# Django 4.1.8.dev20230308103347 ドキュメント

# Tablespaces

A common paradigm for optimizing performance in database systems is the use of tablespaces to organize disk layout.

警告

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 `db_tablespace` option inside the model's `class Meta`. This option also affects tables automatically created for `ManyToManyField`s in the model.

You can use the `DEFAULT_TABLESPACE` setting to specify a default value for `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 `db_tablespace` option to an `Index` constructor to specify the name of a tablespace to use for the index. For single field indexes, you can pass the `db_tablespace` option to a `Field` constructor to specify an alternate tablespace for the field's column index. If the column doesn't have an index, the option is ignored.

You can use the `DEFAULT_INDEX_TABLESPACE` setting to specify a default value for `db_tablespace`.

If `db_tablespace` isn't specified and you didn't set `DEFAULT_INDEX_TABLESPACE`, the index is created in the same tablespace as the tables.

## An example

    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)
        shortcut = models.CharField(max_length=7)
        edges = models.ManyToManyField(to="self", db_tablespace="indexes")

        class Meta:
            db_tablespace = "tables"
            indexes = [models.Index(fields=['shortcut'], db_tablespace='other_indexes')]

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. The index for the `shortcut` field would be stored in the `other_indexes` tablespace.

## Database support

PostgreSQL and Oracle support tablespaces. SQLite, MariaDB and MySQL don't.

When you use a backend that lacks support for tablespaces, Django ignores all tablespace-related options.