Question

我遇到以下两个模型的问题。第一个模型（QueryJob）由第二个模型（PropertyQuery）引用多个到多个字段（queryID = models.ForeignKey（QueryJob，blank = True，null = True）），这需要QueryJob在PropertyQuery之前class QueryJob(models.Model): queryUID = models.AutoField(primary_key=True) client = models.ManyToManyField(Client,blank=True) Json = JSONField() street_column =models.TextField() state_column =models.TextField(blank=True) suburb_column =models.TextField(blank=True) postcode_column =models.TextField(blank=True) def createqueries(self): #json_data = json.loads(self.Json) print self.Json for each in self.Json: try: Street = each[self.street_column] State = each[self.state_column] Suburb = each[self.suburb_column] Postcode = each[self.postcode_column] q = PropertyQuery(street_address = Street, state=State ,suburb = Suburb,postcode=Postcode,queryID=self.queryUID ) q.save() except: pass def save(self, *args, **kwargs): self.createqueries() super(QueryJob, self).save(*args, **kwargs) 1}}。

如何通过调用QueryJob.createqueries（）来创建PropertyQuery对象，这需要PropertyQuery在QueryJob之前。

代码如下。有没有更好的方法来解决这个问题？

class PropertyQuery(models.Model):
  queryID = models.ForeignKey(QueryJob,blank=True,null=True)
  linkedproperty = models.ForeignKey(Property,blank=True,null=True)
  street_address = models.CharField(max_length=255, db_index=True,null=True)
  suburb = models.CharField(max_length=120, db_index=True,blank=True,null=True)
  state = models.CharField(max_length=3, db_index=True,blank=True,null=True)
  postcode = models.IntegerField(max_length=4, db_index=True, blank=True,null=True)
  matcheduncertainty = models.PositiveSmallIntegerField(blank=True,null=True)
  def search_for_a_match(self):
    if self.postcode:
      print self.postcode

      print Property.objects.filter(postcode=self.postcode)
      try:
        property_list = Property.objects.filter(postcode=self.postcode)

        print property_list 
      except:
        print "no properties in that postcode"
        return
    elif self.suburb:
      try:
        property_list = Property.objects.filter(suburb=self.suburb)
        print property_list 
      except:
        print "no properties in that suburb"
    elif self.state:
      try:
        property_list = Property.objects.filter(state=self.state)
        print property_list 
      except:
        print "no properties in that state"
        return
    else:
      print "no properties found"
      return
    for possible in property_list:
      if possible.street_address == self.street_address:
        self.linkedproperty = possible
        self.matcheduncertainty = 100
        return
    else:
      print "we will need to try something else"

第二个模型

{{1}}

Answer 1

切换这些语句的顺序，以便首先创建QueryJob，然后创建PropertyQuery模型：

def save(self, *args, **kwargs):
    super(QueryJob, self).save(*args, **kwargs)
    self.createqueries()

在createqueries()方法中，您可以在需要创建链接时参考self。不要直接创建主键的链接，因为这不起作用 - 你没有意识到它不起作用，因为你有一个空白的except子句来捕捉引发的异常：

def createqueries(self):
    #json_data = json.loads(self.Json)
    print self.Json
    for each in self.Json:
        Street = each.get(self.street_column)
        State = each.get(self.state_column)
        Suburb = each.get(self.suburb_column)
        Postcode = each.get(self.postcode_column)
        q = PropertyQuery(street_address = Street,
                          state=State,
                          suburb = Suburb,
                          postcode=Postcode,
                          queryID=self)
        q.save()

Django模型具有多对多关系，导致models.py中的订购要求相互矛盾

1 个答案: