我如何在 django 中比较两个模型字段？

发布于 2024-10-19 01:18:01 字数 305 浏览 1 评论 0原文

我的 Models.py 文件中有这个模型。我想比较“start_date”和“end_date”，以便 start_date 值永远不会大于 end_date，反之亦然。我如何进行此验证？

class Completion(models.Model):

    start_date = models.DateField()
    end_date = models.DateField()
    batch = models.ForeignKey(Batch)
    topic = models.ForeignKey(Topic)

原文

I have this Model in my Models.py file.I want to to compare "start_date" and "end_date" so that start_date value would never be greater then end_date or vice-versa.How do i do this validation?

class Completion(models.Model):

    start_date = models.DateField()
    end_date = models.DateField()
    batch = models.ForeignKey(Batch)
    topic = models.ForeignKey(Topic)

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邮友 2024-10-26 01:18:01

我将开始让您了解模型验证框架。
http:https://docs .djangoproject.com/en/2.0/ref/models/instances/#django.db.models.Model.clean

它由 ModelForms 使用，并且开始很有意义使用它。

基本上，您可以在模型中定义一个 clean() 方法，放入验证逻辑，并在失败时引发 ValidationError 。

class MyModel(models.Model):
    def clean(self):
        from django.core.exceptions import ValidationError
        if self.start_data > self.end_date:
            raise ValidationError('Start date cannot precede end date')


    def save(self, *args, **kwargs):
        # you can have regular model instance saves use this as well
        super(MyModel, self).save(*args, **kwargs)

这里的好处是任何ModelForm（这意味着管理站点也会调用full_clean()，这反过来会调用您的模型clean() 无需任何额外工作。

无需覆盖 save_model，您将在管理表单顶部看到常见的验证错误。
description

最后，它非常方便。您可以在任何地方使用它。

try:
    my_model.full_clean()
except ValidationError, e:
    # Do something based on the errors contained in e.message_dict.
    # Display them to a user, or handle them programatically.

I'd start getting your head into the Model Validation framework.
http:https://docs.djangoproject.com/en/2.0/ref/models/instances/#django.db.models.Model.clean

It's used by ModelForms and just makes a whole lot of sense to start using it.

Basically, you'd define a clean() method in your model, put in your validation logic, and raise ValidationError if it fails.

class MyModel(models.Model):
    def clean(self):
        from django.core.exceptions import ValidationError
        if self.start_data > self.end_date:
            raise ValidationError('Start date cannot precede end date')


    def save(self, *args, **kwargs):
        # you can have regular model instance saves use this as well
        super(MyModel, self).save(*args, **kwargs)

The benefit here is that any ModelForm (which means the admin site too will call full_clean(), which in turn calls your model clean() without any extra work.

No need to override save_model, you'll get the usual validation errors at the top of the admin form.
description

Finally, it's super convenient. You can use it anywhere.

try:
    my_model.full_clean()
except ValidationError, e:
    # Do something based on the errors contained in e.message_dict.
    # Display them to a user, or handle them programatically.

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