diff options
Diffstat (limited to 'docs/ref')
| -rw-r--r-- | docs/ref/databases.txt | 29 |
1 files changed, 25 insertions, 4 deletions
diff --git a/docs/ref/databases.txt b/docs/ref/databases.txt index cbc75d6a9c..63cb5f279e 100644 --- a/docs/ref/databases.txt +++ b/docs/ref/databases.txt @@ -496,11 +496,32 @@ for the field. This affects :class:`~django.db.models.CharField`, :class:`~django.db.models.SlugField` and :class:`~django.db.models.CommaSeparatedIntegerField`. -DateTime fields -~~~~~~~~~~~~~~~ +.. _mysql-fractional-seconds: -MySQL does not store fractions of seconds. Fractions of seconds are truncated -to zero when the time is stored. +Fractional seconds support for Time and DateTime fields +~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ + +MySQL 5.6.4 and later can store fractional seconds, provided that the +column definition includes a fractional indication (e.g. ``DATETIME(6)``). +Earlier versions do not support them at all. + +Django will not upgrade existing columns to include fractional seconds if the +database server supports it. If you want to enable them on an existing database, +it's up to you to either manually update the column on the target database, by +executing a command like:: + + ALTER TABLE `your_table` MODIFY `your_datetime_column` DATETIME(6) + +or using a :class:`~django.db.migrations.operations.RunSQL` operation in a +:ref:`data migration <data-migrations>`. + +.. versionchanged:: 1.8 + + Previously, Django truncated fractional seconds from ``datetime`` and + ``time`` values when using the MySQL backend. Now it lets the database + decide whether it should drop that part of the value or not. By default, new + ``DateTimeField`` or ``TimeField`` columns are now created with fractional + seconds support on MySQL 5.6.4 or later. ``TIMESTAMP`` columns ~~~~~~~~~~~~~~~~~~~~~ |