Created special PostgreSQL text indexes when unique is True

Refs #19441.

1 files changed, 3 insertions, 0 deletions

diff --git a/docs/ref/models/fields.txt b/docs/ref/models/fields.txt
index 6498b6c845..77b838622b 100644
--- a/docs/ref/models/fields.txt
+++ b/docs/ref/models/fields.txt
@@ -272,6 +272,9 @@ field, a :exc:`django.db.IntegrityError` will be raised by the model's
 This option is valid on all field types except :class:`ManyToManyField` and
 :class:`FileField`.
 
+Note that when ``unique`` is ``True``, you don't need to specify
+:attr:`~Field.db_index`, because ``unique`` implies the creation of an index.
+
 ``unique_for_date``
 -------------------