Question

我正在尝试检查并在添加条目之前查看数据库中是否存在重复条目。以下是我目前的型号 -

class Education(models.Model):
    school = models.CharField(max_length=100)
    class_year = models.IntegerField(max_length=4, blank=True, null=True, choices=YEAR)
    degree = models.CharField(max_length=100, blank=True, null=True)

class UserProfile(models.Model):
    user = models.ForeignKey(User, unique=True)
    employments = models.ManyToManyField(Employment)

在表单上，用户必须进入学校。课程年级和学位是可选的。要检查重复的条目，现在我有 -

if form.is_valid() and request.POST['school']:
    school = form.cleaned_data['school']
    try:
        school_object = Education.objects.get(school=form.cleaned_data['school'],
                                              class_year=form.cleaned_data['class_year'],
                                              degree = form.cleaned_data['degree'])
    except (Education.DoesNotExist):
        school_object = Education(school=form.cleaned_data['school'],
                                  class_year=form.cleaned_data['class_year'],
                                  degree = form.cleaned_data['degree'])
        school_object.save()
        profile.educations.add(school_object)
        profile.save()

如果没有填写class_date，我会收到ValueError。如何修复此问题以及检查重复项时？谢谢。

Answer 1

首先，除非你有充分的理由，否则你真的不应该访问帖子变量而不通过表格发送它们。

from django import forms
class MyForm(forms.form):
  school = forms.CharField()
  degree = forms.CharField(required=False)
  class_year = forms.CharField(required=False)

  def clean(self):
    if not self.cleaned_data.has_key('degree'):
      self.cleaned_data['degree'] = None
    if not self.cleaned_data.has_key('class_year'):
      self.cleaned_data['class_year'] = None
    return self.cleaned_data

然后当你处理视图时：

...
if request.method == "POST":
  form = MyForm(request.POST)
  if form.is_valid():
    try:
      # NOTE that the objects.get method will raise MultipleObjectsReturned if the
      # database has more than one object that matches the query
      my_object = Education.objects.get(school=form.cleaned_data['school'], 
        class_year=form.cleaned_data['class_year'], 
        degree = form.cleaned_data['degree'])
    except Education.DoesNotExist:
      my_object = Education(school=form.cleaned_data['school'], 
        class_year=form.cleaned_data['class_year'], 
        degree = form.cleaned_data['degree'])
else:
  form = MyForm()
...

Answer 2

观点：

if 'Add School' in request.POST.values():
    form = EducationForm(request.POST)
    if form.is_valid() and request.POST['school']:
        school = form.cleaned_data['school']
        try:
            school_object = Education.objects.get(school=form.cleaned_data['school'],
                                              class_year=form.cleaned_data['class_year'],
                                              degree = form.cleaned_data['degree'])
        except (Education.DoesNotExist, ValueError):
            school_object = Education(school=form.cleaned_data['school'],
                                              class_year=form.cleaned_data['class_year'],
                                              degree = form.cleaned_data['degree'])
            school_object.save()
            profile.educations.add(school_object)
            profile.save()
            return redirect('edit_education')

或者，使用get_or_create来简化：

if 'Add School' in request.POST.values():
    form = EducationForm(request.POST)
    if form.is_valid() and request.POST['school']:
        school = form.cleaned_data['school']
        school_object, created = Education.objects.get_or_create(school=form.cleaned_data['school'],
                                          class_year=form.cleaned_data['class_year'],
                                          degree = form.cleaned_data['degree'])
        if created:
            profile.educations.add(school_object)
            profile.save()
            return redirect('edit_education')

表格：

YEAR = ([(x, x) for x in range(1970,2015)])
YEAR.append((0,'Select Year'))
YEAR.reverse()

class EducationForm(forms.Form):
    school = forms.CharField()
    class_year = forms.ChoiceField(choices=YEAR, required=False)
    degree = forms.CharField(required=False)
    def clean(self):
        if not self.cleaned_data.get('class_year'):
            self.cleaned_data['class_year'] = None
        if not self.cleaned_data.get('degree'):
            self.cleaned_data['degree'] = ''
        return self.cleaned_data

检查数据库是否与Null字段重复

2 个答案: