python - 无法使用_set查询外键相关对象| Django ？

Question

无法访问外键相关对象，显示错误
我已经创建了 Hospital 和 Availablity 的实例，但是在使用 查询时H1.availablity_set.all()

 //error 
'Hospital' object has no attribute 'availablity_set'

模型.py

class Hospital(models.Model):
    name = models.CharField(max_length = 256)
    address = models.CharField(max_length=256,null=True, blank=True)
    phone = models.CharField(max_length=10)
    city = models.ForeignKey(City, on_delete=models.CASCADE, related_name = 'City')

    def __str__(self):
        return self.name

class Availablity(models.Model):
    hospital = models.ForeignKey(Hospital, on_delete = models.CASCADE, related_name='availablities')
    facility = models.ForeignKey(Facility, on_delete= models.CASCADE, related_name='facilities')
    updated_at = models.DateTimeField(auto_now=True)
    total = models.IntegerField(default=0)
    available = models.IntegerField(default=0)

代码

Answer 1

为您 hospital领域Availablity (秒)，您使用了 related_name='availablities' [Django-doc] ，这是反向关系的名称，因此您可以访问 Availability s 代表 Hospital :

my_hospital.availablities.all()

您的模型类和 related name s 有一些拼写错误。考虑重命名 Availablity至 Availability , related_name='availablities'至 related_name='availabilities' .此外，(通常)给出 related_name 没有多大意义。同名是 ForeignKey本身，因为这是您反向查询的方式。因此最好重命名 relaed_name到:

class Hospital(models.Model):
    # …
    city = models.ForeignKey(
        City,
        on_delete=models.CASCADE,
        related_name='city_hospitals'
    )