Solution for Django ValueError at /updatestudent/3 Cannot assign “‘1′”: “Student.class_id” must be a “Class” instance
is Given Below:
ValueError at /updatestudent/3 Cannot assign “‘1′”: “Student.class_id” must be a “Class” instance. This error comes when I am trying to update my student model. when I am updating username also than it doesn’t throw any error but if I am not updating username than only this throwing this error
Any help is appericiated.
models.py
class CustomUser(AbstractUser):
user_type_data = ((1,'HOD'),(2,'Staff'),(3,'Student'))
user_type = models.CharField(default=1, choices=user_type_data, max_length=10)
class Student(models.Model):
id = models.AutoField(primary_key=True)
admin = models.OneToOneField(CustomUser, on_delete=models.CASCADE)
gender = models.CharField(default=1, choices=gender_type, max_length=10)
profile = models.ImageField(upload_to='student/profile-images/%y/%m/%d/', default="student/profile-images/default.jpg", blank=False, null=False)
address = models.TextField()
class_id = models.ForeignKey(Class, on_delete=models.CASCADE, default=1)
created_at = models.DateTimeField(auto_now_add=True)
updated_at = models.DateTimeField(auto_now_add=True)
objects = models.Manager()
def full_name(self):
return self.admin.first_name+' '+self.admin.last_name
def __str__(self):
return self.admin.username
class Session(models.Model):
id = models.AutoField(primary_key=True)
session_start= models.IntegerField()
session_end = models.IntegerField()
objects = models.Manager()
def __str__(self):
return f'{self.session_start} {self.session_end}'
class Course(models.Model):
id = models.AutoField(primary_key=True)
name = models.CharField(max_length=255)
created_at = models.DateTimeField(auto_now_add=True)
updated_at = models.DateTimeField(auto_now_add=True)
objects = models.Manager()
def __str__(self):
return self.name
class Class(models.Model):
id = models.AutoField(primary_key=True)
course = models.ForeignKey(Course, on_delete=models.CASCADE)
branch = models.CharField(default="CSE", choices=branch_data, max_length=40)
year = models.CharField(default="First Year", choices=year_data, max_length=15)
session = models.ForeignKey(Session, on_delete=models.CASCADE)
created_at = models.DateTimeField(auto_now_add=True)
updated_at = models.DateTimeField(auto_now_add=True)
objects = models.Manager()
def __str__(self):
return f'{self.course} {self.branch} {self.year} {self.session}'
def name(self):
return f'{self.course} {self.branch} {self.year} {self.session}'
forms.py
from django import forms
from django.contrib.auth.models import User
from django.contrib.auth.forms import UserChangeForm, UserCreationForm
from django.db.models import fields
from .models import (AdminHOD, Staff, Student, Class,
CustomUser, Course, Session, Attendance,
ExamType, Exam, Subject)
from .models import branch_data, year_data
gchoice = (('1','Male'),('2','Female'))
sesschoice = tuple((i.id, i.id) for i in Session.objects.all())
courchoice = tuple((i.id,i) for i in Course.objects.all())
choice_exam = tuple((i.id,i.name) for i in ExamType.objects.all())
all_class = tuple((i.id, i.name) for i in Class.objects.all())
class UserUpdateForm(UserChangeForm):
email = forms.EmailField()
class Meta:
model = User
fields = ['first_name', 'last_name', 'username', 'email']
class StudentUpdateForm(forms.ModelForm):
gender = forms.ChoiceField(choices=gchoice)
address = forms.CharField()
class_id = forms.ChoiceField(choices=all_class)
class Meta:
model = Student
fields = ['gender', 'class_id', 'address']
views.py
if request.method=='POST':
uform = UserUpdateForm(request.POST)
sform = StudentUpdateForm(request.POST)
if uform.is_valid():
address = request.POST.get('address')
username = request.POST.get('username')
clas = Class.objects.get(id=request.POST['class_id'])
email = request.POST.get('email')
gender = request.POST.get('gender')
print(clas)
try:
student = Student.objects.get(id=id)
user = student.admin
user.username = username
user.email = email
user.save()
student.address = address
student.gender = str(gender)
student.class_id = clas
student.updated_at = datetime.datetime.now()
student.save()
messages.success(request,'Student successfully Updated.')
return redirect('/managestudent')
except:
messages.error(request,'Student has not been Updated due to some technical issues.')
return render(request, 'cmsapp/hod/studentupdate.html', {'uform':uform,'sform':sform})
else:
messages.error(request,sform.errors)
return render(request, 'cmsapp/hod/studentupdate.html', {'uform':uform,'sform':sform})
else:
uform = UserUpdateForm(instance=Student.objects.get(id=id).admin)
sform = StudentUpdateForm(instance=Student.objects.get(id=Student.objects.get(id=id).id))
return render(request, 'cmsapp/hod/studentupdate.html', {'uform':uform,'sform':sform})
studentupdate.html
<h3>Update Student</h3>
<form action="" method="POST" class="form-group">
{% csrf_token %}
{{uform}}
{{sform}}
<button type="submit">Update Student</button>
</form>
</div>
traceback
Traceback (most recent call last):
File "C:UsersAkash Deep SaingarDesktopMySitevenvlibsite-packagesdjangocorehandlersexception.py", line 47, in inner
response = get_response(request)
File "C:UsersAkash Deep SaingarDesktopMySitevenvlibsite-packagesdjangocorehandlersbase.py", line 181, in _get_response
response = wrapped_callback(request, *callback_args, **callback_kwargs)
File "C:UsersAkash Deep SaingarDesktopMySiteCollegeErpcmsapphodviews.py", line 176, in update_student
messages.error(request,sform.errors)
File "C:UsersAkash Deep SaingarDesktopMySitevenvlibsite-packagesdjangoformsforms.py", line 172, in errors
self.full_clean()
File "C:UsersAkash Deep SaingarDesktopMySitevenvlibsite-packagesdjangoformsforms.py", line 376, in full_clean
self._post_clean()
File "C:UsersAkash Deep SaingarDesktopMySitevenvlibsite-packagesdjangoformsmodels.py", line 400, in _post_clean
self.instance = construct_instance(self, self.instance, opts.fields, opts.exclude)
File "C:UsersAkash Deep SaingarDesktopMySitevenvlibsite-packagesdjangoformsmodels.py", line 63, in construct_instance
f.save_form_data(instance, cleaned_data[f.name])
File "C:UsersAkash Deep SaingarDesktopMySitevenvlibsite-packagesdjangodbmodelsfields__init__.py", line 891, in save_form_data
setattr(instance, self.name, data)
File "C:UsersAkash Deep SaingarDesktopMySitevenvlibsite-packagesdjangodbmodelsfieldsrelated_descriptors.py", line 215, in __set__
raise ValueError(
Exception Type: ValueError at /updatestudent/3
Exception Value: Cannot assign "'1'": "Student.class_id" must be a "Class" instance.
In StudentUpdateForm, try to change the class_id field to:
class_id = forms.ModelChoiceField(queryset=Class.objects.all())