Django raises some of its own exceptions as well as standard Python exceptions.
\nDjango core exception classes are defined in django.core.exceptions.
AppRegistryNotReadyLink to this heading#This exception is raised when attempting to use models before the app\nloading process, which initializes the ORM, is\ncomplete.
\nObjectDoesNotExistLink to this heading#The base class for DoesNotExist exceptions;\na try/except for ObjectDoesNotExist will catch\nDoesNotExist exceptions for all models.
See get() for further information\non ObjectDoesNotExist and DoesNotExist.
EmptyResultSetLink to this heading#EmptyResultSet may be raised during query generation if a query won’t\nreturn any results. Most Django projects won’t encounter this exception,\nbut it might be useful for implementing custom lookups and expressions.
FieldDoesNotExistLink to this heading#The FieldDoesNotExist exception is raised by a model’s\n_meta.get_field() method when the requested field does not exist on the\nmodel or on the model’s parents.
MultipleObjectsReturnedLink to this heading#The MultipleObjectsReturned exception is raised by a query if only\none object is expected, but multiple objects are returned. A base version\nof this exception is provided in django.core.exceptions; each model\nclass contains a subclassed version that can be used to identify the\nspecific object type that has returned multiple objects.
See get() for further information.
SuspiciousOperationLink to this heading#The SuspiciousOperation exception is raised when a user has\nperformed an operation that should be considered suspicious from a security\nperspective, such as tampering with a session cookie. Subclasses of\nSuspiciousOperation include:
DisallowedHost
DisallowedModelAdminLookup
DisallowedModelAdminToField
DisallowedRedirect
InvalidSessionKey
RequestDataTooBig
SuspiciousFileOperation
SuspiciousMultipartForm
SuspiciousSession
TooManyFieldsSent
If a SuspiciousOperation exception reaches the WSGI handler level it is\nlogged at the Error level and results in\na HttpResponseBadRequest. See the logging\ndocumentation for more information.
PermissionDeniedLink to this heading#The PermissionDenied exception is raised when a user does not have\npermission to perform the action requested.
ViewDoesNotExistLink to this heading#The ViewDoesNotExist exception is raised by\ndjango.urls when a requested view does not exist.
MiddlewareNotUsedLink to this heading#The MiddlewareNotUsed exception is raised when a middleware is not\nused in the server configuration.
ImproperlyConfiguredLink to this heading#The ImproperlyConfigured exception is raised when Django is\nsomehow improperly configured – for example, if a value in settings.py\nis incorrect or unparseable.
FieldErrorLink to this heading#The FieldError exception is raised when there is a problem with a\nmodel field. This can happen for several reasons:
A field in a model clashes with a field of the same name from an\nabstract 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\nparameters
A join is not permitted on the specified field
A field name is invalid
A query contains invalid order_by arguments
ValidationErrorLink to this heading#The ValidationError exception is raised when data fails form or\nmodel field validation. For more information about validation, see\nForm and Field Validation,\nModel Field Validation and the\nValidator Reference.
NON_FIELD_ERRORSLink to this heading#ValidationErrors that don’t belong to a particular field in a form\nor model are classified as NON_FIELD_ERRORS. This constant is used\nas a key in dictionaries that otherwise map fields to their respective\nlist of errors.
URL Resolver exceptions are defined in django.urls.
Resolver404Link to this heading#The Resolver404 exception is raised by\nresolve() if the path passed to resolve() doesn’t\nmap to a view. It’s a subclass of django.http.Http404.
NoReverseMatchLink to this heading#The NoReverseMatch exception is raised by django.urls when a\nmatching URL in your URLconf cannot be identified based on the parameters\nsupplied.
Database exceptions may be imported from django.db.
Django wraps the standard database exceptions so that your Django code has a\nguaranteed common implementation of these classes.
\nThe Django wrappers for database exceptions behave exactly the same as\nthe underlying database exceptions. See PEP 249, the Python Database API\nSpecification v2.0, for further information.
\nAs per PEP 3134, a __cause__ attribute is set with the original\n(underlying) database exception, allowing access to any additional\ninformation provided.
Raised to prevent deletion of referenced objects when using\ndjango.db.models.PROTECT. models.ProtectedError is a subclass\nof IntegrityError.
Http exceptions may be imported from django.http.
UnreadablePostErrorLink to this heading#UnreadablePostError is raised when a user cancels an upload.
Transaction exceptions are defined in django.db.transaction.
TransactionManagementErrorLink to this heading#TransactionManagementError is raised for any and all problems\nrelated to database transactions.
Exceptions provided by the django.test package.
RedirectCycleErrorLink to this heading#RedirectCycleError is raised when the test client detects a\nloop or an overly long chain of redirects.
Django raises built-in Python exceptions when appropriate as well. See the\nPython documentation for further information on the Built-in Exceptions.
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