User model overview in Django - Practice Problems & Coding Challenges

Challenge - 5 Problems

❓ component_behavior

intermediate

What is the default field used for user identification in Django's built-in User model?

Django's built-in User model uses a specific field as the unique identifier for users. Which field is it?

A username

B id

C email

D first_name

💡 Hint

Think about what users usually type to log in by default.

The default User model in Django uses the username field as the unique identifier for authentication.

❓ state_output

intermediate

What is the output of accessing the 'is_staff' attribute on a newly created Django User instance?

Consider this code:

from django.contrib.auth.models import User
user = User.objects.create_user('alice', '[e-mail]', 'password123')
print(user.is_staff)

What will be printed?

Django

from django.contrib.auth.models import User
user = User.objects.create_user('alice', '[e-mail]', 'password123')
print(user.is_staff)

A False

B True

C None

D Raises AttributeError

💡 Hint

By default, regular users are not staff members.

By default, is_staff is set to False for users created with create_user.

📝 Syntax

advanced

Which code snippet correctly creates a custom user model inheriting from AbstractBaseUser?

You want to create a custom user model in Django by inheriting from AbstractBaseUser. Which snippet is syntactically correct?

A

class CustomUser(AbstractBaseUser):
    email = models.EmailField(unique=True)
    USERNAME_FIELD = 'email'
    def __str__(self):
        return email

B

class CustomUser(AbstractBaseUser):
    email = models.EmailField(unique=True)
    USERNAME_FIELD = 'email'
    def __str__(self):
        return self.email()

C

class CustomUser(AbstractBaseUser):
    email = models.EmailField(unique=True)
    USERNAME_FIELD = email
    def __str__(self):
        return self.email

D

class CustomUser(AbstractBaseUser):
    email = models.EmailField(unique=True)
    USERNAME_FIELD = 'email'
    def __str__(self):
        return self.email

💡 Hint

Remember USERNAME_FIELD must be a string naming the field, and __str__ should return a string attribute.

Option D correctly sets USERNAME_FIELD as a string and returns self.email (an attribute) in __str__.

Option D misses quotes around 'email'.

Option D returns email which is undefined in the method scope.

Option D calls self.email() as a method, but it's a field.

🔧 Debug

advanced

What error occurs when trying to create a user without specifying USERNAME_FIELD in a custom user model?

Given a custom user model inheriting AbstractBaseUser but missing the USERNAME_FIELD attribute, what error will Django raise when creating a user?

A AttributeError: 'CustomUser' object has no attribute 'username'

B ValueError: The USERNAME_FIELD attribute must be set on the user model

C TypeError: create_user() missing 1 required positional argument

D OperationalError: no such column: username

💡 Hint

Django requires a field to identify users uniquely.

Django raises a ValueError if USERNAME_FIELD is not set in a custom user model.

🧠 Conceptual

expert

Which statement best describes the difference between AbstractUser and AbstractBaseUser in Django?

Choose the most accurate description of how AbstractUser and AbstractBaseUser differ in Django's user model system.

A AbstractUser is used only for admin users, AbstractBaseUser is for regular users.

B AbstractBaseUser includes all default fields and methods, while AbstractUser requires you to add username and password fields manually.

C AbstractUser provides a full User model with fields and methods, while AbstractBaseUser provides only core authentication features requiring full customization.

D AbstractUser and AbstractBaseUser are identical and interchangeable.

💡 Hint

Think about how much you need to build yourself with each base class.

AbstractUser is a full user model with username, email, and other fields already defined. You can extend it easily.

AbstractBaseUser provides only the core authentication features like password and last login, so you must define all other fields and methods yourself.

Practice

1. What is the primary purpose of Django's built-in User model?

easy

A. To manage static files like CSS and JavaScript

B. To handle database migrations automatically

C. To create HTML templates for user profiles

D. To store and manage user accounts including authentication

Solution

1. Step 1: Understand the role of the User model

   The User model in Django is designed to handle user accounts, including login and authentication.

2. Step 2: Compare options with User model functions

   Options B, C, and D relate to other Django features, not user management.

3. Final Answer:

   To store and manage user accounts including authentication -> Option D

4. Quick Check:

   User model = user account management [OK]

Hint: User model = user accounts and login management [OK]

Common Mistakes:

• Confusing User model with template or static file handling
• Thinking User model manages database migrations
• Assuming User model creates HTML pages

2. Which of the following is the correct way to import Django's default User model?

easy

A. from django.contrib.auth.models import User

B. import django.auth.User

C. from django.models import User

D. from django.contrib.auth import UserModel

Solution

1. Step 1: Recall the correct import path for User

   Django's default User model is located in django.contrib.auth.models.

2. Step 2: Check each option's syntax

   from django.contrib.auth.models import User matches the correct import syntax. Options A, C, and D are incorrect or invalid imports.

3. Final Answer:

   from django.contrib.auth.models import User -> Option A

4. Quick Check:

   Correct import path = from django.contrib.auth.models import User [OK]

Hint: User model is in django.contrib.auth.models [OK]

Common Mistakes:

• Using incorrect module paths
• Trying to import User directly from django.models
• Confusing User with UserModel

3. What will be the output of this code snippet?

from django.contrib.auth.models import User
user = User.objects.create_user(username='alice', password='pass123')
print(user.is_active)

medium

A. False

B. None

C. True

D. Raises an error

Solution

1. Step 1: Understand create_user default behavior

   The create_user method creates a user with is_active set to True by default.

2. Step 2: Check the printed attribute

   Printing user.is_active will output True unless explicitly changed.

3. Final Answer:

   True -> Option C

4. Quick Check:

   Default is_active = True [OK]

Hint: create_user sets is_active True by default [OK]

Common Mistakes:

• Assuming is_active is False by default
• Expecting None or error without context
• Confusing create_user with create_superuser

4. Identify the error in this code snippet that tries to create a user:

from django.contrib.auth.models import User
user = User.objects.create(username='bob', password='secret')

medium

A. Username must be an email address

B. Using create() instead of create_user() for password hashing

C. Password field cannot be set during user creation

D. Missing import for User model

Solution

1. Step 1: Check method used for user creation

   The create() method does not hash passwords; create_user() should be used instead.

2. Step 2: Analyze the impact of using create()

   Using create() stores the password as plain text, which is insecure and incorrect.

3. Final Answer:

   Using create() instead of create_user() for password hashing -> Option B

4. Quick Check:

   Use create_user() to hash passwords [OK]

Hint: Use create_user() to hash passwords, not create() [OK]

Common Mistakes:

• Using create() which stores raw passwords
• Forgetting to import User
• Thinking username must be email

5. You want to extend Django's default User model to add a 'birth_date' field. Which approach is recommended?

hard

A. Create a separate model with OneToOneField to User and add birth_date there

B. Directly add birth_date field to the built-in User model

C. Override User model by copying all fields and adding birth_date

D. Add birth_date as a global variable in settings.py

Solution

1. Step 1: Understand Django's recommended user extension

   Django suggests extending User by creating a profile model linked with OneToOneField.

2. Step 2: Evaluate options for adding fields

   Directly modifying built-in User or copying it is discouraged; settings.py cannot hold model fields.

3. Final Answer:

   Create a separate model with OneToOneField to User and add birth_date there -> Option A

4. Quick Check:

   Extend User via OneToOneField profile model [OK]

Hint: Extend User with OneToOneField profile model [OK]

Common Mistakes:

• Trying to modify built-in User model directly
• Copying User model instead of extending
• Adding model fields in settings.py