Model index reference

Index classes ease creating database indexes. They can be added using the Meta.indexes option. This document explains the API references of Index which includes the index options.

Referencing built-in indexes

Indexes are defined in django.db.models.indexes, but for convenience they’re imported into 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, db_tablespace=None)[source]

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

fields

Index.fields

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

By default, indexes are created with an ascending order for each column. To define an index with a descending order for a column, add a hyphen before the field’s name.

For example Index(fields=['headline', '-pub_date']) would create SQL with (headline, pub_date DESC). Index ordering isn’t supported on MySQL. In that case, a descending index is created as a normal index.

Changed in Django 2.1:

Older versions don’t accept a tuple.

name

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 (_).

db_tablespace

Index.db_tablespace
New in Django 2.0:

The name of the database tablespace to use for this index. For single field indexes, if db_tablespace isn’t provided, the index is created in the db_tablespace of the field.

If Field.db_tablespace isn’t specified (or if the index uses multiple fields), the index is created in tablespace specified in the db_tablespace option inside the model’s class Meta. If neither of those tablespaces are set, the index is created in the same tablespace as the table.

See also

For a list of PostgreSQL-specific indexes, see django.contrib.postgres.indexes.

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