mirror of
https://github.com/django/django.git
synced 2024-12-25 18:46:22 +00:00
49 lines
1.5 KiB
Plaintext
49 lines
1.5 KiB
Plaintext
======================================
|
|
PostgreSQL specific database functions
|
|
======================================
|
|
|
|
All of these functions are available from the
|
|
``django.contrib.postgres.functions`` module.
|
|
|
|
.. currentmodule:: django.contrib.postgres.functions
|
|
|
|
``RandomUUID``
|
|
==============
|
|
|
|
.. class:: RandomUUID()
|
|
|
|
Returns a version 4 UUID.
|
|
|
|
The `pgcrypto extension`_ must be installed. You can use the
|
|
:class:`~django.contrib.postgres.operations.CryptoExtension` migration
|
|
operation to install it.
|
|
|
|
.. _pgcrypto extension: https://www.postgresql.org/docs/current/static/pgcrypto.html
|
|
|
|
Usage example::
|
|
|
|
>>> from django.contrib.postgres.functions import RandomUUID
|
|
>>> Article.objects.update(uuid=RandomUUID())
|
|
|
|
``TransactionNow``
|
|
==================
|
|
|
|
.. class:: TransactionNow()
|
|
|
|
Returns the date and time on the database server that the current transaction
|
|
started. If you are not in a transaction it will return the date and time of
|
|
the current statement. This is a complement to
|
|
:class:`django.db.models.functions.Now`, which returns the date and time of the
|
|
current statement.
|
|
|
|
Note that only the outermost call to :func:`~django.db.transaction.atomic()`
|
|
sets up a transaction and thus sets the time that ``TransactionNow()`` will
|
|
return; nested calls create savepoints which do not affect the transaction
|
|
time.
|
|
|
|
Usage example::
|
|
|
|
>>> from django.contrib.postgres.functions import TransactionNow
|
|
>>> Article.objects.filter(published__lte=TransactionNow())
|
|
<QuerySet [<Article: How to Django>]>
|