Django Exceptions¶

This exception is raised when attempting to use models before the app loading process, which initializes the ORM, is complete.

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 may be raised during query generation if a query won’t return any results. Most Django projects won’t encounter this exception, but it might be useful for implementing custom lookups and expressions.

The FieldDoesNotExist exception is raised by a model’s _meta.get_field() method when the requested field does not exist on the model or on the model’s parents.

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.

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.

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

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

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

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

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

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.

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.

The NoReverseMatch exception is raised by django.urls when a matching URL in your URLconf cannot be identified based on the parameters supplied.

UnreadablePostError is raised when a user cancels an upload.

TransactionManagementError is raised for any and all problems related to database transactions.

RedirectCycleError is raised when the test client detects a loop or an overly long chain of redirects.