在django中扩展基础模型

lnlaulya  于 2023-03-20  发布在  Go
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我想创建名为Question的问题的基础模型,并通过任何其他问题类型扩展它:

class Question(models.Model):
    questionnaire = models.ForeignKey(to='Questionnaire', on_delete=models.CASCADE, related_name='questions')
    question = models.TextField()
    description = models.TextField(null=True, blank=True)
    media = models.FileField(upload_to='medias', blank=True, null=True)
    is_required = models.BooleanField(default=False)

    def __str__(self):
        return f'{self.questionnaire.name} - {self.question}'

我想这样扩展它

class OptionalQuestion(Question):
    multiple_choice = models.BooleanField(default=False)
    additional_options = models.BooleanField(default=False)
    # If multiple_choice is True, then max_selected_options and min_selected_options will be used
    max_selected_options = models.IntegerField(null=True, blank=True)
    min_selected_options = models.IntegerField(null=True, blank=True)

    # If additional_options is True, then all_options and nothing_selected will be used
    all_options = models.BooleanField(default=False, null=True, blank=True)
    nothing_selected = models.BooleanField(default=False, null=True, blank=True)

    def save(self, *args, **kwargs):
        if not self.multiple_choice:
            self.max_selected_options = None
            self.min_selected_options = None
        if not self.additional_options:
            self.all_options = None
            self.nothing_selected = None
        if self.nothing_selected or self.all_options:
            self.all_options = False
            self.multiple_choice = False
        super().save(*args, **kwargs)

这在第一次创建迁移时是很好的,但是下一次Django要我为'question_ptr'字段提供默认值时,我甚至不知道这个字段是什么
我试着让基类抽象化,但在迁移时Django显示了很多错误,比如:

question_app.TextAnswerQuestion.questionnaire: (fields.E305) Reverse query name for 'question_app.TextAnswerQuestion.questionnaire' clashes with reverse query name for 'question_app.DropDownQuestion.questionnaire'.
        HINT: Add or change a related_name argument to the definition for 'question_app.TextAnswerQuestion.questionnaire' or 'question_app.DropDownQuestion.questionnaire'.
question_app.TextAnswerQuestion.questionnaire: (fields.E305) Reverse query name for 'question_app.TextAnswerQuestion.questionnaire' clashes with reverse query name for 'question_app.NumberAnswerQuestion.questionnaire'.
        HINT: Add or change a related_name argument to the definition for 'question_app.TextAnswerQuestion.questionnaire' or 'question_app.NumberAnswerQuestion.questionnaire'.
question_app.TextAnswerQuestion.questionnaire: (fields.E305) Reverse query name for 'question_app.TextAnswerQuestion.questionnaire' clashes with reverse query name for 'question_app.OptionalQuestion.questionnaire'.
        HINT: Add or change a related_name argument to the definition for 'question_app.TextAnswerQuestion.questionnaire' or 'question_app.OptionalQuestion.questionnaire'.

我不知道该怎么办

7uzetpgm

7uzetpgm1#

首先,使问题模型抽象= True
当抽象基类中具有ForeignKey关系时,每个派生类都将具有此关系。因此,不能硬编码related_name,因为所有派生类都将尝试在相关类上创建相同的访问器。
正如Django文档所建议的,你可以在Questionmodel中做一些类似的事情:

questionnaire = models.ForeignKey(to='Questionnaire', on_delete=models.CASCADE, related_name="%(app_label)s_%(class)s_questions")

查看Django文档点击这里

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