Django：从两个模型字段过滤Queryset [英] Django: Filtering Queryset From Two Model Fields

问题描述

我的模型有两个字段（经度和纬度），我想合并成一个点对象。然而，我不知道如何基于这些值的组合进行过滤：

例如：

 >>> from django.contrib.gis.geos import Point 
>>> lat = 5 
>>> lon = 1 
>>> pnt = Point（lat，lon）
>>> buf = pnt.buffer（0.0001）
>>> z = Thing.objects.filter（pnt__intersects = buf）
 
 FieldError：无法将关键字pnt解析为字段。 ##我没有一个名为pnt的模型字段
  

我意识到这不是正确的方法，但是我认为它说明了我有的问题。如何将两个模型字段（ lat + lon ）合并为一个 Point 对象，然后基于该点过滤？ / p>

---

编辑：添加事物模型

  class Thing（models.Model）：
 lat = models.FloatField（）
 lon = models.FloatField（）
  

解决方案

最简单的方法就是@karthikr在你的问题的评论中说过， p>

  z = Thing.objects.filter（lat = pnt.get_x（），lng = pnt.get_y（））
  

另外，我不知道数据库有多少回旋余地，但是也可以分别存储点你的Thing对象，然后把Thing对象连接到一个Point？

psuedocode：

 类Thing（models.Model）：
 point = models.ForeignKey（'Point'）
 
 class Point（models.Model）：
 lat = models.FloatField（）
 lon = models.FloatField（ ）
 
 
z = Thing.objects.filter（point = Point.objects.get（lat，long））
  

否则，我不认为有办法做你所要求的。

My model has two fields (latitude and longitude) that I want to combine to form a point object. However, I cannot figure out how to filter based on a combination of those values:

For example:

>>> from django.contrib.gis.geos import Point
>>> lat = 5
>>> lon = 1
>>> pnt = Point(lat, lon)
>>> buf = pnt.buffer(0.0001)
>>> z = Thing.objects.filter(pnt__intersects=buf) 

FieldError: Cannot resolve keyword 'pnt' into field.   ## I dont have a model field named pnt

I realize this is not the right approach, but I think it illustrates the problem that I am having. How can I combine two model fields — lat + lon — into a Point object then filter based on that point?

---

EDIT: adding thing model

class Thing(models.Model):
    lat = models.FloatField()
    lon = models.FloatField()

解决方案

The most straightforward way to do this is as @karthikr has said in the comments to your question, just AND the two:

z = Thing.objects.filter(lat=pnt.get_x(), lng = pnt.get_y())

Alternatively, I don't know how much leeway you have in the database, but you could also store the points separately from your Thing object, and then just link the Thing object to a Point?

psuedocode:

class Thing(models.Model):
   point = models.ForeignKey('Point')

class Point(models.Model):
   lat = models.FloatField()
   lon = models.FloatField()


z = Thing.objects.filter(point = Point.objects.get(lat, long))

Otherwise, I don't think there's a way to do what you're asking.

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