This exception is raised when attempting to use models before theapploading process, which initializes the ORM, iscomplete.

The base class forDoesNotExist exceptions;atry/except forObjectDoesNotExist will catchDoesNotExist exceptions for all models.

Seeget() for further informationonObjectDoesNotExist andDoesNotExist.

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

TheFieldDoesNotExist exception is raised by a model’s_meta.get_field() method when the requested field does not exist on themodel or on the model’s parents.

TheMultipleObjectsReturned exception is raised by a query if onlyone object is expected, but multiple objects are returned. A base versionof this exception is provided indjango.core.exceptions; each modelclass contains a subclassed version that can be used to identify thespecific object type that has returned multiple objects.

Seeget() for further information.

TheSuspiciousOperation exception is raised when a user hasperformed an operation that should be considered suspicious from a securityperspective, such as tampering with a session cookie. Subclasses ofSuspiciousOperation include:

• DisallowedHost
• DisallowedModelAdminLookup
• DisallowedModelAdminToField
• DisallowedRedirect
• InvalidSessionKey
• RequestDataTooBig
• SuspiciousFileOperation
• SuspiciousMultipartForm
• SuspiciousSession
• TooManyFieldsSent

If aSuspiciousOperation exception reaches the WSGI handler level it islogged at theError level and results inaHttpResponseBadRequest. See theloggingdocumentation for more information.

ThePermissionDenied exception is raised when a user does not havepermission to perform the action requested.

TheViewDoesNotExist exception is raised bydjango.urls when a requested view does not exist.

TheMiddlewareNotUsed exception is raised when a middleware is notused in the server configuration.

TheImproperlyConfigured exception is raised when Django issomehow improperly configured – for example, if a value insettings.pyis incorrect or unparseable.

TheFieldError exception is raised when there is a problem with amodel field. This can happen for several reasons:

• A field in a model clashes with a field of the same name from anabstract 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 queryparameters
• A join is not permitted on the specified field
• A field name is invalid
• A query contains invalid order_by arguments

TheValidationError exception is raised when data fails form ormodel field validation. For more information about validation, seeForm and Field Validation,Model Field Validation and theValidator Reference.

TheResolver404 exception is raised byresolve() if the path passed toresolve() doesn’tmap to a view. It’s a subclass ofdjango.http.Http404.

TheNoReverseMatch exception is raised bydjango.urls when amatching URL in your URLconf cannot be identified based on the parameterssupplied.

UnreadablePostError is raised when a user cancels an upload.

TransactionManagementError is raised for any and all problemsrelated to database transactions.

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