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[英]Accessing the data of a Parent model from a sub Model using the foreign key in Django
[英]How to display data from parent model using foreign key django
我想在查询集中显示子 model 数据和父 model 数据。
这是我在 model.py 中的模型
class Shareholders(models.Model):
sharehold_IC = models.CharField(primary_key=True, unique=True, validators=[RegexValidator(r'^\d{12,12}$'), only_int], max_length=12)
sharehold_name = models.CharField(max_length=100, null=True)
sharehold_email = models.CharField(max_length=50, null=True, unique=True)
sharehold_address = models.TextField(null=True, blank=True)
password = models.CharField(max_length=100)
def __str__(self):
return self.sharehold_name
class Meeting(models.Model):
MEETING_STATUS = (
('Coming Soon', 'Coming Soon'),
('Live', 'Live'),
('Closed', 'Closed')
)
meeting_ID = models.CharField(primary_key=True, max_length=6, validators=[RegexValidator(r'^\d{6,6}$')])
meeting_title = models.CharField(max_length=400, null=True)
meeting_date = models.DateField()
meeting_time = models.TimeField()
meeting_desc = models.CharField(max_length=500, null=True)
meeting_status = models.CharField(max_length=200, null=True, choices=MEETING_STATUS)
date_created = models.DateTimeField(default=timezone.now, null=True)
def __str__(self):
return self.meeting_ID
class Question(models.Model):
question_ID = models.AutoField(primary_key=True)
question = models.CharField(max_length=400, null=True)
meeting_id = models.ForeignKey(Meeting, on_delete=CASCADE)
shareholder_IC = models.ForeignKey(Shareholders_Meeting, on_delete=CASCADE, related_name='shareholder_ic')
date_created = models.DateTimeField(default=timezone.now, null=True)
def __str__(self):
return str(self.meeting_id)
我尝试显示问题model 中的所有数据以及股东详细信息,例如股东model 的sharehold_name 。这就是我在Views.py中尝试做的事情。
视图.py
def getMessages(response, meeting_id):
meeting = Meeting.objects.get(meeting_ID=meeting_id)
questions = Question.objects.filter(meeting_id=meeting.meeting_ID)
# print(list(questions.values('shareholder_IC_id')))
for i in questions:
print(i.shareholder_ic.all())
return JsonResponse({"questions":list(questions.values())})
但不知何故我得到了这个错误AttributeError: 'Question' object has no attribute 'shareholder_ic'
。 我想得到这样的结果:
{'question_ID': 141, 'question': "I'm good. How are you?", 'meeting_id_id': '731404', 'shareholder_IC_id': '122311221231', 'date_created': datetime.datetime(2021, 10, 7, 3, 40, 12, 160029, tzinfo=<UTC>), 'sharehold_name':'John Steve', 'sharehold_email':'john@gmail.com'}
我该如何解决这个问题,或者有其他方法可以显示数据吗? 提前致谢
您必须使用向后关系
questions = Question.shareholder_ic.filter(meeting_id=meeting.meeting_ID)
不要在object上碰它
对于其他设置,在管理器中创建所需的查询集
首先,您没有正确使用Question
related_name
中的 related_name 属性。 这不是使用替代名称来指代相关的 model,相反,它是您要用来指代来自相关 model 的Question
model 的名称,在您的案例中是Shareholders
。 你必须重新制作你的 model:
class Question(models.Model):
question_ID = models.AutoField(primary_key=True)
question = models.CharField(max_length=400, null=True)
meeting_id = models.ForeignKey(Meeting, on_delete=CASCADE)
shareholder_IC = models.ForeignKey(Shareholders_Meeting, on_delete=CASCADE, related_name='questions')
date_created = models.DateTimeField(default=timezone.now, null=True)
def __str__(self):
return str(self.meeting_id)
然后,在您的views.py
中,您需要在Question
model 中使用正确的属性名称,即shareholders_IC
:
def getMessages(request, meeting_id): # <- Shouldn't the first param be request?
meeting = Meeting.objects.get(meeting_ID=meeting_id)
# No need to use meeting.meeting_ID here, you can use the meeting instance
questions = Question.objects.filter(meeting_id=meeting)
for i in questions:
print(i.shareholder_IC) # <- No .all(), a question has only one shareholder
return JsonResponse({"questions":list(questions.values())})
但是,要实现您想要的效果,您应该使用 Django REST Framework,或者自己序列化您将获得的不同实例:
def getMessages(request, meeting_id):
meeting = Meeting.objects.get(meeting_ID=meeting_id)
questions = Question.objects.filter(meeting_id=meeting)
questions_list = []
for i in questions:
questions_list.append(
{
"question_ID": i.question_ID,
"question": i.question,
"shareholder_IC_id": i.shareholder_IC.shareholder_IC,
...
}
)
return JsonResponse(questions_list)
我会推荐两个主要的东西:
Question
中有属性meeting_id
。 虽然在内部确实使用 id 来查询Meeting
,但该属性与 model 有关系,而不是 ID。
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