from django.db import models # Create your models here. class Author(models.Model): name = models.CharField(max_length=32) class Book(models.Model): name = models.CharField(max_length=32) author = models.ForeignKey(to=Author, on_delete=models.CASCADE, null=False) remark = models.CharField(max_length=32, null=True) def print_name(self): print(self.name) @classmethod def print_class_name(cls): print(cls.__name__)