Question

我正在尝试实现“学生已连接到用户”，“作业已连接到学生”。

Django迁移问题。

django.db.utils.IntegrityError：唯一约束失败：Student_student.user_id

models.py文件

models.py

from django.db import models
from django.utils import timezone
from django.core.validators import MinLengthValidator,MaxValueValidator
from django.contrib.auth.models import User


# Create your models here.
class Student(models.Model):
    user = models.OneToOneField(User, on_delete=models.CASCADE,primary_key=True,default=111111)
    student_name = models.CharField(max_length = 20)
    student_address = models.TextField()
    student_bloodgrp = models.CharField(max_length = 3)
    #This will be used to upload image of student in some directory not in database
    student_image = models.ImageField(upload_to ='profile_pic/')
    student_mail = models.EmailField()
    student_dob = models.DateTimeField()
    student_branch = models.CharField(max_length = 3)
    student_reg_no = models.IntegerField(validators=[MaxValueValidator(9999999999)])
    student_mob = models.IntegerField(validators=[MaxValueValidator(9999999999)])
    student_sem = models.IntegerField(validators=[MaxValueValidator(8)])
    student_accom = models.CharField(max_length = 1) # y for boarders & n for non-boarders

    class Meta:
        verbose_name_plural = "Students"







class Subjects(models.Model):
    subjectName = models.CharField(max_length=100,primary_key=True)
    branch = models.CharField(max_length=100)
    semester = models.IntegerField()

    class Meta:
        verbose_name_plural = "Subjects"

    def __str__(self):
        return self.subjectName+"--"+self.branch+"--"+str(self.semester)


class Assignments(models.Model):
    student = models.ForeignKey(Student,on_delete=models.DO_NOTHING)
    subject = models.ForeignKey(Subjects,on_delete=models.DO_NOTHING)
    document = models.FileField(upload_to='assignments/')

    class Meta:
        verbose_name_plural = "Assignments"



    def __str__(self):
        return self.student.student_name

forms.py此处

forms.py  


from django import forms
from .models import Assignments


class AssignmentForm(forms.ModelForm):
    class Meta:
        model = Assignments
        fields = ('student', 'document','subject' )


    ******************************************************************
views.py here 

views.py

from django.shortcuts import render,redirect
from .forms import AssignmentForm
from django.contrib.auth.decorators import login_required

def mainStudent(request):

    return render(request,'Student/main.html')


def masterStudent(request):

    return render(request,'Student/master.html')



@login_required
def uploadAssignment(request):
    if request.method == 'POST':
        form = AssignmentForm(request.POST, request.FILES)
        if form.is_valid():
            form.save()
            return redirect('student-main')
    else:
        form =AssignmentForm()


    return render(request, 'Student/upload_Assignment.html', {
        'form': form
    })

我希望将学生用户ID和密码连接到User。将第一个字段分配为学生。

Answer 1

您正在为OneToOneField使用默认值，这实际上没有任何意义。使用OneToOneField意味着每个Student只能有一个User记录。该默认值将在第一次创建Student而没有User时起作用，但是下次它将失败，并出现唯一的约束错误。迁移可能正在尝试添加多个Student记录而没有User。

您应该删除默认值并检查数据，以了解没有Student的{{1}}的来源。或者，您可以将User字段设置为可空并删除user，以便Django创建一个隐式的primary_key=True主键：

id

唯一约束失败：Student_assignments.user_id

1 个答案: