django-models

how to delete old image when update ImageField?

hi using Django to create a stock photo site, i have a ImageField in my model, the problem is that when the user update the image field, the original image file isn't deleted from the hard disk. how can I make to delete those images after an update? Thanks! ...

Is there a way to simplify this Django query?

accepted_bids = Bid.objects.filter(shipment__user=u, status='acc').select_related('shipment') completed_shipments = [] for b in accepted_bids: completed_shipments.append(b.shipment) vehicles_shipped = [] for s in completed_shipments: vehicles_shipped.extend(s.items.all()) In the end, I want a list of shipped vehicles. A vehicle...

Django - 2 fields unique together

Suppose, I want to record say poll choices by users everyday. In this case, i have a table named vote which has columns poll , choice and user-id . So how can i out the constraint (maybe in the django models or wherever possible) that poll and user-id both should not be the same for any entry but like the same user can vote for various d...

Cannot assign - must be a "UserProfile" instance

I have a class UserProfile defined which takes the default user as a foreign key. Now another class A has a foreign key to UserProfile. So for saving any instance in class A, how do i give it the userprofile object. Also, does making a class UserProfile mean that class user is still used and class UserProfile is just some other table?...

Django admin causes high load for one model...

In my Django admin, when I try to view/edit objects from one particular model class the memory usage and CPU rockets up and I have to restart the server. I can view the list of objects fine, but the problem comes when I click on one of the objects. Other models are fine. Working with the object in code (i.e. creating and displaying) is o...

Django: query spanning multiple many-to-many relationships

I've got some models set up like this: class AppGroup(models.Model): users = models.ManyToManyField(User) class Notification(models.Model): groups_to_notify = models.ManyToManyField(AppGroup) The User objects come from django's authentication system. Now, I am trying to get all the notifications pertaining to the groups that the...

Left Join with a OneToOne field in Django

I have 2 tables, simpleDB_all and simpleDB_some. The "all" table has an entry for every item I want, while the "some" table has entries only for some items that need additional information. The Django models for these are: class all(models.Model): name = models.CharField(max_length=40) important_info = models.CharField(max_lengt...

Extending the User model with custom fields in Django

I am trying to extend the User model so that I can add my own custom fields but I keep getting an error stating: 'NoneType' object has no attribute '_default_manager' whenever I try to use user.get_profile() to add values to the custom field i.e. whenever I use it like so: user = User.objects.create_user(username, email...

inverse relation to multiple inheriting classes in django

Here are my schematic models: class Law(models.Model): ... class Bill(models.Model): ... # data for a proposed law, or change of an existing law class PrivateBill(Bill): ... # data for a Bill that was initiated by a parliament member class GovernmentBill(Bill): ... # data for a Bill that was initiated by the governme...

Display/Edit fields across tables in a Django Form

I have 2 tables/models, which for all practical purposes are the same as the standard Author/Book example, but with the additional restriction that in my application each Author can only write 0 or 1 books. (eg, the ForeignKey field in the Book model is or can be a OneToOneField, and there may be authors who have no corresponding book in...

How do I tell Django to use MySql from a WAMP install?

I've had Django running with Sqlite for a while. I then installed WAMP, and I now want to get ready for a production run, and would like to switch to MySql. Is there a straightforward way of telling it about the MySql instance that is running with WAMP? ...

How can I limit ModelAdmin queryset to user-editable items when using object permissions?

I'm trying to implement Florian's object permissions system from his article on Django Advent, but I'm running into an issue trying to limit the queryset returned to only items the user has permission to edit/view. Florian mentions it in his section on wrapping the admin, but skips over it. I can't see a good way to filter the queryset. ...

Making only a part of model field available in Django

Hello I have a such model: GENDER_CHOICES = ( ('M', 'Male'), ('F', 'Female') ) class Profile(models.Model): user = models.ForeignKey(User) gender = models.CharField(max_length=1, choices=GENDER_CHOICES) class FrontPage(models.Model): female = models.ForeignKey(User,related_name="female") male = models.ForeignKey(User,re...

verbose_name for a model's method

How can I set a verbose_name for a model's method, so that it might be displayed in the admin's change_view form? example: class Article(models.Model): title = models.CharField(max_length=64) created_date = models.DateTimeField(....) def created_weekday(self): return self.created_date.strftime("%A") in admin.py: ...

Order in many to many relation in Django model

I am writing a small website to store the papers I have written. The relation papers<-> author is important, but the order of the name of the authors (which one is First Author, which one is second order, and so on) is also important. I am just learning Django so I don't know much. In any case so far I have done: from django.db import ...

Django model fields getter / setter

Hi, is there something like getters and setters for django model's fields? For example, I have a text field in which i need to make a string replace before it get saved (in the admin panel, for both insert and update operations) and make another, different replace each time it is read. Those string replace are dynamic and need to be d...

why are read only form fields in django a bad idea?

I've been looking for a way to create a read-only form field and every article I've found on the subject comes with a statement that "this is a bad idea". Now for an individual form, I can understand that there are other ways to solve the problem, but using a read only form field in a modelformset seems like a completely natural idea. ...

django sync db question

In django models say this model exist in details/models.py class OccDetails(models.Model): title = models.CharField(max_length = 255) occ = models.ForeignKey(Occ) So when sync db is made the following fields get created and later to this of two more fields are added and sync db is made the new fields doesnt get cre...

Doing a count over a filter query efficiently in django

Hello, Django newbie here, I need to do a count over a certain filter in a django model. If I do it like so: my_model.objects.filter(...).count() I'm guessing it does the SQL query that retrieves all the rows and only afterwards does the count. To my knowledge it's much more efficient to do the count without retrieving those rows like so...

Post and Comment with the same Model.

I have created a simple project where everyone can create one or more Blog. I want to use this models for Post and for Comment: class Post_comment(models.Model): content_type = models.ForeignKey(ContentType) object_id = models.PositiveIntegerField(_('object ID')) content_object = generic.GenericForeignKey() # Hierarchy...