如何进行多级查询?我的模特是
from django.db import models
class Subjects(models.Model):
name=models.CharField(max_length=20)
pub_date= models.DateTimeField(auto_now=True)
def __str__(self):
return self.name
class Question(models.Model):
subject = models.ForeignKey(Subjects)
ques = models.CharField(max_length=100)
pub_date=models.DateTimeField(auto_now=True)
def __str__(self):
return self.ques
class Answer(models.Model):
question = models.ForeignKey(Question)
ans1 = models.CharField(max_length=50)
ans2 = models.CharField(max_length=50)
ans3 = models.CharField(max_length=50)
def __str__(self):
return self.ans1
我想从主题2的问题23中查询,并回答问题2。以相反的顺序,我想查询Answer.objects.get(pk = 2),这是Question.objects.get(pk = 23)的答案,而这个问题来自Subjects.objects.get(pk = 2)。我怎样才能做到这一点?
就像这样
s = Subjects.objects.get(name="No.2")
q = Question.objects.get(subject=s, ques="no.23")
a = Answer.objects.get(question=q, ans2="some answer?")
本文收集自互联网,转载请注明来源。
如有侵权,请联系[email protected] 删除。
我来说两句