manytomanyfield

问题 Searched everywhere but couldn't find anything even though it feels so simple. So basically i have two classes in my models.py class Restaurant(models.Model): restaurant_title = models.CharField(max_length=30) location = CountryField(null=True, blank_label='(select country)') first_purchase_discount = models.BooleanField(default=False) updated = models.DateTimeField(auto_now=True) slug = models.SlugField(max_length=30, unique=True) def save (self, *args, **kwargs): self.slug = slugify(self

问题 this is the representation of my models: class B(models.Model): """I'm a dummy model, so doesn't pay atention of what I do""" name = models.CharField(max_length=250) class A(models.Model): name = models.CharField(max_length=250) many_b = models.ManyToManyField(B) Now, suppose I have a list of B objects. And a single A object that will be related to that B s. Something like this: a = A.objects.get(id=1) list_of_b = [B<name='B1'>,B<name='B2'>,B<name='B3'>,] The way I relate them now is this:

问题 I am having this weird problem accessing ManyToManyField . I have following models. class Link(models.Model): title = models.CharField(max_length = 200) url = models.URLField(unique = True) tags = models.ManyToManyField(Tag) creation_date = models.DateTimeField(auto_now_add = True) user = models.ForeignKey(User) likes = models.ManyToManyField(User, related_name = "%(app_label)s_%(class)s_user_likes") dis_likes = models.ManyToManyField(User, related_name = "%(app_label)s_%(class)s_user_dis

问题 Is there a simple way to show a ManyToManyField as Checkboxes in Django Admin?? Any suggestions? 回答1: From this answer it seems like it is possible to use ModelAdmin.formfield_overrides to override the ManyToManyField to use CheckBoxSelectMultiple: from django.db import models from django.contrib import admin from django.forms import CheckboxSelectMultiple class MyModelAdmin(admin.ModelAdmin): formfield_overrides = { models.ManyToManyField: {'widget': CheckboxSelectMultiple}, } I haven't

问题 How can I store history of ManyToManyField using django-simple-history. I used HistoricalRecords with attribute m2m_filds but it is throwing error: unexpected keyword argument 'm2m_fields' 回答1: I'm macro1 on GitHub, and I guess de facto maintainer of django-simple-history. From your question it seems that you're just asking about general ManyToManyField support compared with other fields. The short answer is that we do not currently support it. ManyToManyFields actually create an in-between

问题 Suppose i have : class Album(models.Model): photos = models.ManyToManyField('myapp.Photo') photo_count = models.IntegerField(default = 0) class Photo(models.Model): photo = models.ImageField(upload_to = 'blahblah') What is want is, everytime i call .add() method, increment the photo_count on Album class, so i'm thinking to override .add() method. The problem is, i can't import the .add() 's class since it is inside a method, so it is like def->class->def . So is there anyway to override .add(

问题 Suppose i have : class Album(models.Model): photos = models.ManyToManyField('myapp.Photo') photo_count = models.IntegerField(default = 0) class Photo(models.Model): photo = models.ImageField(upload_to = 'blahblah') What is want is, everytime i call .add() method, increment the photo_count on Album class, so i'm thinking to override .add() method. The problem is, i can't import the .add() 's class since it is inside a method, so it is like def->class->def . So is there anyway to override .add(

问题 Given these two Models: class Item(models.Model): timestamp = models.DateTimeField() class Source(models.Model): items = models.ManyToManyField(Item, related_name="sources") I can find all of a Source's Items before a given time using this: source.items.filter(timestamp__lte=some_datetime) How do I efficiently remove all of the items that match that query? I suppose I could try something like this: items_to_remove = list(source.items.filter(timestamp__lte=some_datetime)) source.items.remove(

问题 Based on the Django doc, I should be able to pass multiple objects at once to be added to a manytomany relationship but I get a * TypeError: unhashable type: 'list' when I try to pass a django queryset casted in a list. Passing a Queryset or a ValuesListQueryset seems to fail also. Is there a better way than use a for loop ? 回答1: Use: object.m2mfield.add(*items) as described in the documentation: add() accepts an arbitrary number of arguments, not a list of them. add(obj1, obj2, obj3, ...) To

问题 Based on the Django doc, I should be able to pass multiple objects at once to be added to a manytomany relationship but I get a * TypeError: unhashable type: 'list' when I try to pass a django queryset casted in a list. Passing a Queryset or a ValuesListQueryset seems to fail also. Is there a better way than use a for loop ? 回答1: Use: object.m2mfield.add(*items) as described in the documentation: add() accepts an arbitrary number of arguments, not a list of them. add(obj1, obj2, obj3, ...) To