/docs/ref/exceptions.txt

  1=================
  2Django Exceptions
  3=================
  4
  5
  6Django raises some Django specific exceptions as well as many standard
  7Python exceptions.
  8
  9Django-specific Exceptions
 10==========================
 11
 12.. module:: django.core.exceptions
 13    :synopsis: Django specific exceptions
 14
 15ObjectDoesNotExist and DoesNotExist
 16-----------------------------------
 17.. exception:: DoesNotExist
 18.. exception:: ObjectDoesNotExist
 19
 20    The :exc:`DoesNotExist` exception is raised when an object is not found
 21    for the given parameters of a query.
 22
 23    :exc:`ObjectDoesNotExist` is defined in :mod:`django.core.exceptions`.
 24    :exc:`DoesNotExist` is a subclass of the base :exc:`ObjectDoesNotExist`
 25    exception that is provided on every model class as a way of
 26    identifying the specific type of object that could not be found.
 27
 28    See :meth:`~django.db.models.query.QuerySet.get()` for further information
 29    on :exc:`ObjectDoesNotExist` and :exc:`DoesNotExist`.
 30
 31MultipleObjectsReturned
 32-----------------------
 33.. exception:: MultipleObjectsReturned
 34
 35    The :exc:`MultipleObjectsReturned` exception is raised by a query if only
 36    one object is expected, but multiple objects are returned. A base version
 37    of this exception is provided in :mod:`django.core.exceptions`; each model
 38    class contains a subclassed version that can be used to identify the
 39    specific object type that has returned multiple objects.
 40
 41    See :meth:`~django.db.models.query.QuerySet.get()` for further information.
 42
 43SuspiciousOperation
 44-------------------
 45.. exception:: SuspiciousOperation
 46
 47    The :exc:`SuspiciousOperation` exception is raised when a user has performed
 48    an operation that should be considered suspicious from a security perspective,
 49    such as tampering with a session cookie.
 50
 51PermissionDenied
 52----------------
 53.. exception:: PermissionDenied
 54
 55    The :exc:`PermissionDenied` exception is raised when a user does not have
 56    permission to perform the action requested.
 57
 58ViewDoesNotExist
 59----------------
 60.. exception:: ViewDoesNotExist
 61
 62    The :exc:`ViewDoesNotExist` exception is raised by
 63    :mod:`django.core.urlresolvers` when a requested view does not exist.
 64
 65MiddlewareNotUsed
 66-----------------
 67.. exception:: MiddlewareNotUsed
 68
 69    The :exc:`MiddlewareNotUsed` exception is raised when a middleware is not
 70    used in the server configuration.
 71
 72ImproperlyConfigured
 73--------------------
 74.. exception:: ImproperlyConfigured
 75
 76    The :exc:`ImproperlyConfigured` exception is raised when Django is
 77    somehow improperly configured -- for example, if a value in ``settings.py``
 78    is incorrect or unparseable.
 79
 80FieldError
 81----------
 82.. exception:: FieldError
 83
 84    The :exc:`FieldError` exception is raised when there is a problem with a
 85    model field. This can happen for several reasons:
 86
 87        - A field in a model clashes with a field of the same name from an
 88          abstract base class
 89        - An infinite loop is caused by ordering
 90        - A keyword cannot be parsed from the filter parameters
 91        - A field cannot be determined from a keyword in the query
 92          parameters
 93        - A join is not permitted on the specified field
 94        - A field name is invalid
 95        - A query contains invalid order_by arguments
 96
 97ValidationError
 98---------------
 99.. exception:: ValidationError
100
101    The :exc:`ValidationError` exception is raised when data fails form or
102    model field validation. For more information about validation, see
103    :doc:`Form and Field Validation </ref/forms/validation>`,
104    :ref:`Model Field Validation <validating-objects>` and the
105    :doc:`Validator Reference </ref/validators>`.
106
107.. currentmodule:: django.core.urlresolvers
108
109NoReverseMatch
110--------------
111.. exception:: NoReverseMatch
112
113    The :exc:`NoReverseMatch` exception is raised by
114    :mod:`django.core.urlresolvers` when a matching URL in your URLconf
115    cannot be identified based on the parameters supplied.
116
117.. currentmodule:: django.db
118
119Database Exceptions
120===================
121
122Django wraps the standard database exceptions :exc:`DatabaseError` and
123:exc:`IntegrityError` so that your Django code has a guaranteed common
124implementation of these classes. These database exceptions are
125provided in :mod:`django.db`.
126
127.. exception:: DatabaseError
128.. exception:: IntegrityError
129
130The Django wrappers for database exceptions behave exactly the same as
131the underlying database exceptions. See `PEP 249 - Python Database API
132Specification v2.0`_ for further information.
133
134.. _`PEP 249 - Python Database API Specification v2.0`: http://www.python.org/dev/peps/pep-0249/
135
136.. currentmodule:: django.db.transaction
137
138Transaction Exceptions
139======================
140
141.. exception:: TransactionManagementError
142
143    The :exc:`TransactionManagementError` is raised for any and all problems
144    related to database transactions. It is available from
145    :mod:`django.db.transaction`.
146
147Python Exceptions
148=================
149
150Django raises built-in Python exceptions when appropriate as well. See
151the Python `documentation`_ for further information on the built-in
152exceptions.
153
154.. _`documentation`: http://docs.python.org/lib/module-exceptions.html