Python 如何更新django表单集？

我不熟悉Django和web开发。我正在使用表单集将数据保存到数据库中。创建部分工作得很好，但当我尝试使用表单集更新数据库中的现有数据时，会遇到问题

以下是相关的代码片段：

型号：

from django.db import models

class GradingSchemeName(models.Model):
    name = models.CharField(max_length=250, null=False, blank=False, unique=True)

class GradingScheme(models.Model):
    scheme_name = models.ForeignKey(to=GradingSchemeName, on_delete=models.CASCADE)
    grade = models.CharField(max_length=250, null=False, blank=False)
    score_range_begin = models.SmallIntegerField()
    score_range_end = models.SmallIntegerField()

    class Meta:
        unique_together = ('scheme_name', 'grade',)

from django.forms import ModelForm, inlineformset_factory

GradeFormSet = inlineformset_factory(
    parent_model=GradingSchemeName, model=GradingScheme,
    fields=['scheme_name', 'grade', 'score_range_begin', 'score_range_end'],
    extra=10, max_num=100, can_delete=False
)

# Passing the pre-filled form for rendering. For the sake of illustration, I have hardcoded the `id=1`:
instance = GradingSchemeName.objects.get(id='1')        
context['grade_formset'] = GradeFormSet(instance=instance)

# checking the request data from the post(request) on form submission:
grades_formset = GradeFormSet(request.POST, instance=instance)

表格：

from django.db import models

class GradingSchemeName(models.Model):
    name = models.CharField(max_length=250, null=False, blank=False, unique=True)

class GradingScheme(models.Model):
    scheme_name = models.ForeignKey(to=GradingSchemeName, on_delete=models.CASCADE)
    grade = models.CharField(max_length=250, null=False, blank=False)
    score_range_begin = models.SmallIntegerField()
    score_range_end = models.SmallIntegerField()

    class Meta:
        unique_together = ('scheme_name', 'grade',)

from django.forms import ModelForm, inlineformset_factory

GradeFormSet = inlineformset_factory(
    parent_model=GradingSchemeName, model=GradingScheme,
    fields=['scheme_name', 'grade', 'score_range_begin', 'score_range_end'],
    extra=10, max_num=100, can_delete=False
)

# Passing the pre-filled form for rendering. For the sake of illustration, I have hardcoded the `id=1`:
instance = GradingSchemeName.objects.get(id='1')        
context['grade_formset'] = GradeFormSet(instance=instance)

# checking the request data from the post(request) on form submission:
grades_formset = GradeFormSet(request.POST, instance=instance)

视图：

from django.db import models

class GradingSchemeName(models.Model):
    name = models.CharField(max_length=250, null=False, blank=False, unique=True)

class GradingScheme(models.Model):
    scheme_name = models.ForeignKey(to=GradingSchemeName, on_delete=models.CASCADE)
    grade = models.CharField(max_length=250, null=False, blank=False)
    score_range_begin = models.SmallIntegerField()
    score_range_end = models.SmallIntegerField()

    class Meta:
        unique_together = ('scheme_name', 'grade',)

from django.forms import ModelForm, inlineformset_factory

GradeFormSet = inlineformset_factory(
    parent_model=GradingSchemeName, model=GradingScheme,
    fields=['scheme_name', 'grade', 'score_range_begin', 'score_range_end'],
    extra=10, max_num=100, can_delete=False
)

# Passing the pre-filled form for rendering. For the sake of illustration, I have hardcoded the `id=1`:
instance = GradingSchemeName.objects.get(id='1')        
context['grade_formset'] = GradeFormSet(instance=instance)

# checking the request data from the post(request) on form submission:
grades_formset = GradeFormSet(request.POST, instance=instance)

请注意，在创建表单集期间，

GradingScheme

模型中保存了3条记录。当我尝试使用上述方法更新时，我看到

grades\u formset

有13条记录（3条来自

实例属性，10条来自额外表单）。当执行
is\u valid（）
方法时，会导致该问题：

if not grades_formset.is_valid():
    messages.error(request, 'Form data is invalid!')

is\u valid（）
方法为3条记录中的每一条抛出以下错误：


id：此字段为必填字段
“errorlist非字段”：具有此方案名称和等级的评分方案已存在

不确定，如何修复上述两个错误。任何指示都会非常有用。提前感谢。
我喜欢基于类的视图，因此这将是我解决您问题的可能方法：

from django.db import transaction

class GradeUpdateView(UpdateView):
    template_name = 'Your Template'
    form_class = yourtemplateForm
    model = GradingSchemeName

    def get_context_data(self, **kwargs):
        context = super().get_context_data(**kwargs)

        if self.request.method == 'POST':
            context['formset'] = GradeFormSet(self.request.POST, instance=self.object)
        else:
            context['formset'] = GradeFormSet(instance=self.object)

        return context

    def form_valid(self, form):
        context = self.get_context_data()
        formset = context['formset']

        with transaction.atomic():
            self.object = form.save()

            if formset.is_valid():
                formset.instance = self.object
                formset.save()

        return redirect('your url')

我不知道如何使用form_类，我会检查一下。顺便说一句，我也在使用CBV，但是，视图代码太大，无法在StackOverflow中显示。下面是指向视图的完整实现的链接-。欢迎您的评论！为什么要在验证中使用scheme_name_id来知道它属于哪个方法？使用self.object就足以知道您要修改哪个对象。GradingSchemeNameForm进入form_类，这样它工作得更好，并且不需要选择类中的字段感谢您的反馈。我正在使用
scheme\u name\u id
确定要更新的
GradingScheme
。我的模板（）有两种形式。第一种形式设置了
方案\u名称\u id
，基于此选择，我将值填充到第二种形式中。第二种形式是
GradeFormSet
。