AttributeError at /coordinator‘协调人’object没有属性'agent‘

Question

预期结果:我想查询与协调程序相关的父对象。请帮助我如何实现这样的目标。

在运行以下查询集后出现错误，

user.coordinator.agent.parent_set.all()

模型

class Coordinator(models.Model):
user = OneToOneField(User, null=True, blank=True, on_delete=models.SET_NULL) 
region = models.CharField(max_length=15, null=True, blank=True, choices=REGION)
id_no = id_no = models.CharField(max_length=150, null=False, blank=False, unique=True)
address = models.TextField(null=False, blank=False)
gender = models.CharField(max_length=20, null=False, blank=False, choices=GENDER)
created_at = models.DateTimeField(auto_now_add=True)

class Agent(models.Model):
user = OneToOneField(User, null=True, blank=True, on_delete=models.SET_NULL)
coordinator = models.ForeignKey(Coordinator, null=True, blank=True, on_delete=SET_NULL)
region = models.CharField(max_length=15, null=True, blank=True, choices=REGION)
id_no = id_no = models.CharField(max_length=150, null=False, blank=False, unique=True,)
address = models.TextField(null=False, blank=False)
gender = models.CharField(max_length=20, null=False, blank=False, choices=GENDER)
created_at = models.DateTimeField(auto_now_add=True)

class Parent(models.Model):
   agent = models.ForeignKey(Agent, null=True, blank=True, on_delete=SET_NULL)
   surname = models.CharField(max_length=150, null=False, blank=False)
   first_name = models.CharField(max_length=150, null=False, blank=False)
   other_name = models.CharField(max_length=150, null=True, blank=True)
   address = models.CharField(max_length=200, null=True, blank=True)
   region = models.CharField(max_length=15, null=True, blank=True, choices=REGION)
   dob = models.CharField(max_length=10, null=False, blank=False)

Answer 1

您不能使用user.coordinator.agent.parent_set.all()，因为coordinator和agent之间没有直接关系。你应该这样做：

# Starting from a Coordinator
coordinator.user.agent.parent_set.all()
# Starting from a user
user.agent.parent_set.all()

注意，这可能会引发异常，因为您的OneToOneFields是可空的。

您必须更改您的模型以使您的查询工作如下：

class Agent(models.Model):
    coordinator = OneToOneField(Coordinator, null=True, blank=True, on_delete=models.SET_NULL)
    # Instead of 
    user = OneToOneField(User, null=True, blank=True, on_delete=models.SET_NULL)