Django2 外鍵遇到的坑

# 出版社
class Publisher(models.Model): # 自增、主鍵 id
    id = models.AutoField(primary_key=True) # varchar(32)、不爲空、惟一索引
    name = models.CharField(max_length=32, null=False, unique=True) # 書
class Booker(models.Model): id = models.AutoField(primary_key=True) title = models.CharField(max_length=64, null=False, unique=True) publisher = models.ForeignKey(to="Publisher")

報錯

解決方案

publisher = models.ForeignKey(to="Publisher", on_delete=models.CASCADE)

 問題

解決

publisher = models.ForeignKey(to="Publisher", on_delete=models.CASCADE, default=1)