在Django设计通知系统的适当模式?

我正试图在Django创建一个通知系统。通知类型字段、用户ID和不同表(如注释、关系表)的外键是否更好?

或者,除了所有通知都有一个用户ID字段之外,它们还应该为每种通知类型都有一个单独的表,如“相似通知”、“注释通知”等?

设计1:

class LikeNotification(models.Model):
    post = models.ForeignKey(Post, on_delete=models.CASCADE)
    user = models.ForeignKey(User, on_delete=models.CASCADE)

class CommentNotification(models.Model):
    post = models.ForeignKey(Post, on_delete=models.CASCADE)
    user = models.ForeignKey(User, on_delete=models.CASCADE)

class PostNotification(models.Model):
    post = models.ForeignKey(Post, on_delete=models.CASCADE)
    user = models.ForeignKey(User, on_delete=models.CASCADE)


class BondNotification(models.Model):
    bond = models.ForeignKey(Bond, on_delete=models.CASCADE,)
    user = models.ForeignKey(User, on_delete=models.CASCADE)

设计2:

class Notification(models.Model):
    notification_type = models.IntegerField()
    user = models.ForeignKey(User, on_delete=models.CASCADE)
    like = models.ForeignKey(Like, on_delete=models.CASCADE)
    comment = models.ForeignKey(Comment, on_delete=models.CASCADE)
    bond = models.ForeignKey(Bond, on_delete=models.CASCADE)
    post = models.ForeignKey(Post, on_delete=models.CASCADE)