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django/docs/topics/db/tablespaces.txt
Dominic Rodger c33d1ca1d9 Fixed #20852 - Fixed incorrectly generated left quotes in docs.
Sphinx generates left single quotes for apostrophes after
code markup, when right single quotes are required. The
easiest way to fix this is just by inserting the unicode
character for a right single quote.

Instances of the problem were found by looking for
">‘" in the generated HTML.
2013-08-06 07:13:17 -04:00

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===========
Tablespaces
===========
A common paradigm for optimizing performance in database systems is the use of
`tablespaces`_ to organize disk layout.
.. _`tablespaces`: http://en.wikipedia.org/wiki/Tablespace
.. warning::
Django does not create the tablespaces for you. Please refer to your
database engine's documentation for details on creating and managing
tablespaces.
Declaring tablespaces for tables
--------------------------------
A tablespace can be specified for the table generated by a model by supplying
the :attr:`~django.db.models.Options.db_tablespace` option inside the model's
``class Meta``. This option also affects tables automatically created for
:class:`~django.db.models.ManyToManyField`\ s in the model.
You can use the :setting:`DEFAULT_TABLESPACE` setting to specify a default value
for :attr:`~django.db.models.Options.db_tablespace`. This is useful for setting
a tablespace for the built-in Django apps and other applications whose code you
cannot control.
Declaring tablespaces for indexes
---------------------------------
You can pass the :attr:`~django.db.models.Field.db_tablespace` option to a
``Field`` constructor to specify an alternate tablespace for the ``Field``s
column index. If no index would be created for the column, the option is
ignored.
You can use the :setting:`DEFAULT_INDEX_TABLESPACE` setting to specify
a default value for :attr:`~django.db.models.Field.db_tablespace`.
If :attr:`~django.db.models.Field.db_tablespace` isn't specified and you didn't
set :setting:`DEFAULT_INDEX_TABLESPACE`, the index is created in the same
tablespace as the tables.
An example
----------
.. code-block:: python
class TablespaceExample(models.Model):
name = models.CharField(max_length=30, db_index=True, db_tablespace="indexes")
data = models.CharField(max_length=255, db_index=True)
edges = models.ManyToManyField(to="self", db_tablespace="indexes")
class Meta:
db_tablespace = "tables"
In this example, the tables generated by the ``TablespaceExample`` model (i.e.
the model table and the many-to-many table) would be stored in the ``tables``
tablespace. The index for the name field and the indexes on the many-to-many
table would be stored in the ``indexes`` tablespace. The ``data`` field would
also generate an index, but no tablespace for it is specified, so it would be
stored in the model tablespace ``tables`` by default.
Database support
----------------
PostgreSQL and Oracle support tablespaces. SQLite and MySQL don't.
When you use a backend that lacks support for tablespaces, Django ignores all
tablespace-related options.