Django raises some Django specific exceptions as well as many standard Python exceptions.
The DoesNotExist exception is raised when an object is not found for the given parameters of a query.
ObjectDoesNotExist is defined in django.core.exceptions. DoesNotExist is a subclass of the base ObjectDoesNotExist exception that is provided on every model class as a way of identifying the specific type of object that could not be found.
See get() for further information on ObjectDoesNotExist and DoesNotExist.
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 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
Django wraps the standard database exceptions DatabaseError and IntegrityError so that your Django code has a guaranteed common implementation of these classes. These database exceptions are provided in django.db.
The Django wrappers for database exceptions behave exactly the same as the underlying database exceptions. See PEP 249 - Python Database API Specification v2.0 for further information.
Django raises built-in Python exceptions when appropriate as well. See the Python documentation for further information on the built-in exceptions.
Jun 28, 2011