Django - 更新数据库行

Question

我刚刚开始学习 django，但遇到了一个问题。我不知道如何更新 数据库行（字段）。目前，当我调用 form_valid 时，我的数据库表正在添加额外信息。

是的，我读到了这个：How to update an object from edit form in Django?

但这对我不起作用。它仍然每次都在添加更多信息。

View.py

    def form_valid(self, form, **kwargs):
        print 'heeee'
        students = Student.objects.all()
        studies = Student_in_Subgroup.objects.all()
        subgroups = Subgroup.objects.all()

        lists = self.request.POST.getlist('studs[]')

        sum = 0
        for student in students:
            for l in lists:
                if student.id == int(l):
                    for studie in studies:
                        if studie.student_Id.id == student.id:
                            for subgroup in subgroups:
                                if studie.subgroup_Id.id == subgroup.id:
                                    print student.id
                                    studentId = student.id
                                    key = subgroup.student_group_id
                                    sum = sum + 1
                                    if subgroup.number == None:
                                        continue
                                    subgroupId = studie.subgroup_Id.id
        if (self.request.POST.get('act1')=='add'):
            #problem sowhere here I THINK
            instance = get_object_or_404(Subgroup, id=subgroupId)
            form = ApplicationFormaFull1(self.request.POST or None, instance=instance)
            form.save()
            #problem sowhere here I THINK
            xxx=form['sub']
            xxx.student_group = StudentGroup.objects.get(id=key)
            xxx.number = self.request.POST.get('act2')
            xxx.type = self.request.POST.get('act3')
            xxx.stundent_count = sum
            xxx.save()
            yyy=form['stud_sub']
            yyy.subgroup_Id = Subgroup.objects.get(id=subgroupId)
            yyy.student_Id = Student.objects.get(id=studentId)
            yyy.save()
        else:
            print('no')
        return super(IndexView, self).form_valid(form)

Form.py

class FormSubgroup(forms.ModelForm):

    class Meta:
        model = Subgroup
        exclude = ['student_group','number','type','student_count']

class FormStudent_in_Subgroup(forms.ModelForm):

    class Meta:
        model = Student_in_Subgroup
        exclude = ['subgroup_Id','student_Id']

class ApplicationFormaFull1(MultiModelForm):
    form_classes = {
        'sub': FormSubgroup,
        'stud_sub': FormStudent_in_Subgroup
    }

也许有人知道解决方案

Answer 1

要编辑模型中的信息，请使用 .update。例如 Student.objects.filter(id=studentId).update(fieldname = newvalue)