Question Details

No question body available.

Tags

python django django-models

Answers (3)

Accepted Answer Available
Accepted Answer
October 5, 2025 Score: 0 Rep: 482,098 Quality: High Completeness: 80%

This makes me wary of using the attribute in queries.

You are not really using attributes in a query. You are only using attributes from the class that are subclasses of django.db.models.fields.Field. So you can not filter with an arbitrary attribute, or method.

Luckily, if we look at the source code of .getusername(…) [GitHub], it says:

def getusername(self):
    """Return the username for this User."""
    return getattr(self, self.USERNAMEFIELD)

this is used for example if you want to use the email field instead of username, or when make a custom user model with another field.

We can then make the query with:

from django.contrib.auth.models import User
bob = User.objects.get({User.USERNAME_FIELD: 'Bob'})
October 4, 2025 Score: 0 Rep: 5,526 Quality: Low Completeness: 60%

If you want to retrieve a user instance from the database, the preferred way is to either use the get or getobjector404 method:

User.objects.get(username="Bob")

The two methods serve different purposes: The getusername() method returns the username for the currently logged-in user. You should not use this to retrieve the records of a random user. Also note that this method returns the record used as USERNAMEFIELD which can be a username, an email or any other unique identifier because Django User model can be swapped out.

The get() method on the other hand retrieves the model instance that is being requested. You can use this if you want to get a user instance using the username. Ensure to handle the DoesNotExist Exception if the object doesn't exist and the MultipleObjectsReturned if your username field is not unique:

try:
    User.objects.get(username="Bob")
except User.DoesNotExist:
    ...
except MultipleObjectsReturned:
    ...

Or you can also use the getobjector404 method.

October 5, 2025 Score: 0 Rep: 1 Quality: Low Completeness: 50%

You can’t use getusername() in a queryset - it’s just a Python method, not a database field.
For lookups, you must query by the actual field name:

bob = User.objects.get(username="Bob")

If you really want a method-based approach, you can define your own model method or manager method, for example:

class CustomUserManager(models.Manager):
    def getbyusername(self, username):
        return self.get(username=username)
class User(AbstractUser):
    objects = CustomUserManager()

then you can use like this:


bob = User.objects.getby_username("Bob")