diff options
Diffstat (limited to 'docs/ref/databases.txt')
| -rw-r--r-- | docs/ref/databases.txt | 15 |
1 files changed, 15 insertions, 0 deletions
diff --git a/docs/ref/databases.txt b/docs/ref/databases.txt index 3cff1c61cb..8b473da821 100644 --- a/docs/ref/databases.txt +++ b/docs/ref/databases.txt @@ -82,6 +82,21 @@ You should also audit your existing code for any instances of this behavior before enabling this feature. It's faster, but it provides less automatic protection for multi-call operations. +Indexes for ``varchar`` and ``text`` columns +~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ +.. versionadded:: 1.1.2 + +When specifying ``db_index=True`` on your model fields, Django typically +outputs a single ``CREATE INDEX`` statement. However, if the database type +for the field is either ``varchar`` or ``text`` (e.g., used by ``CharField``, +``FileField``, and ``TextField``), then Django will create +an additional index that uses an appropriate `PostgreSQL operator class`_ +for the column. The extra index is necessary to correctly perfrom +lookups that use the ``LIKE`` operator in their SQL, as is done with the +``contains`` and ``startswith`` lookup types. + +.. _PostgreSQL operator class: http://www.postgresql.org/docs/8.4/static/indexes-opclass.html + .. _mysql-notes: MySQL notes |