[英]django how to group on ManyToMany relationship dynamically
I have what I believe is a simple request but I have been beating my head against a wall and I am not getting any smarter for it. 我有一个简单的请求,但是我一直在碰壁,但我并没有因此而变得更聪明。
I am using django 1.10. 我正在使用Django 1.10。 What I am trying to do is get a list of my members grouped by my family field 我要做的是获取按家庭领域分组的成员列表
The models look like this: 这些模型如下所示:
class Family(models.Model):
family_name = models.CharField(max_length=200)
class Member(models.Model):
name = models.OneToOneField(User)
family = models.ManyToManyField(Family,blank=True,related_name='members')
So i can set my view to use 所以我可以设置我的观点来使用
members = Member.objects.order_by('family')
or 要么
members = Family.objects.order_by('family_name')
This obviously holds my members or my families but not both. 这显然可以容纳我的成员或家人,但不能同时容纳这两个成员。 How would i get this to have both the member name and their family and then group by it? 我将如何获得会员名称和他们的家人,然后按它分组?
An Example of the output i am looking for is: 我正在寻找的输出示例是:
Family 1 家庭1
Family 2 家庭2
Any help would be appreciated. 任何帮助,将不胜感激。
What's wrong with the first one? 第一个怎么了? If you want to order it by the family's name
, do: 如果要按家人的name
订购,请执行以下操作:
members = Member.objects.order_by('family__family_name')
These members all have their family available via .family
. 这些成员都可以通过.family
获得.family
。 If you want to save db queries when you are looping through these members and access their families, you can add a select_related
: 如果要在遍历这些成员并访问它们的族时保存数据库查询,则可以添加select_related
:
members = Member.objects.order_by('family__family_name').select_related('family')
On the other hand, if you really want families and then loop through their members, do: 另一方面,如果您真的想要家庭,然后与他们的成员进行交流,请执行以下操作:
families = Family.objects.order_by('family_name').prefetch_related('members')
for fam in families:
// do sth. with family
for mem in fam.members.all():
// do sth. with member
The prefetch_related will make this run with only 2 db queries, no matter how many families or members. 无论有多少族或成员, prefetch_related都将仅使用2个数据库查询来运行该查询。
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