I created a ticket <https://code.djangoproject.com/ticket/31231> about the
similliar problem, but after answer I don't sure that it's bug.
Nevertheless, I think It looks contradictory, because you use python None
in case of creating, but {{{ __isnull=True }}} in case of filtering.
In case, that I described bellow, it also looks strange.
TestModel.objects.create(json_field=None) creates SQL NULL, but
TestModel.objects.create(json_field={'key': None}) creates JSON NULL.
May be this behaviour needs to change? Or is it better to extend the
documentation?
Is this API allow to create a field with just JSON NULL value?
class TestJsonbNull(TestCase):
def setUp(self):
TestModel.objects.create(json_field=None)
TestModel.objects.create(json_field={'key': None})
# test passed
def test_1(self):
self.assertTrue(TestModel.objects.filter(json_field=None).exists())
# test failed
def test_2(self):
self.assertTrue(TestModel.objects.filter(json_field__key=None).
exists())
вторник, 12 июля 2016 г., 18:56:47 UTC+5 пользователь [email protected]
написал:
>
> I believe I found a limitation in the Django jsonb support, but I'm really
> not sure how the framework could fix it beside adding a limitation section
> in the documentation.
>
> Basically, it is possible to fetch models with json 'null' values but it
> is not possible to save them back (Django converts the json 'null' value to
> sql NULL value).
>
> Assume the following model:
>
> class Container(models.Model):
> data = JSONField(blank=False, null=False) # emphasis on null=False
>
>
> In PostgreSQL, it is perfectly reasonable to do this:
>
> INSERT INTO container VALUES (1, 'null');
>
>
> If you fetch the row in Django, you will get this:
>
> container = Container.objects.get(pk=1)
>
> assert container.data is None # passes
>
> container.save() # raises IntegrityError because it tries to save NULL in
> a NOT NULL column.
>
>
> This is because Django has no idea whether you want to store None or
> 'null'::jsonb.
>
>
> I'm not sure if this limitation was discussed elsewhere. I found a
> somehow-related ticket here: https://code.djangoproject.com/ticket/25718.
>
>
> Barthélémy
>
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