Custom user model with AbstractUser in Django - Step-by-Step Execution

Concept Flow - Custom user model with AbstractUser

Define CustomUser class

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Inherit AbstractUser

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Add custom fields/methods

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Update settings.py: AUTH_USER_MODEL

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Run migrations

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Use CustomUser in app

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Authentication and user management with new model

This flow shows how to create a custom user model by extending AbstractUser, update settings, migrate, and then use the new user model.

Execution Sample

Django

from django.contrib.auth.models import AbstractUser
from django.db import models

class CustomUser(AbstractUser):
    age = models.PositiveIntegerField(null=True, blank=True)

# settings.py
AUTH_USER_MODEL = 'myapp.CustomUser'

Defines a CustomUser model extending AbstractUser with an extra 'age' field and sets it as the user model in settings.

Execution Table

Step	Action	Code/Setting	Result/Effect
1	Define CustomUser class	class CustomUser(AbstractUser): age = models.PositiveIntegerField(null=True, blank=True)	CustomUser model created with all AbstractUser fields plus 'age'
2	Update settings.py	AUTH_USER_MODEL = 'myapp.CustomUser'	Django uses CustomUser as the user model
3	Run makemigrations	python manage.py makemigrations	Migration file created for CustomUser model
4	Run migrate	python manage.py migrate	Database tables updated to include CustomUser
5	Use CustomUser in app	from django.contrib.auth import get_user_model	CustomUser is used for authentication and user management
6	Exit	N/A	Setup complete, app uses CustomUser

💡 Setup stops after migrations and app uses CustomUser for authentication

Variable Tracker

Variable	Start	After Step 1	After Step 2	After Step 3	After Step 4	Final
CustomUser	Not defined	Defined with AbstractUser + age	Same	Same	Same	Same
AUTH_USER_MODEL	Default 'auth.User'	Default	'myapp.CustomUser'	'myapp.CustomUser'	'myapp.CustomUser'	'myapp.CustomUser'
Migration files	None	None	None	New migration created	Applied to DB	Applied to DB

Key Moments - 3 Insights

Why must AUTH_USER_MODEL be set before the first migrate?

Because Django creates the user table on first migrate; changing AUTH_USER_MODEL later causes conflicts. See execution_table steps 2-4.

Can I add fields directly to AbstractUser?

No, you create a subclass (CustomUser) to add fields. AbstractUser is a base class. See step 1 in execution_table.

How do I reference the custom user model in code?

Use get_user_model() to get the current user model, ensuring compatibility. See step 5 in execution_table.

Visual Quiz - 3 Questions

Look at the execution table, what happens at step 3?

A Run migrate to apply database changes

B Define the CustomUser class

C Create migration files for CustomUser

D Update settings.py to set AUTH_USER_MODEL

💡 Hint

Check the 'Action' and 'Code/Setting' columns at step 3 in execution_table

At which step does Django start using the CustomUser model for authentication?

A Step 2

B Step 5

C Step 4

D Step 1

💡 Hint

Look for when the app imports and uses the user model in execution_table

If you forget to set AUTH_USER_MODEL before migrating, what is the likely result?

A Django uses the default User model and migrations conflict later

B CustomUser is used anyway without issues

C Migrations run faster

D Django raises an error immediately

💡 Hint

Refer to key_moments about setting AUTH_USER_MODEL before first migrate

Concept Snapshot

Custom user model with AbstractUser:
- Create a class inheriting AbstractUser
- Add custom fields as needed
- Set AUTH_USER_MODEL in settings.py
- Run makemigrations and migrate
- Use get_user_model() to access the user model
- Must set AUTH_USER_MODEL before first migrate

Full Transcript

To create a custom user model in Django, define a class that inherits from AbstractUser and add any extra fields you want. Then, update your settings.py file to set AUTH_USER_MODEL to point to your new model. After that, run makemigrations and migrate to create the necessary database tables. Finally, use get_user_model() in your code to reference the custom user model. Remember, you must set AUTH_USER_MODEL before running your first migrate to avoid conflicts.