Django Exceptions

Django raises some Django specific exceptions as well as many standard Python exceptions.

Django-specific Exceptions

ObjectDoesNotExist and DoesNotExist

The DoesNotExist exception is raised when an object is not found for the given parameters of a query.

ObjectDoesNotExist is defined in django.core.exceptions. DoesNotExist is a subclass of the base ObjectDoesNotExist exception that is provided on every model class as a way of identifying the specific type of object that could not be found.

See get() for further information on ObjectDoesNotExist and DoesNotExist.

MultipleObjectsReturned

The MultipleObjectsReturned exception is raised by a query if only one object is expected, but multiple objects are returned. A base version of this exception is provided in django.core.exceptions; each model class contains a subclassed version that can be used to identify the specific object type that has returned multiple objects.

See get() for further information.

SuspiciousOperation

The SuspiciousOperation exception is raised when a user has performed an operation that should be considered suspicious from a security perspective, such as tampering with a session cookie.

PermissionDenied

The PermissionDenied exception is raised when a user does not have permission to perform the action requested.

ViewDoesNotExist

The ViewDoesNotExist exception is raised by django.core.urlresolvers when a requested view does not exist.

MiddlewareNotUsed

The MiddlewareNotUsed exception is raised when a middleware is not used in the server configuration.

ImproperlyConfigured

The ImproperlyConfigured exception is raised when Django is somehow improperly configured – for example, if a value in settings.py is incorrect or unparseable.

FieldError

The FieldError exception is raised when there is a problem with a model field. This can happen for several reasons:

  • A field in a model clashes with a field of the same name from an abstract base class
  • An infinite loop is caused by ordering
  • A keyword cannot be parsed from the filter parameters
  • If a field cannot be determined from a keyword in the query parameters
  • If a join is not permitted on the specified field
  • If a field name is invalid
  • If a query contains invalid order_by arguments

Database Exceptions

Django wraps the standard database exceptions DatabaseError and IntegrityError so that your Django code has a guaranteed common implementation of these classes. These database exceptions are provided in django.db.

The Django wrappers for database exceptions behave exactly the same as the underlying database exceptions. See PEP 249 - Python Database API Specification v2.0 for further information.

Python Exceptions

Django raises built-in Python exceptions when appropriate as well. See the Python documentation for further information on the built-in exceptions.

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