如何检查 Django 表单中的唯一数据？

Question

我正在关注Django Formset Documents 上发布的关于自定义表单集验证的示例，并稍作修改。我在示例中发现了一个缺陷，但不确定如何修复它。如果 3 个输入字段中的 1 个未完全填写，有没有办法检查数据的唯一性？显然，空表格被记录为“无”，这迫使我至少填写 2/3 组输入字段（名字/姓氏）；否则，它将注册为重复项。为了说明我的意思：

forms.py

class UserInfo (forms.Form):

    first_name = forms.CharField (max_length = 20, required = False)
    last_name = forms.CharField (max_length = 20, required = False)


class BaseUserInfoFormSet (BaseFormSet):

    def clean (self):
        if any (self.errors):
            return

        firstnames = []
        lastnames = []
        errors = []

        for form in self.forms:
            firstname = form.cleaned_data.get ('first_name')
            lastname = form.cleaned_data.get ('last_name')

            if ((firstname in firstnames) or (lastname in lastnames)) and len (errors) < 2:
                errors.append ('First and/or last name must be unique')
            if ((firstname == '') or (lastname == '')) and len (errors) < 2:
                errors.append ('First and/or last name cannot be blanked')

            firstnames.append (firstname)
            lastnames.append (lastname)
            print ('First Name List: ', firstnames)
            print ('Last Name List: ', lastnames)

        if errors:
            raise forms.ValidationError (errors)

        return self.cleaned_data

只填写了一组名字/姓氏，这是控制台的结果。

First Name List:  ['John']
Last Name List:  ['Doe']

First Name List:  ['John', None]
Last Name List:  ['Doe', None]

First Name List:  ['John', None, None]
Last Name List:  ['Doe', None, None]

因为有重复的“None”，所以触发了错误：

errors.append ('First and/or last name must be unique')

Answer 1

我想我通过添加一个“if”语句来检查无。

if (firstname or lastname) is not None:
    firstnames.append (firstname)
    lastnames.append (lastname)

Answer 2

澄清一下，您不需要空白值，所以为什么不将这些字段设为必填项。这将完全消除 None 问题，因为所有字段都是必需的。

否则，您只能将不为空的值添加到列表中

if firstname: 
    firstnames.append(firstname)
if lastname: 
    lastnames.append(lastname)