Short description: given a queryset myQueryset, how do I select max("myfield") without actually retrieving all rows and doing max in python? The best I can think of is max([r["myfield"] for r in myQueryset.values("myfield")]), which isn't very good if there are millions of rows. Long description: Say I have two models in my Django app,...
Hello, I have this join: lawyers = Lawyer.objects.filter(last__iexact=last_name).filter(first__icontains=first_name) This is the site If you try Last Name: Abbas and First Name: Amr it tells you that amr abbas has 1 schoolmates. But if you try First name only it says that there are no lawyers in the database called amr (obviously t...
Assume I have a such model: class Foo(models.Model): name = models.CharField("ad",max_length=25) type = models.ForeignKey(Type) So at the database I have Foo objects with same name field but different types ie: name type A 1 A 2 B 1 C 2 A 3 B 3 I will use this information inorder to generate a html s...
I am not sure if the title makes any sense but here is the question. Context: I want to keep track of which students enter and leave a classroom, so that at any given time I can know who is inside the classroom. I also want to keep track, for example, how many times a student has entered the classroom. This is a hypothetical example tha...
I have a queryset with a few million records. I need to update a Boolean Value, fundamentally toggle it, so that in the database table the values are reset. What's the fastest way to do that? I tried traversing the queryset and updating and saving each record, that obviously takes ages? We need to do this very fast, any suggestions? ...
I have a custom property on my Django model that returns the full name of a Person: class Person(models.Model): first_name = models.CharField(max_length=30) last_name = models.CharField(max_length=30) def _get_full_name(self): return "%s %s" % (self.first_name, self.last_name) full_name = property(_get_full_name) When I create ...
I'm trying to find a way to implement both a custom QuerySet and a custom Manager without breaking DRY. This is what I have so far: class MyInquiryManager(models.Manager): def for_user(self, user): return self.get_query_set().filter( Q(assigned_to_user=user) | Q(assigned_to_group__in=...
How can I retrieve the last record in a certain queryset? ...
I want to retrieve the most recently added element and if there is none at all, assign some default values such as: query = X.objects.filter(name="aa",type="b")[0] if query: resultname =query.name resulttype = query.type else: resultname = "a default name" resulttype = "a default type" This is not working as it will ra...
(Please let me know if this is completely absurd, that is probably a reason why I haven't found anything on this.) This story has two models Ranking and Artist, Ranking is generically related to Artist (object_id, content_type... the whole shebang). I have a list of objects returned by Ranking.objects.values_list() ordered by a certain...
I'd like to use simplejson to serialize a Django model. Django's serializer doesn't support dictionaries... and simplejson doesn't support Django Querysets. This is quite a conundrum. In the model there's sponsors that have a Foreign Key to sponsor level, I'm trying to group all the sponsors that belong to a certain sponsor level togeth...
Hello, I'm a Django newbie, so please forgive me if this is a stupid question. I have a search form that has multiple fields on it. I only wish to filter my queryset by those fields submitted that aren't empty. How do I do that? I'm aware you can chain querysets and Q objects together, but I don't know how to eliminate empty key/value p...
I'm using Django 1.1 with MySQL as the database. I have a model similar to the following: class Review(models.Model): venue = models.ForeignKey(Venue, db_index=True) review = models.TextField() datetime_created = models.DateTimeField(default=datetime.now) I'd like to query the database to get the total number of reviews...
I've been able to do this through the django environment shell, but hasn't worked on my actual site. Here is my model: class ShoeReview(models.Model): def __unicode__(self): return self.title title = models.CharField(max_length=200) slug = models.SlugField(unique=True) keywords = models.Te...
I need some help putting together this query in Django. I've simplified the example here to just cut right to the point. MyModel(models.Model): created = models.DateTimeField() user = models.ForeignKey(User) data = models.BooleanField() The query I'd like to create in English would sound like: Give me every record that w...
I have BlogEntry model, which has two special fields : "publication_date"(timestamp), "sticky"(boolean). i need to get them in order by "publication_date", and group by "sticky" field that have to be first in query set. what i try to get: [ <BlogEntry:"05.03.2010 sticky:1">, <BlogEntry:"04.03.2010 sticky:1">, <BlogEntry:"03.03.2010 st...
Is there a difference between filter and exclude in django? If I have self.get_query_set().filter(modelField=x) and I want to add another criteria, is there a meaningful difference between to following two lines of code? self.get_query_set().filter(user__isnull=False, modelField=x) self.get_query_set().filter(modelField=x).exclude(u...
Given the following Contribution model: class Contribution(models.Model): start_time = models.DateTimeField() end_time = models.DateTimeField(null=True) is it possible, using the Django database API, to reproduce the following SQL statement? SELECT SUM(end_time - start_time) AS total_duration FROM contribution; I've figured...
I have two tables, one "Company" and one "Employee": class Company(models.Model): name = models.CharField(max_length=60) class Employee(models.Model): name = models.CharField(max_length=60) company = models.ForeignField(Company) And I want to list every Employee in a table, with the Company next to it. Which is simple eno...
I would like to implement a search function in a django blogging application. The status quo is that I have a list of strings supplied by the user and the queryset is narrowed down by each string to include only those objects that match the string. See: if request.method == "POST": form = SearchForm(request.POST) if fo...