order_by('price')

D Product.objects.filter(name__contains='phone').order_by('price')

💡 Hint

Use case-insensitive contains and ascending order.

Option C uses icontains for case-insensitive search and orders by price ascending. Others either use case-sensitive filter or wrong order direction.

🔧 Debug

advanced

Why does this Django queryset raise a FieldError?

Consider this queryset:
Entry.objects.order_by('author__name')
Given Entry has a ForeignKey to Author model, why does this raise FieldError?

A Because ordering by related fields requires the related field to be in Meta.ordering

B Because ForeignKey fields cannot be used in order_by

C Because 'author__name' is a valid field and should not raise an error

D Because 'author__name' is not a valid field for ordering without using select_related()

💡 Hint

Ordering by related fields needs proper query setup.

Ordering by a related field like 'author__name' requires Django to join the related table. Without select_related(), Django may raise FieldError if the join is missing or ambiguous.

🧠 Conceptual

advanced

What is the effect of using distinct() after order_by() in a Django queryset?

Given a queryset:
MyModel.objects.order_by('category').distinct('category')
What does this do?

A Returns all records ordered by category, ignoring duplicates

B Returns one unique record per category, ordered by category ascending

C Raises a NotSupportedError because distinct with fields is not supported on all databases

D Returns records ordered by category but distinct() has no effect

💡 Hint

distinct() with fields returns unique rows by those fields.

Using distinct('category') returns one record per unique category, ordered by category ascending. However, this is only supported on PostgreSQL and may raise errors on other databases.

❓ state_output

expert

What is the output of this Django search and ordering code snippet?

Given the model Article with fields title and views, and these records:
- 'Django Tips', views=100
- 'Python Tricks', views=150
- 'Django Advanced', views=100

What does this code output?

qs = Article.objects.filter(title__icontains='django').order_by('-views', 'title').values_list('title', flat=True)
list(qs)

A ['Django Advanced', 'Django Tips']

B ['Django Tips', 'Django Advanced']

C ['Python Tricks', 'Django Tips', 'Django Advanced']

D ['Django Tips']

💡 Hint

Filter by 'django' in title, order by views descending, then title ascending.

Filter keeps 'Django Tips' and 'Django Advanced'. Both have 100 views, so ordering by -views keeps them equal, then title ascending orders 'Django Advanced' before 'Django Tips'.