django-orm

Is it possible to replicate this kind of specific sql ordering in the django ORM: order by (case when id = 5 then 1 when id = 2 then 2 when id = 3 then 3 when id = 1 then 4 when id = 4 then 5 end) asc ? You could do it w/ extra() or more plain raw() , but they can not work well w/ more complex situation. qs.extra(select={'o':'(case when id=5 then 1 when id=2 then 2 when id=3 then 3 when id=1 then 4 when id=4 then 5 end)', order_by='o'} YourModel.raw('select ... order by (case ...)') For your code, condition set is very limited, you could sort in Python easily. Since Django 1.8 you have

I've made a model (models.py): class opetest(models.Model): name = models.CharField(max_length=200) author = models.ForeignKey(User, related_name='author') description = models.TextField(u'Test description', help_text = u'Some words about quiz') pub_date = models.DateTimeField('date published', blank=False) vacancies = models.ManyToManyField(Vacancy, blank=True) students = models.ManyToManyField(User, blank=True, related_name='opetests') #This field I want to edit on "User change page" estimate = models.IntegerField(default = 0, help_text = u'Estimate time in hours. \'0\' - unlimited') then I

If my Models look like: class Publisher(models.Model): pass class Book(models.Model): publisher = models.ForeignKey(Publisher) class Page(models.Model): book = models.ForeignKey(Book) and I would like to get the queryset for Publisher I do Publisher.object.all() . If then want to make sure to prefetch I can do: Publisher.objects.all().prefetch_related('book_set')` My questions are: Is there a way to do this prefetching using select_related or must I use prefetch_related ? Is there a way to prefetch the page_set ? This does not work: Publisher.objects.all().prefetch_related('book_set', 'book

I have these models: def Foo(Models.model): size = models.IntegerField() # other fields def is_active(self): if check_condition: return True else: return False def Bar(Models.model): foo = models.ForeignKey("Foo") # other fields Now I want to query Bars that are having active Foo's as such: Bar.objects.filter(foo.is_active()) I am getting error such as SyntaxError at / ('non-keyword arg after keyword arg' How can I achieve this? You cannot query against model methods or properties. Either use the criteria within it in the query, or filter in Python using a list comprehension or genex. You

In Django, what's the difference between the following two: Article.objects.values_list('comment_id', flat=True).distinct() vs Article.objects.values('comment_id').distinct() My goal is to get a list of unique comment ids under each Article . I've read the documentation (and in fact have used both approaches). The results overtly seem similar. The values() method returns a QuerySet containing dictionaries: <QuerySet [{'comment_id': 1}, {'comment_id': 2}]> The values_list() method returns a QuerySet containing tuples: <QuerySet [(1,), (2,)]> If you are using values_list() with a single field,

I'm struggling getting my head around the Django's ORM. What I want to do is get a list of distinct values within a field on my table .... the equivalent of one of the following: SELECT DISTINCT myfieldname FROM mytable (or alternatively) SELECT myfieldname FROM mytable GROUP BY myfieldname I'd at least like to do it the Django way before resorting to raw sql. For example, with a table: id, street, city 1, Main Street, Hull 2, Other Street, Hull 3, Bibble Way, Leicester 4, Another Way, Leicester 5, High Street, Londidium I'd like to get: Hull, Leicester, Londidium. Say your model is 'Shop'

I have an array field in my PostrgreSQL database of type text. Is there a way to map this into a Django model ? You might want to look into django-dbarray on github. It adds support for postgresql array fields. I haven't used it before, but it looks like you just need to do: from django.db import model import dbarray class ProfilingTestRun(models.Model): function = models.CharField(max_length=64) runtimes = dbarray.FloatArrayField() One of the other nice options is http://django-orm.readthedocs.org/ --- a library that adds bindings to many native postgres types. Main drawback of django-orm is