Integrity Error May not be null - django

Question

I am building a website similar to a bartering website, but we are bartering Time,
I have a class Transaction, where it takes the "offer" value, deductions that value from the balance of the requesting user, and credits the value to the Offer'r.
Right now when I click on "Accept Offer" from my template I get this error
ofertoj_transaction.accepted_by may not be NULL
Stacktrace:
IntegrityError at /oferto/accept/
Environment:
Request Method: GET
Request URL: http://127.0.0.1:8000/oferto/accept/?offer_id=1&creator=2
Django Version: 1.5.4
Python Version: 2.7.4
Installed Applications:
('django.contrib.auth',
'django.contrib.contenttypes',
'django.contrib.sessions',
'django.contrib.sites',
'django.contrib.messages',
'django.contrib.staticfiles',
'django.contrib.admin',
'django.contrib.admindocs',
'django.contrib.comments',
'django.contrib.sitemaps',
'zinnia',
'tagging',
'mptt',
'south',
'registration',
'blogs',
'turtle',
'ofertoj',
'petoj',
'x',
'profiles')
Installed Middleware:
('django.middleware.common.CommonMiddleware',
'django.contrib.sessions.middleware.SessionMiddleware',
'django.middleware.csrf.CsrfViewMiddleware',
'django.contrib.auth.middleware.AuthenticationMiddleware',
'django.contrib.messages.middleware.MessageMiddleware',
'django.middleware.clickjacking.XFrameOptionsMiddleware')
Traceback:
File "/home/talisman/virt_env/tempilo/local/lib/python2.7/site-packages/Django-1.5.4-py2.7.egg/django/core/handlers/base.py" in get_response
115. response = callback(request, *callback_args, **callback_kwargs)
File "/home/talisman/virt_env/tempilo/local/lib/python2.7/site-packages/Django-1.5.4-py2.7.egg/django/views/generic/base.py" in view
68. return self.dispatch(request, *args, **kwargs)
File "/home/talisman/virt_env/tempilo/local/lib/python2.7/site-packages/Django-1.5.4-py2.7.egg/django/views/generic/base.py" in dispatch
86. return handler(request, *args, **kwargs)
File "/home/talisman/projects/tempilo/ofertoj/views.py" in get
74. accepted_by=self.request.user.id
File "/home/talisman/projects/tempilo/ofertoj/models.py" in create
59. new_transaction.save()
File "/home/talisman/virt_env/tempilo/local/lib/python2.7/site-packages/Django-1.5.4-py2.7.egg/django/db/models/base.py" in save
546. force_update=force_update, update_fields=update_fields)
File "/home/talisman/virt_env/tempilo/local/lib/python2.7/site-packages/Django-1.5.4-py2.7.egg/django/db/models/base.py" in save_base
650. result = manager._insert([self], fields=fields, return_id=update_pk, using=using, raw=raw)
File "/home/talisman/virt_env/tempilo/local/lib/python2.7/site-packages/Django-1.5.4-py2.7.egg/django/db/models/manager.py" in _insert
215. return insert_query(self.model, objs, fields, **kwargs)
File "/home/talisman/virt_env/tempilo/local/lib/python2.7/site-packages/Django-1.5.4-py2.7.egg/django/db/models/query.py" in insert_query
1675. return query.get_compiler(using=using).execute_sql(return_id)
File "/home/talisman/virt_env/tempilo/local/lib/python2.7/site-packages/Django-1.5.4-py2.7.egg/django/db/models/sql/compiler.py" in execute_sql
937. cursor.execute(sql, params)
File "/home/talisman/virt_env/tempilo/local/lib/python2.7/site-packages/Django-1.5.4-py2.7.egg/django/db/backends/util.py" in execute
41. return self.cursor.execute(sql, params)
File "/home/talisman/virt_env/tempilo/local/lib/python2.7/site-packages/Django-1.5.4-py2.7.egg/django/db/backends/sqlite3/base.py" in execute
364. six.reraise(utils.IntegrityError, utils.IntegrityError(*tuple(e.args)), sys.exc_info()[2])
File "/home/talisman/virt_env/tempilo/local/lib/python2.7/site-packages/Django-1.5.4-py2.7.egg/django/db/backends/sqlite3/base.py" in execute
362. return Database.Cursor.execute(self, query, params)
Exception Type: IntegrityError at /oferto/accept/
Exception Value: ofertoj_transaction.accepted_by may not be NULL
part of ofertoj.views.py
class TransactionView(TemplateView, LoginRequiredMixin):
template_name = "ofertoj/offer_accepted.html"
def get(self, request, *args, **kwargs):
context = self.get_context_data(**kwargs)
if self.request.GET.get("offer_id"):
oferto = Oferto.objects.get(id=self.request.GET.get("offer_id"))
if oferto.valid:
transaction = Transaction()
transaction.create(
creator=self.request.GET.get("creator"),
amount=oferto.time,
accepted_by=self.request.user.id
)
acceptor = Profile.objects.get(user=self.request.user)
acceptor.balance = acceptor.balance - oferto.time
acceptor.save()
# credit the coins to the creator
creator = Profile.objects.get(user=oferto.user)
creator.balance = creator.balance + oferto.time
creator.save()
else:
return HttpResponse("This offer is already accepted")
else:
raise Http404
return self.render_to_response(context)
Part of Ofertoj.models
class Transaction(models.Model):
creator = models.IntegerField()
amount = models.IntegerField()
accepted_by = models.IntegerField()
def __unicode__(self):
return self.id
def create(self, **kwargs):
new_transaction = Transaction(
creator = kwargs['creator'],
amount = kwargs['amount'],
accepted_by = kwargs['accepted_by']
)
new_transaction.save()
return
this line is highlited in the stacktrace
acceptor = Profile.objects.get(user=self.request.user)
ofertoj.urls
url(
regex=r"^accept/$",
view = TransactionView.as_view(),
name = "accept_offer"
),
part of my template
{% if oferto.valid and not oferto.user == request.user %}
Accept this Offer
{% endif %}
<br /><br />

Answer 1

Your ofertoj application is trying to store a Transaction object which has an accepted_by field which is NULL but your database schema does not allow this field to be NULL.
Check this code:
transaction.create(
creator=self.request.GET.get("creator"),
amount=oferto.time,
accepted_by=self.request.user.id
)
and the code of transaction.create.
One possibility: if your user is not logged in then self.request.user.id will be None, and this translates to NULL in the database. I do not see anything in your code that requires the user to be logged in.

Answer 2

it was an issue with unicode method in the Profile model
and since, the balance was default null