一旦设置为 null，如何在 Django model 中使用默认值？

Question

I have this model in my django app:

class Person(models.Model):
    name = models.CharField(max_length=50)
    image = models.ImageField(blank=True, upload_to='images', default='default/static/image/here')

    def __str__(self):
        return self.name

When making a Person object, if left empty, the "image" is set to a default value, but later, if the user decides to remove his image, his image will no longer be set to default but to NULL instead. How can I make it so that whenever image is NULL again, it automatically brings back the default value?

Answer 1

When image will be changed, ImageField won't be Null. You can just set default image. if user want to remove his image, default image again will appear.

Answer 2

You can modify the save method that checks if the ImageField is Null

class Person(models.Model):
    name = models.CharField(max_length=50)
    image = models.ImageField(blank=True, upload_to='images', default='default/static/image/here')

    def __str__(self):
        return self.name

    def save(self, *args, **kwargs):
        if not self.image:  #here
            self.image = 'default/static/image/here'
        super(Person, self).save(*args, **kwargs)