django使用q对象动态过滤 [英] django dynamically filtering with q objects

问题描述

我试图根据用户输入标签查询数据库。标签的数量可以是0-5，所以我需要动态创建查询。

所以我有一个标签列表，tag_list，我想查询数据库：

  design_list = Design.objects.filter（Q（tags__tag__contains =tag1）和Q（tags__tag__contains =tag2 ）等等）
  

如何创建此功能？

解决方案

你需要循环使用tag_list并为每个应用一个过滤器。

  tag_list = ['tag1'，'tag2'，'tag3'] 
 base_qs = Design.objects.all（）
 for t in tag_list：
 base_qs = base_qs.filter（tags__tag__contains = t）
  

这将为您提供与 / em>标签，您的示例以和表示。如果事实上你需要或，你可能需要Q对象。

编辑： strong>我想我现在有你想要的东西。

  tags = ['tag1'，'tag2'，' tag3'] 
 q_objects = Q（）＃在标签中创建一个空的Q对象，以
开头：
 q_objects | = Q（tags__tag__contains = t）＃'或'Q对象一起
 
 designs = Design.objects.filter（q_objects）
  

我测试

编辑2：在Freenode的#django中感谢kezabelle的初步想法。 >

I'm trying to query a database based on user input tags. The number of tags can be from 0-5, so I need to create the query dynamically.

So I have a tag list, tag_list, and I want to query the database:

design_list = Design.objects.filter(Q(tags__tag__contains = "tag1") and Q(tags__tag__contains = "tag2") and etc. etc. )

How can I create this feature?

解决方案

You'll want to loop through the tag_list and apply a filter for each one.

tag_list = ['tag1', 'tag2', 'tag3']
base_qs = Design.objects.all()
for t in tag_list:
    base_qs = base_qs.filter(tags__tag__contains=t)

This will give you results matching all tags, as your example indicated with and. If in fact you needed or instead, you will probably need Q objects.

Edit: I think I have what you're looking for now.

tags = ['tag1', 'tag2', 'tag3']
q_objects = Q() # Create an empty Q object to start with
for t in tags:
    q_objects |= Q(tags__tag__contains=t) # 'or' the Q objects together

designs = Design.objects.filter(q_objects)

I tested this and it seems to work really well.

Edit 2: Credit to kezabelle in #django on Freenode for the initial idea.

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