this line of code at = AttachedInfo.objects.filter(attachedMarker=m.id, title=title) returns a queryset and you are trying to access a field of it (that does not exist). what you probably need is at = AttachedInfo.objects.get(attachedMarker=m.id, title=title)
Yes, I think you want make = Make.objects.get(pk=1) make.make_content_set.filter(published=True) or maybe make_ids = MakeContent.objects.filter(published=True).values_list(‘make_id’, flat=True) makes = Make.objects.filter(id__in=make_ids)
If title and body are fields in your model, then you can deliver the keyword arguments in your dictionary using the ** operator. Assuming your model is called MyModel: # create instance of model m = MyModel(**data_dict) # don’t forget to save to database! m.save() As for your second question, the dictionary has to be … Read more
from django.db.models import Q User.objects.filter(Q(income__gte=5000) | Q(income__isnull=True)) via Documentation
In your admin definition, you can define a queryset() method that returns the queryset for that model’s admin. eg: class MyModelAdmin(admin.ModelAdmin): def queryset(self, request): qs = super(MyModelAdmin, self).queryset(request) return qs.filter(user=request.user) Then only objects with user=request.user will be visible in the admin.
This is exactly what select_related() does. The only gotcha is that you have to start with the Answer model, rather than Question, but the result is the same: answers = Answer.objects.filter(question_id=1).select_related() Now each answer object has a pre-fetched ‘question’ attribute, and accessing it won’t hit the db again.
F objects. from django.db.models import F stale_activities = Activity.objects.filter(updated__gte=F(‘added_toSolr_date’))
Although the Django docs recommend using count rather than len: Note: Don’t use len() on QuerySets if all you want to do is determine the number of records in the set. It’s much more efficient to handle a count at the database level, using SQL’s SELECT COUNT(*), and Django provides a count() method for precisely … Read more
I would focus on the example queries rather than your quote from the documentation. Aggregate calculates values for the entire queryset. Annotate calculates summary values for each item in the queryset. Aggregation >>> Book.objects.aggregate(average_price=Avg(‘price’)) {‘average_price’: 34.35} Returns a dictionary containing the average price of all books in the queryset. Annotation >>> q = Book.objects.annotate(num_authors=Count(‘authors’)) >>> … Read more
If you are using the django-jsonfield package, then this is simple. Say you have a model like this: from jsonfield import JSONField class User(models.Model): jsonfield = JSONField() Then to search for records with a specific username, you can just do this: User.objects.get(jsonfield__contains={‘username’:username})