=================

Django Exceptions

=================

Django raises some Django specific exceptions as well as many standard

Python exceptions.

Django-specific Exceptions

==========================

.. module:: django.core.exceptions

    :synopsis: Django specific exceptions

ObjectDoesNotExist and DoesNotExist

-----------------------------------

.. exception:: DoesNotExist

.. exception:: ObjectDoesNotExist

    The :exc:`DoesNotExist` exception is raised when an object is not found

    for the given parameters of a query.

    :exc:`ObjectDoesNotExist` is defined in :mod:`django.core.exceptions`.

    :exc:`DoesNotExist` is a subclass of the base :exc:`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 :meth:`~django.db.models.QuerySet.get()` for further information

    on :exc:`ObjectDoesNotExist` and :exc:`DoesNotExist`.

MultipleObjectsReturned

-----------------------

.. exception:: MultipleObjectsReturned

    The :exc:`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 :mod:`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 :meth:`~django.db.models.QuerySet.get()` for further information.

SuspiciousOperation

-------------------

.. exception:: SuspiciousOperation

    The :exc:`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.

PermissionDenied

----------------

.. exception:: PermissionDenied

    The :exc:`PermissionDenied` exception is raised when a user does not have

    permission to perform the action requested.

ViewDoesNotExist

----------------

.. exception:: ViewDoesNotExist

    The :exc:`ViewDoesNotExist` exception is raised by

    :mod:`django.core.urlresolvers` when a requested view does not exist.

MiddlewareNotUsed

-----------------

.. exception:: MiddlewareNotUsed

    The :exc:`MiddlewareNotUsed` exception is raised when a middleware is not

    used in the server configuration.

ImproperlyConfigured

--------------------

.. exception:: ImproperlyConfigured

    The :exc:`ImproperlyConfigured` exception is raised when Django is

    somehow improperly configured -- for example, if a value in ``settings.py``

    is incorrect or unparseable.

FieldError

----------

.. exception:: FieldError

    The :exc:`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

ValidationError

---------------

.. exception:: ValidationError

    The :exc:`ValidationError` exception is raised when data fails form or

    model field validation. For more information about validation, see

    :doc:`Form and Field Validation </ref/forms/validation>`,

    :ref:`Model Field Validation <validating-objects>` and the

    :doc:`Validator Reference </ref/validators>`.

Database Exceptions

===================

Django wraps the standard database exceptions :exc:`DatabaseError` and

:exc:`IntegrityError` so that your Django code has a guaranteed common

implementation of these classes. These database exceptions are

provided in :mod:`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.

.. _`PEP 249 - Python Database API Specification v2.0`: http://www.python.org/dev/peps/pep-0249/

Python Exceptions

=================

Django raises built-in Python exceptions when appropriate as well. See

the Python `documentation`_ for further information on the built-in

exceptions.

.. _`documentation`: http://docs.python.org/lib/module-exceptions.html