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Django compatibility
====================
This package has been tested with:
* Django versions 2.2 up to 4.0
* Python versions 3.6 and up
See the `the tox.ini file <https://github.com/django-parler/django-parler/blob/master/tox.ini>`_
for the compatibility testing matrix.
.. _orm-restrictions:
Using multiple ``filter()`` calls
---------------------------------
Since translated fields live in a separate model,
they can be filtered like any normal relation::
object = MyObject.objects.filter(translations__title='cheese omelet')
translation1 = myobject.translations.all()[0]
However, if you have to query a language or translated attribute, this should happen in a single query.
That can either be a single
:func:`~django.db.models.query.QuerySet.filter`,
:func:`~parler.managers.TranslatableManager.translated` or
:func:`~parler.managers.TranslatableManager.active_translations`) call::
from parler.utils import get_active_language_choices
MyObject.objects.filter(
translations__language_code__in=get_active_language_choices(),
translations__slug='omelette'
)
Queries on translated fields, even just ``.translated()`` spans a relationship.
Hence, they can't be combined with other filters on translated fields,
as that causes double joins on the translations table.
See `the ORM documentation <https://docs.djangoproject.com/en/dev/topics/db/queries/#spanning-multi-valued-relationships>`_ for more details.
.. _ordering:
The ``ordering`` meta field
---------------------------
It's not possible to order on translated fields by default.
Django won't allow the following::
from django.db import models
from parler.models import TranslatableModel, TranslatedFields
class MyModel(TranslatableModel):
translations = TranslatedFields(
title = models.CharField(max_length=100),
)
class Meta:
ordering = ('title',) # NOT ALLOWED
def __unicode__(self):
return self.title
You can however, perform ordering within the queryset::
MyModel.objects.translated('en').order_by('translations__title')
You can also use the provided classes to perform the sorting within Python code.
* For the admin :attr:`~django.contrib.admin.ModelAdmin.list_filter` use: :class:`~parler.admin.SortedRelatedFieldListFilter`
* For forms widgets use: :class:`~parler.widgets.SortedSelect`, :class:`~parler.widgets.SortedSelectMultiple`, :class:`~parler.widgets.SortedCheckboxSelectMultiple`
.. _admin-compat:
Using ``search_fields`` in the admin
------------------------------------
When translated fields are included in the :attr:`~django.contrib.admin.ModelAdmin.search_fields`,
they should be includes with their full ORM path. For example::
from parler.admin import TranslatableAdmin
class MyModelAdmin(TranslatableAdmin):
search_fields = ('translations__title',)
Using ``prepopulated_fields`` in the admin
------------------------------------------
Using :attr:`~django.contrib.admin.ModelAdmin.prepopulated_fields` doesn't work yet,
as the admin will complain that the field does not exist.
Use :func:`~django.contrib.admin.ModelAdmin.get_prepopulated_fields` as workaround::
from parler.admin import TranslatableAdmin
class MyModelAdmin(TranslatableAdmin):
def get_prepopulated_fields(self, request, obj=None):
# can't use `prepopulated_fields = ..` because it breaks the admin validation
# for translated fields. This is the official django-parler workaround.
return {
'slug': ('title',)
}
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