Django模型中的字段分配

Question

I add a method to PictureBook model,

class PictureBook(models.Model):
    license = models.CharField(max_length=200, unique=True)
    activate_count = models.IntegerField(default=0)

    # check if the license is available.
    def activate(self, license=None):
        if self.activate_count != 2 and self.license == license:
            import pdb; pdb.set_trace()
            self.activate_count += 1
            return True
        else:
            return False

then call activate() in views.py , I have added

import pdb; pdb.set_trace()

then I see output,

-> self.activate_count += 1
(Pdb) 

I type 'c', program continue. And I check the value activate_count in admin, it should be 1, but it still 0. Thanks in advance.

Answer 1

您没有保存模型实例。

Answer 2

You have to add self.save() after you increase it, so that it actually saves your changes:

def activate(self, license=None):
        if self.activate_count != 2 and self.license == license:
            import pdb; pdb.set_trace()
            self.activate_count += 1
            self.save()
            return True
        else:
            return False