How do I run an update and select statements on the same queryset rather than having to do two queries: – one to select the object – and one to update the object The equivalent in SQL would be something like: update my_table set field_1 = ‘some value’ where pk_field = some_value 7 Answers 7
Is it possible to refresh the state of a django object from database? I mean behavior roughly equivalent to: new_self = self.__class__.objects.get(pk=self.pk) for each field of the record: setattr(self, field, getattr(new_self, field)) UPDATE: Found a reopen/wontfix war in the tracker: http://code.djangoproject.com/ticket/901. Still don’t understand why the maintainers don’t like this. 4 Answers 4
I have a model that represents paintings I present on my site. On the main webpage I’d like to show some of them: newest, one that was not visited for most time, most popular one and a random one. I’m using Django 1.0.2. While first 3 of them are easy to pull using django models, … Read more
There is a lot of documentation on how to serialize a Model QuerySet but how do you just serialize to JSON the fields of a Model Instance? 18 Answers 18
I’d like to update a table with Django – something like this in raw SQL: update tbl_name set name=”foo” where name=”bar” My first result is something like this – but that’s nasty, isn’t it? list = ModelClass.objects.filter(name=”bar”) for obj in list: obj.name=”foo” obj.save() Is there a more elegant way? 7 Answers 7
Django has various numeric fields available for use in models, e.g. DecimalField and PositiveIntegerField. Although the former can be restricted to the number of decimal places stored and the overall number of characters stored, is there any way to restrict it to storing only numbers within a certain range, e.g. 0.0-5.0 ? Failing that, is … Read more
I would like to change a name of specific fields in a model: class Foo(models.Model): name = models.CharField() rel = models.ForeignKey(Bar) should change to: class Foo(models.Model): full_name = models.CharField() odd_relation = models.ForeignKey(Bar) What’s the easiest way to do this using South? 6 Answers 6
I want to trigger a special action in the save() method of a Django model object when I’m saving a new record (not updating an existing record.) Is the check for (self.id != None) necessary and sufficient to guarantee the self record is new and not being updated? Any special cases this might overlook? 13 … Read more
What’s the best way to set a creation date for an object automatically, and also a field that will record when the object was last updated? models.py: created_at = models.DateTimeField(False, True, editable=False) updated_at = models.DateTimeField(True, True, editable=False) views.py: if request.method == ‘POST’: form = MyForm(request.POST) if form.is_valid(): obj = form.save(commit=False) obj.user = request.user obj.save() return … Read more
I’m defining my Django models right now and I realized that there wasn’t a OneToManyField in the model field types. I’m sure there’s a way to do this, so I’m not sure what I’m missing. I essentially have something like this: class Dude(models.Model): numbers = models.OneToManyField(‘PhoneNumber’) class PhoneNumber(models.Model): number = models.CharField() In this case, each … Read more
