=====================
Model index reference
=====================

.. module:: django.db.models.indexes

.. currentmodule:: django.db.models

.. versionadded:: 1.11

Index classes ease creating database indexes. This document explains the API
references of :class:`Index` which includes the `index options`_.

.. admonition:: Referencing built-in indexes

    Indexes are defined in ``django.db.models.indexes``, but for convenience
    they're imported into :mod:`django.db.models`. The standard convention is
    to use ``from django.db import models`` and refer to the indexes as
    ``models.<IndexClass>``.

``Index`` options
=================

.. class:: Index(fields=[], name=None)

    Creates an index (B-Tree) in the database.

``fields``
-----------

.. attribute:: Index.fields

A list of the name of the fields on which the index is desired.

``name``
--------

.. attribute:: Index.name

The name of the index. If ``name`` isn't provided Django will auto-generate a
name. For compatibility with different databases, index names cannot be longer
than 30 characters and shouldn't start with a number (0-9) or underscore (_).

.. seealso::

    Use the :class:`~django.db.migrations.operations.AddIndex` and
    :class:`~django.db.migrations.operations.RemoveIndex` operations to add
    and remove indexes.