Django raises some of its own exceptions as well as standard Python exceptions.
Django core exception classes are defined in django.core.exceptions
.
AppRegistryNotReady
¶This exception is raised when attempting to use models before the app loading process, which initializes the ORM, is complete.
ObjectDoesNotExist
¶The base class for DoesNotExist
exceptions;
a try/except
for ObjectDoesNotExist
will catch
DoesNotExist
exceptions for all models.
See get()
for further information
on ObjectDoesNotExist
and DoesNotExist
.
EmptyResultSet
¶FieldDoesNotExist
¶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. Subclasses of
SuspiciousOperation
include:
DisallowedHost
DisallowedModelAdminLookup
DisallowedModelAdminToField
DisallowedRedirect
InvalidSessionKey
RequestDataTooBig
SuspiciousFileOperation
SuspiciousMultipartForm
SuspiciousSession
TooManyFieldsSent
If a SuspiciousOperation
exception reaches the WSGI handler level it is
logged at the Error
level and results in
a HttpResponseBadRequest
. See the logging
documentation for more information.
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.urls
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
A field cannot be determined from a keyword in the query parameters
A join is not permitted on the specified field
A field name is invalid
A query contains invalid order_by arguments
ValidationError
¶The ValidationError
exception is raised when data fails form or
model field validation. For more information about validation, see
Form and Field Validation,
Model Field Validation and the
Validator Reference.
NON_FIELD_ERRORS
¶ValidationError
s that don’t belong to a particular field in a form
or model are classified as NON_FIELD_ERRORS
. This constant is used
as a key in dictionaries that otherwise map fields to their respective
list of errors.
URL Resolver exceptions are defined in django.urls
.
Resolver404
¶The Resolver404
exception is raised by
resolve()
if the path passed to resolve()
doesn’t
map to a view. It’s a subclass of django.http.Http404
.
NoReverseMatch
¶The NoReverseMatch
exception is raised by django.urls
when a
matching URL in your URLconf cannot be identified based on the parameters
supplied.
Database exceptions may be imported from django.db
.
Django wraps the standard database exceptions so that your Django code has a guaranteed common implementation of these classes.
The Django wrappers for database exceptions behave exactly the same as the underlying database exceptions. See PEP 249, the Python Database API Specification v2.0, for further information.
As per PEP 3134, a __cause__
attribute is set with the original
(underlying) database exception, allowing access to any additional
information provided.
Raised to prevent deletion of referenced objects when using
django.db.models.PROTECT
. models.ProtectedError
is a subclass
of IntegrityError
.
Http exceptions may be imported from django.http
.
UnreadablePostError
¶UnreadablePostError
is raised when a user cancels an upload.
Transaction exceptions are defined in django.db.transaction
.
TransactionManagementError
¶TransactionManagementError
is raised for any and all problems
related to database transactions.
Exceptions provided by the django.test
package.
RedirectCycleError
¶RedirectCycleError
is raised when the test client detects a
loop or an overly long chain of redirects.
Django raises built-in Python exceptions when appropriate as well. See the Python documentation for further information on the Built-in Exceptions.
Dec 25, 2023