DetailView for single objects in Django - Practice Problems & Coding Challenges

Challenge - 5 Problems

❓ component_behavior

intermediate

What does this Django DetailView render?

Given this DetailView and URL pattern, what will the template receive as context variable?

Django

from django.views.generic.detail import DetailView
from .models import Book

class BookDetailView(DetailView):
    model = Book
    template_name = 'books/detail.html'

# URL pattern:
# path('books/<int:pk>/', BookDetailView.as_view(), name='book-detail')

A No context variable is passed to the template

B A context variable named 'object_list' containing all Book instances

C A context variable named 'book_detail' containing the Book instance with the given pk

D A context variable named 'book' containing the Book instance with the given pk

💡 Hint

Think about the default context variable name DetailView uses for the model instance.

The DetailView automatically passes the single object as a context variable named after the model in lowercase. Here, it is 'book'.

📝 Syntax

intermediate

Which option correctly overrides get_object in a DetailView?

You want to customize how the object is fetched in a DetailView. Which code snippet correctly overrides get_object?

Django

from django.views.generic.detail import DetailView
from .models import Author

class AuthorDetailView(DetailView):
    model = Author
    def get_object(self):
        # custom logic here
        pass

A

def get_object(self):
    return Author.objects.filter(pk=self.kwargs['pk'])

B

def get_object(self):
    return Author.objects.get(pk=self.kwargs['pk'])

C

def get_object(self):
    return self.model.objects.get(id=self.request.GET['id'])

D

def get_object(self):
    return self.model.get(pk=self.kwargs['pk'])

💡 Hint

Remember get_object should return a single model instance, not a queryset.

Option B correctly uses get() with pk from kwargs. Option B uses GET parameters incorrectly. Option B returns a queryset, not an object. Option B calls get on the model class incorrectly.

❓ state_output

advanced

What is the output of this DetailView with missing pk in URL?

Consider this DetailView and URL pattern. What happens if you visit '/authors/' without a pk?

Django

from django.views.generic.detail import DetailView
from .models import Author

class AuthorDetailView(DetailView):
    model = Author

# URL pattern:
# path('authors/<int:pk>/', AuthorDetailView.as_view(), name='author-detail')

A 404 Not Found error is raised

B The first Author object is shown by default

C A TypeError is raised because pk is missing

D The view redirects to the authors list page

💡 Hint

Think about what happens when the URL does not provide the required pk argument.

The URL pattern requires a pk. Without it, Django cannot resolve the URL to this view, so a 404 error occurs.

🔧 Debug

advanced

Why does this DetailView raise MultipleObjectsReturned error?

This DetailView code raises MultipleObjectsReturned. Why?

Django

from django.views.generic.detail import DetailView
from .models import Publisher

class PublisherDetailView(DetailView):
    model = Publisher
    def get_object(self):
        return Publisher.objects.get(name=self.kwargs['name'])

# URL pattern:
# path('publishers/<str:name>/', PublisherDetailView.as_view(), name='publisher-detail')

A The model Publisher does not have a 'name' field

B The URL pattern does not pass 'name' to the view

C There are multiple Publisher objects with the same name, so get() fails

D get_object should return a queryset, not a single object

💡 Hint

get() expects exactly one object. What if multiple objects match the filter?

get() raises MultipleObjectsReturned if more than one object matches the query. Here, multiple publishers share the same name.

🧠 Conceptual

expert

How to customize context data in a DetailView?

You want to add extra data to the template context in a DetailView. Which method should you override?

A get_context_data

B get_object

C dispatch

D render_to_response

💡 Hint

Think about where the context dictionary is prepared before rendering.

get_context_data allows you to add extra variables to the context passed to the template.

Practice

1. What is the primary purpose of Django's DetailView?

easy

A. To list multiple objects in a table format

B. To display details of a single object from the database

C. To create a new object via a form

D. To delete an object from the database

Solution

1. Step 1: Understand DetailView's role

   DetailView is designed to show details of one object, not multiple or form actions.

2. Step 2: Compare with other views

   ListView shows multiple objects, CreateView handles creation, DeleteView handles deletion.

3. Final Answer:

   To display details of a single object from the database -> Option B

4. Quick Check:

   DetailView = single object display [OK]

Hint: DetailView always shows one object's details [OK]

Common Mistakes:

• Confusing DetailView with ListView
• Thinking DetailView handles forms
• Assuming DetailView deletes objects

2. Which of the following is the correct way to specify the model in a Django DetailView?

easy

A. models = MyModel

B. Model = MyModel

C. model = MyModel

D. model_name = MyModel

Solution

1. Step 1: Check attribute naming conventions

   Django's DetailView expects the attribute model in lowercase to specify the model class.

2. Step 2: Validate other options

   Capitalized Model, plural models, or model_name are not recognized by DetailView.

3. Final Answer:

   model = MyModel -> Option C

4. Quick Check:

   Use lowercase 'model' attribute [OK]

Hint: Use lowercase 'model' to set the model in DetailView [OK]

Common Mistakes:

• Capitalizing 'Model' attribute
• Using plural 'models' instead of 'model'
• Trying 'model_name' instead of 'model'

3. Given this URL pattern:
path('product/<int:pk>/', ProductDetailView.as_view(), name='product-detail')
and this view:

class ProductDetailView(DetailView):
    model = Product
    template_name = 'product_detail.html'

What will ProductDetailView display when visiting /product/5/?

medium

A. Details of the Product object with primary key 5

B. A list of all Product objects

C. An error because template_name is missing

D. Details of the Product object with slug '5'

Solution

1. Step 1: Understand URL pattern and pk usage

   The URL uses <int:pk> which passes primary key 5 to the view.

2. Step 2: DetailView uses pk to fetch object

   DetailView fetches the Product object with pk=5 and renders 'product_detail.html'.

3. Final Answer:

   Details of the Product object with primary key 5 -> Option A

4. Quick Check:

   pk in URL = object detail shown [OK]

Hint: pk in URL selects object DetailView shows [OK]

Common Mistakes:

• Confusing pk with slug
• Expecting a list instead of single object
• Thinking template_name is required to avoid error

4. What is wrong with this DetailView code?

class ArticleDetailView(DetailView):
    model = Article
    template = 'article_detail.html'

medium

A. The attribute should be 'template_name', not 'template'

B. The model attribute must be a string, not a class

C. DetailView requires a get_queryset method

D. The class must inherit from ListView, not DetailView

Solution

1. Step 1: Check attribute for template file

   The correct attribute to specify the template is template_name, not template.

2. Step 2: Validate other options

   Model should be a class, get_queryset is optional, and DetailView is correct for single object display.

3. Final Answer:

   The attribute should be 'template_name', not 'template' -> Option A

4. Quick Check:

   Use 'template_name' to set template [OK]

Hint: Use 'template_name' attribute for templates [OK]

Common Mistakes:

• Using 'template' instead of 'template_name'
• Thinking model must be string
• Adding unnecessary get_queryset method

5. You want to create a DetailView for a BlogPost model that uses a slug in the URL instead of pk. Which is the correct way to configure the view and URL pattern?

hard

A. In the view, set model = BlogPost and slug_field = 'slug'; in URL use path('blog/<slug:slug>/', ...)

B. In the view, set model = BlogPost and slug_field = 'slug'; in URL use path('blog/<int:slug>/', ...)

C. In the view, set model = BlogPost and pk_url_kwarg = 'slug'; in URL use path('blog/<slug:slug>/', ...)

D. In the view, set model = BlogPost and slug_url_kwarg = 'slug'; in URL use path('blog/<slug:slug>/', ...)

Solution

1. Step 1: Understand slug configuration in DetailView

   DetailView uses pk by default. To use slug, set slug_url_kwarg = 'slug' if your URL kwarg is 'slug'. The slug_field defaults to 'slug' and usually does not need to be set unless your model field is named differently.

2. Step 2: Validate options

   In the view, set model = BlogPost and slug_url_kwarg = 'slug'; in URL use path('blog/<slug:slug>/', ...) correctly sets slug_url_kwarg to match the URL kwarg and uses the default slug_field. In the view, set model = BlogPost and slug_field = 'slug'; in URL use path('blog/<slug:slug>/', ...) incorrectly sets slug_field which is the model field name, not the URL kwarg. In the view, set model = BlogPost and pk_url_kwarg = 'slug'; in URL use path('blog/<slug:slug>/', ...) misuses pk_url_kwarg. In the view, set model = BlogPost and slug_field = 'slug'; in URL use path('blog/<int:slug>/', ...) uses wrong URL converter.

3. Final Answer:

   In the view, set model = BlogPost and slug_url_kwarg = 'slug'; in URL use path('blog/<slug:slug>/', ...) -> Option D

4. Quick Check:

   slug_url_kwarg matches URL kwarg [OK]

Hint: Set slug_url_kwarg='slug' to match URL kwarg [OK]

Common Mistakes:

• Confusing slug_field with slug_url_kwarg
• Using int converter for slug in URL
• Setting pk_url_kwarg instead of slug_url_kwarg