预存示例

Question

我以前从未使用过from django.db.models.signals import pre_save @receiver(pre_save, sender=Shows) def shows_receiver(sender, **kwargs): #if writer kwarg is null don't override current data class Poll(models.Model): director = models.CharField(max_length=128, blank=True, ) writer = models.CharField(max_length=128, blank=True, ) ，也没有找到任何好的例子。我想修改一个不应该为空的字段。如果给定字段已包含值，则不会发生任何事情。

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Answer 1

您可以通过修改传递给receiver的实例来实现它：

@receiver(pre_save, sender=Shows)
def shows_receiver(sender, instance, **kwargs):
    if instance.some_field == "":
        instance.some_field = "something"

或者对模型中的字段使用default值：

class Shows(models.Model):
    some_field = models.CharField(max_length=128, default="something")