Django - null value in column violates not-null constraint in Django Admin

Question

I'm facing an Integrity Error in Django admin while trying to add data to the database.

The traceback is as follows:

  Environment:


  Request Method: POST
  Request URL: http://127.0.0.1:8000/site/admin/SilverInningsHelpline/classified/add/

  Django Version: 1.6.4
  Python Version: 2.7.3
  Installed Applications:
  ('django_admin_bootstrapped.bootstrap3',
   'django_admin_bootstrapped',
   'django.contrib.admin',
   'django.contrib.auth',
   'django.contrib.contenttypes',
   'django.contrib.sessions',
   'django.contrib.messages',
   'django.contrib.staticfiles',
   'SilverInningsHelpline',
   'south')
  Installed Middleware:
  ('django.contrib.sessions.middleware.SessionMiddleware',
   'django.middleware.common.CommonMiddleware',
   'django.middleware.csrf.CsrfViewMiddleware',
   'django.contrib.auth.middleware.AuthenticationMiddleware',
   'django.contrib.messages.middleware.MessageMiddleware',
   'django.middleware.clickjacking.XFrameOptionsMiddleware')


  Traceback:
  File "/home/siddharth/SilverInnings/venv/local/lib/python2.7/site-packages/django/core/handlers/base.py" in get_response
    114.                     response = wrapped_callback(request, *callback_args, **callback_kwargs)
  File "/home/siddharth/SilverInnings/venv/local/lib/python2.7/site-packages/django/contrib/admin/options.py" in wrapper
    432.                 return self.admin_site.admin_view(view)(*args, **kwargs)
  File "/home/siddharth/SilverInnings/venv/local/lib/python2.7/site-packages/django/utils/decorators.py" in _wrapped_view
    99.                     response = view_func(request, *args, **kwargs)
  File "/home/siddharth/SilverInnings/venv/local/lib/python2.7/site-packages/django/views/decorators/cache.py" in _wrapped_view_func
    52.         response = view_func(request, *args, **kwargs)
  File "/home/siddharth/SilverInnings/venv/local/lib/python2.7/site-packages/django/contrib/admin/sites.py" in inner
    198.             return view(request, *args, **kwargs)
  File "/home/siddharth/SilverInnings/venv/local/lib/python2.7/site-packages/django/utils/decorators.py" in _wrapper
    29.             return bound_func(*args, **kwargs)
  File "/home/siddharth/SilverInnings/venv/local/lib/python2.7/site-packages/django/utils/decorators.py" in _wrapped_view
    99.                     response = view_func(request, *args, **kwargs)
  File "/home/siddharth/SilverInnings/venv/local/lib/python2.7/site-packages/django/utils/decorators.py" in bound_func
    25.                 return func(self, *args2, **kwargs2)
  File "/home/siddharth/SilverInnings/venv/local/lib/python2.7/site-packages/django/db/transaction.py" in inner
    371.                 return func(*args, **kwargs)
  File "/home/siddharth/SilverInnings/venv/local/lib/python2.7/site-packages/django/contrib/admin/options.py" in add_view
    1131.                 self.save_model(request, new_object, form, False)
  File "/home/siddharth/SilverInnings/venv/local/lib/python2.7/site-packages/django/contrib/admin/options.py" in save_model
    860.         obj.save()
  File "/home/siddharth/SilverInnings/venv/local/lib/python2.7/site-packages/django/db/models/base.py" in save
    545.                        force_update=force_update, update_fields=update_fields)
  File "/home/siddharth/SilverInnings/venv/local/lib/python2.7/site-packages/django/db/models/base.py" in save_base
    573.             updated = self._save_table(raw, cls, force_insert, force_update, using, update_fields)
  File "/home/siddharth/SilverInnings/venv/local/lib/python2.7/site-packages/django/db/models/base.py" in _save_table
    654.             result = self._do_insert(cls._base_manager, using, fields, update_pk, raw)
  File "/home/siddharth/SilverInnings/venv/local/lib/python2.7/site-packages/django/db/models/base.py" in _do_insert
    687.                                using=using, raw=raw)
  File "/home/siddharth/SilverInnings/venv/local/lib/python2.7/site-packages/django/db/models/manager.py" in _insert
    232.         return insert_query(self.model, objs, fields, **kwargs)
  File "/home/siddharth/SilverInnings/venv/local/lib/python2.7/site-packages/django/db/models/query.py" in insert_query
    1511.     return query.get_compiler(using=using).execute_sql(return_id)
  File "/home/siddharth/SilverInnings/venv/local/lib/python2.7/site-packages/django/db/models/sql/compiler.py" in execute_sql
    903.             cursor.execute(sql, params)
  File "/home/siddharth/SilverInnings/venv/local/lib/python2.7/site-packages/django/db/backends/util.py" in execute
    69.             return super(CursorDebugWrapper, self).execute(sql, params)
  File "/home/siddharth/SilverInnings/venv/local/lib/python2.7/site-packages/django/db/backends/util.py" in execute
    53.                 return self.cursor.execute(sql, params)
  File "/home/siddharth/SilverInnings/venv/local/lib/python2.7/site-packages/django/db/utils.py" in __exit__
    99.                 six.reraise(dj_exc_type, dj_exc_value, traceback)
  File "/home/siddharth/SilverInnings/venv/local/lib/python2.7/site-packages/django/db/backends/util.py" in execute
    53.                 return self.cursor.execute(sql, params)

  Exception Type: IntegrityError at /site/admin/SilverInningsHelpline/classified/add/
  Exception Value: null value in column "category_id" violates not-null constraint

My models are as follows:

class Categories(models.Model):
    id = models.AutoField(primary_key=True)
    type = models.CharField(max_length=300)

    def __unicode__(self):
        return self.type


class Subcategory(models.Model):
    id = models.AutoField(primary_key=True)
    parent = models.ForeignKey(Categories)
    name = models.CharField(max_length=300)

    def __unicode__(self):
        return self.name



class Classified(models.Model):
    id = models.AutoField(primary_key=True)
    name = models.CharField(max_length=256)
    contact_person = models.CharField(max_length=300)
    email = models.CharField(max_length=100)
    address = models.ForeignKey(Address)
    subcategory = models.ForeignKey(Subcategory)
    phone_number = models.BigIntegerField(max_length=20, default=0)
    image = models.ImageField(blank=True, upload_to='dynamic/img/')
    NO = 'NO'
    YES = 'YES'
    APPROVAL = ((NO, 'no'), (YES, 'yes'))
    active = models.CharField(choices=APPROVAL, default=NO, max_length=3)
    verified = models.CharField(choices=APPROVAL, default=NO, max_length=3)

    def __unicode__(self):
        return self.name

The problems arise when I try to make an entry to the Classified table from Admin.

Tried solution from here:

IntegrityError: null value in column "city_id " violates not-null constraint as it was the closest to my problem. My tables looked like this after trying the solution on that link:

class Categories(models.Model):
    id = models.AutoField(primary_key=True)
    type = models.CharField(max_length=300, unique=True, default='All', null=True)

    def __unicode__(self):
        return self.type


class Subcategory(models.Model):
    id = models.AutoField(primary_key=True)
    parent = models.ForeignKey(Categories, null=True, blank=True, default='All')
    name = models.CharField(max_length=300)

    def __unicode__(self):
        return self.name



class Classified(models.Model):
    id = models.AutoField(primary_key=True)
    name = models.CharField(max_length=256)
    contact_person = models.CharField(max_length=300)
    email = models.CharField(max_length=100)
    address = models.ForeignKey(Address)
    subcategory = models.ForeignKey(Subcategory)
    phone_number = models.BigIntegerField(max_length=20, default=0)
    image = models.ImageField(blank=True, upload_to='dynamic/img/')
    NO = 'NO'
    YES = 'YES'
    APPROVAL = ((NO, 'no'), (YES, 'yes'))
    active = models.CharField(choices=APPROVAL, default=NO, max_length=3)
    verified = models.CharField(choices=APPROVAL, default=NO, max_length=3)

    def __unicode__(self):
        return self.name

But this did not solve my problem and now I'm stuck.

Answer 1

Just add null=True in all your Fields check https://docs.djangoproject.com/en/3.1/topics/migrations/#postgresql

Answer 2

Looking at your models you shouldn't have field category_id in any of your tables. Perhaps you changed your models but did not alter tables in the database. Now when you create an entry, Django does not fill fields it doesn't know about of and this creates an error. You should remove unneeded fields from your tables. Or if it is possible you can drop the whole database and run manage.py syncdb from scratch.