How to limit manytomanyfields on a model ?

Posted by Tom on Stack Overflow See other posts from Stack Overflow or by Tom
Published on 2010-04-27T13:45:02Z Indexed on 2010/05/14 0:54 UTC
Read the original article Hit count: 271

Filed under:

django

|

manytomanyfield

I would like to check that I get not more than 3 relations set on a manytomanyfield.

I tried on the clean method to do this :

if self.tags.count()>3:
  raise ValidationError(_(u'You cannot add more than 3 tags'))

But self.tags returns not the current updates... only saved objects.

Do you have an idea to access to them ?

Thanks

© Stack Overflow or respective owner

Related posts about django

Overriding the save() method of a model that uses django-mptt

as seen on Stack Overflow - Search for 'Stack Overflow'
I've been using django-mptt in my project for a while now, it's fabulous. Recently, I've found a need to override a model's save() method that uses mptt, and I'm getting an error when I try to save a new instance of that model: Exception Type: ValueError at /admin/scrivener/page/add/ Exception Value:… >>> More
Where is meta.local_fields set in django.db.models.base.py ?

as seen on Stack Overflow - Search for 'Stack Overflow'
I'm getting the error: Exception Value: (1110, "Column 'about' specified twice") As I was reviewing the Django error page, I noticed that the customizations the model User, seem to be appended to the List twice. This seems to be happening here in django/db/model/base.py in base_save(): values… >>> More
Deploying Django on EC2 using Bitnami Djangostack: WSGI script cannot be loadded

as seen on Stack Overflow - Search for 'Stack Overflow'
I've been struggling to deploy Django application on Amazon EC2 using Bitnami Djangostack for the last couple of days. When I go to http://dewey.io I see the default bitnami page (/opt/bitnami/apache2/htdocs/index.html), however, when I open http://dewey.io/portnoy, I get 'Internal Server Error'… >>> More
Internal Server Error with mod_wsgi [django] on windows xp

as seen on Stack Overflow - Search for 'Stack Overflow'
when i run development server it works very well, even an empty project runing in mod_wsgi i have no problem but when i want to put my own project i get an Internal Server Error (500) in my apache conf i put WSGIScriptAlias /codevents C:/django/apache/CODEvents.wsgi <Directory "C:/django/apache"> Order… >>> More
Internal Server Error with mod_wgsi [django] on windows xp

as seen on Stack Overflow - Search for 'Stack Overflow'
when i run development server it works very well, even an empty project runing in mod_wsgi i have no problem but when i want to put my own project i get an Internal Server Error (500) in my apache conf i put WSGIScriptAlias /codevents C:/django/apache/CODEvents.wsgi <Directory "C:/django/apache"> Order… >>> More

Related posts about manytomanyfield

Show models.ManyToManyField as inline, with the same form as models.ForeignKey inline

as seen on Stack Overflow - Search for 'Stack Overflow'
I have a model similar to the following (simplified): models.py class Sample(models.Model): name=models.CharField(max_length=200) class Action(models.Model): samples=models.ManyToManyField(Sample) title=models.CharField(max_length=200) description=models.TextField() Now… >>> More
ManyToManyField "table exist" error on syncdb

as seen on Stack Overflow - Search for 'Stack Overflow'
When I include a ModelToModelField to one of my models the following error is thrown. Traceback (most recent call last): File "manage.py", line 11, in <module> execute_manager(settings) File "/Library/Python/2.6/site-packages/django/core/management/__init__.py", line 362, in execute_manager … >>> More
Alternate widgets and logic for ManyToManyField with Django forms

as seen on Stack Overflow - Search for 'Stack Overflow'
In my Django project, I have a simple ticket system. When creating a ticket, certain users have the ability to assign the ticket to other users, and to email the ticket to other users as well (this is used as an FYI for those users, so they're aware of the ticket, even though it's not assigned to… >>> More
Django show manytomanyfield on form when definition is on other model

as seen on Stack Overflow - Search for 'Stack Overflow'
Hi I have the definition for my manytomany relationship on one model but want to display the field on a form for the other model. How do I do this? for example: # classes class modelA(models.Model): name = models.CharField(max_length=300) manytomany = models.ManyToManyField(modelA) class… >>> More
Django filters - Using an AllValuesFilter (with a LinkWidget) on a ManyToManyField

as seen on Stack Overflow - Search for 'Stack Overflow'
This is my first Stack Overflow question, so please let me know if I do anything wrong. I wish to create an AllValues filter on a ManyToMany field using the wonderful django-filters application. Basically, I want to create a filter that looks like it does in the Admin, so I also want to use the LinkWidget… >>> More