Added crossref targets for a couple of Django exceptions and cleaned up related reST markup.

table (usually called ``django_session``) and the

:class:`django.contrib.admin.models.LogEntry` table (usually called

``django_admin_log``). Those are the two standard tables that use

:class:`~django.db.model.TextField` internally.

:class:`~django.db.models.TextField` internally.

.. _fixed in MySQLdb 1.2.2: http://sourceforge.net/tracker/index.php?func=detail&aid=1495765&group_id=22307&atid=374932

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

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

.. currentmodule:: django.core.urlresolvers

NoReverseMatch

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

.. exception:: NoReverseMatch

    The :exc:`NoReverseMatch` exception is raised by

    :mod:`django.core.urlresolvers` when a matching URL in your URLconf

    cannot be identified based on the parameters supplied.

.. currentmodule:: django.db

Database Exceptions

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

implementation of these classes. These database exceptions are

provided in :mod:`django.db`.

.. exception:: DatabaseError

.. exception:: IntegrityError

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.

Load a custom template tag set.

For example, the following template would load all the tags and filters registered

in ``somelibrary`` and ``otherlibrary``::

For example, the following template would load all the tags and filters

registered in ``somelibrary`` and ``otherlibrary``::

    {% load somelibrary otherlibrary %}

    {% load foo bar from somelibrary %}

See :doc:`Custom tag and filter libraries </howto/custom-template-tags>` for more information.

See :doc:`Custom tag and filter libraries </howto/custom-template-tags>` for

more information.

.. templatetag:: now

path to the view.

Note that if the URL you're reversing doesn't exist, you'll get an

:exc:`NoReverseMatch` exception raised, which will cause your site to display an

error page.

:exc:`~django.core.urlresolvers.NoReverseMatch` exception raised, which will

cause your site to display an error page.

If you'd like to retrieve a URL without displaying it, you can use a slightly

different call::

Models and databases

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

.. module:: django.db

A model is the single, definitive source of data about your data. It contains

the essential fields and behaviors of the data you're storing. Generally, each

model maps to a single database table.