Django联盟查询 [英] Django Union Query

问题描述

我需要在Django中开发一个UNION查询，其中有3个模型，即WebQuery，WebReply和BusinessOwners，输出应该是下面的形式。

 code $ {
（#conversation_id＃）_（＃b_id＃）：{
from：（#user_id），
email ＃
date_time：＃从db，
查询：你是否打开？，
from_r_id：（#representative_id） 
from_r_name：（#rep_name），
business_registered：FALSE
to_business_name：CCD saket，
chat：[{
direction：1，
text：yes sir，
date_time：424 577
}，{
direction：0 ，
text：ok，
date_time：424 577
}] 
}，
  pre> 
 
 
我知道如何查询当只涉及一个模型，但不能确定联合查询。 
这将如何实现？
解决方案
我个人会说，如果这将是一个常见的查询我建议做一个SQL View然后查询。
 
 
 
 w3schools对一个视图有一个非常简单的概述： http://www.w3schools.com/sql/sql_view.asp  
 
 
在SQL中，视图是基于SQL语句结果集的虚拟表。
 
 
这意味着您可以编写所需的sql语句并使用此命令创建视图。然后创建一个镜像该视图的django模型，然后您可以使用它查询。
 
 
 
所以，您将创建一个SQL视图：
  CREATE VIEW view_name AS 
 SELECT a，b，c 
 FROM table_name 
 WHERE条件
  
然后创建一个django模型，与一个正常的模型略有不同：
  class view_name（models.Model）：
 class Meta：
＃https://docs.djangoproject.com/en/1.5/ref/models/options/ ＃django.db.models.Options.managed 
 managed = False 
 
a = models.CharField（max_length）
 .... 
  
   managed = false >  https://docs.djangoproject.com/en/1.5/ref/models/选项/＃django.db.models.Options.managed   
 
 
 
然后，您可以使用规范来查询或者还有类似的问题：
 
 
 
 上一个stackoverflow问题，django orm中的union  
 
 
 
 我可以找到两个Django查询的联合吗？ 
 
I need to develop a UNION query in Django with 3 models namely WebQuery,WebReply and BusinessOwners and the output should be of the form below.
{
    "(#conversation_id#)_(#b_id#)": {
        "from": "(#user_id)",
        "email": "(#user_email)",
        "date_time": "#get from db",
        "query": "are you open ?",
        "from_r_id": "(#representative_id)",
        "from_r_name": "(#rep_name)",
        "business_registered": "FALSE"
        "to_business_name": "CCD saket",
        "chat": [{
            "direction": 1,
            "text": "yes sir",
            "date_time": "424 577"
        }, {
            "direction": 0,
            "text": "ok",
            "date_time": "424 577"
        }]
    },
I know how to query when only one model is involved, but not sure of the union query.
How will this be achieved?
解决方案
I personally would say that if this is going to be a common query then I would recommend making a SQL View then querying that.

w3schools has a VERY simple overview of what a view is : http://www.w3schools.com/sql/sql_view.asp

  
In SQL, a view is a virtual table based on the result-set of an SQL statement.
This means you can write your required sql statement and create a view using this. Then create a django model which mirrors that view which you can then use to query.

So, you will create an SQL view:
CREATE VIEW view_name AS
    SELECT a, b, c
    FROM table_name
    WHERE condition
Then create a django model, which has a slight difference to a normal model:
class view_name(models.Model):
    class Meta:
        # https://docs.djangoproject.com/en/1.5/ref/models/options/#django.db.models.Options.managed
        managed = False

    a = models.CharField(max_length)
    ....
managed = false > https://docs.djangoproject.com/en/1.5/ref/models/options/#django.db.models.Options.managed

You can then query this using the normal django orm syntax

Or there is similar questions:

Previous stackoverflow question, union in django orm

How can I find the union of two Django querysets?

                        
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