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Questions tagged [manytomanyfield]

Manytomanyfield is a field of a model class in Django that defines many-to-many relationship

Manytomanyfield is a field of a model class in Django that defines many-to-many relationship.

Quote from docs about manytomanyfield database representation:

Behind the scenes, Django creates an intermediary join table to represent the many-to-many relationship. By default, this table name is generated using the name of the many-to-many field and the name of the table for the model that contains it. Since some databases don’t support table names above a certain length, these table names will be automatically truncated to 64 characters and a uniqueness hash will be used. This means you might see table names like author_books_9cdf4; this is perfectly normal. You can manually provide the name of the join table using the db_table option.

See also:

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How to add multiple objects to ManyToMany relationship at once in Django ?

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…
philgo20
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Direct assignment to the forward side of a many-to-many set is prohibited. Use emails_for_help.set() instead

I am new to Django and didn't find any reference regarding this issue. I am getting this error when i use many to many field in Django model (models.py). I guess the issue is assigning m2m field in view(views.py) from form(forms.py). How to assign…
conf
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Django migration error :you cannot alter to or from M2M fields, or add or remove through= on M2M fields

I'm trying to modify a M2M field to a ForeignKey field. The command validate shows me no issues and when I run syncdb : ValueError: Cannot alter field xxx into yyy they are not compatible types (you cannot alter to or from M2M fields, or add or…
loar
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Django Admin ManyToManyField

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…
baobee
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Show a ManyToManyField as Checkboxes in Django Admin

Is there a simple way to show a ManyToManyField as Checkboxes in Django Admin? Thanks in advance!
eos87
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How do I remove multiple objects in a ManyToMany relationship based on a filter?

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…
bunnyhero
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Django: ManyToMany filter matching on ALL items in a list

I have such a Book model: class Book(models.Model): authors = models.ManyToManyField(Author, ...) ... In short: I'd like to retrieve the books whose authors are strictly equal to a given set of authors. I'm not sure if there is a single…
iuysal
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'QuerySet' object has no attribute ERROR, trying to get related data on ManyToMany fields

i have the following models: class Tag(models.Model): tag_name = models.CharField(max_length=250) tagcat = models.ForeignKey('TagCat') class Subject(models.Model): user = models.ManyToManyField(User) tags =…
mgPePe
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In Django, how do you retrieve data from extra fields on many-to-many relationships without an explicit query for it?

Given a situation in Django 1.0 where you have extra data on a Many-to-Many relationship: class Player(models.Model): name = models.CharField(max_length=80) class Team(models.Model): name = models.CharField(max_length=40) players =…
iammichael
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Instantiate model instance with manytomany field in Django

I have a method that works, but it seems very clumsy, and I would think there is a better way to do this. I have a Model that relates a user on my site (a twitter clone for learning purposes) to a list of other users. Right now when I create a new…
Matt Phillips
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Django syncdb conflicting related_name when using inheritance and ForeignKey

This time I think it's not me being stupid but an actual conflict. I have the below code (simplified): from django.db import models class Alpha(models.Model): relation = models.ForeignKey('Delta', related_name = 'reverse_relation', blank =…
Mark
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Displaying both sides of a ManyToMany relationship in Django admin

Say I have the following models that have a many-to-many relationship: models.py: class Foo(models.Model): name = models.TextField() class Bar(models.Model): name = models.TextField() foos = models.ManyToManyField(Foo,…
Nobilis
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How can I sort by the id of a ManyToManyField in Django?

I've got a ManyToManyField in a user object and it's used to map the users that user is following. I'm trying to show a subset list of who they have most recently followed. Is there a trick in .order_by() that will allow me to sort by the id of the…
Tim Trueman
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FieldDoesNotExist: ManyToManyField has no field named None

I have two models in Django 1.8.8: class Company(models.Model): name = models.CharField(max_length=200) members = models.ManyToManyField(User) class Folder(models.Model): name = models.CharField(max_length=200) slug =…
citos88
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How to add data to ManyToMany field using Django Rest Framework?

I'm relatively new to DJango and I am looking to add data to a many-to-many field using serializers from rest framework. My Model: class IngFamily(models.Model): name=models.CharField(max_length=30, unique=True, verbose_name='ingredient…
Rijo John
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