An exception is an abnormal event that results in to program failure. To handle this situation, Django uses its own exception classes and it supports all the core Python exceptions as well. These core exceptions classes are defined in the django.core.exceptions module.
|AppRegistryNotReady||This exception is raised when we attempt to use models before the app loading process.|
|ObjectDoesNotExist||This is the base class for DoesNotExist exceptions.|
|EmptyResultSet||This exception is rased if a query does not return any result.|
|FieldDoesNotExist||This exception is raised when the requested field does not exist.|
|MultipleObjectsReturned||This exception is raised if only one object is expected, but multiple objects are returned.|
|SuspiciousOperation||This exception is raised if a user has performed an operation that is considered suspicious from a security perspective.|
|PermissionDenied||This exception is raised when a user does not have permission to perform the action requested.|
|ViewDoesNotExist||This exception is raised by django.urls when a requested view does not exist.|
|MiddlewareNotUsed||This exception is raised when a middleware is not used in the server configuration.|
|ImproperlyConfigured||This exception is raised when Django is somehow improperly configured.|
|FieldError||This exception is raised when there is a problem with a model field.|
|ValidationError||This exception is raised when data validation fails form or model field validation.|
These exceptions are defined in the django.urls module.
|Resolver404||This exception is raised when the path passed to resolve() function does not map to a view.|
|NoReverseMatch||This exception is raised when a matching URL in your URLconf cannot be identified based on the parameters supplied.|
These exceptions are defined in the django.db module.
|DatabaseError||This exception occurs when the database is not available.|
|IntegrityError||This exception occurs when an insertion query executes.|
|DataError||This exception occurs when data related issues come into the database.|
The following exceptions are defined in django.http module.
|UnreadablePostError||This exception is raised when a user cancels an upload.|
These transaction exceptions are defined in the django.db.transaction.
|TransactionManagementError||This exception is raised for any and all problems related to the database transactions.|
Suppose, we want to get the employee record where id = 12, our view function will look like below. It raises a DoesNotExist exception if the data is not found. This is Django's built-in exception.// views.py
def getdata(request): data = Employee.objects.get(id=12) return HttpResponse(data)
It will show the following exception because no record is available in the database at id 12.
We can handle this exception by using try and except.// Views.py
def getdata(request): try: data = Employee.objects.get(id=12) except ObjectDoesNotExist: return HttpResponse("Exception: Data not found") return HttpResponse(data);