如何向具有多对一关系的模型的 Django 管理员添加可排序的计数列? [英] How to add a sortable count column to the Django admin of a model with a many-to-one relation?

问题描述

假设我有一个 Book 模型，其中包含一个 Publisher 模型的外键.

Suppose I have a Book model containing a foreign key to a Publisher model.

如何在 Django 管理中显示每个出版商出版的书籍数量的列，以我可以使用内置排序的方式?

How can I display in the Django admin a column with the number of books published by each publisher, in a way that I can use the built-in sorting?

推荐答案

我遇到了同样的问题(我无法更改模型的管理器以添加慢速注释或连接).这里的两个答案的组合有效.@Andre 非常接近，Django Admin 支持仅为管理员修改查询集，因此在此处应用相同的逻辑，然后使用 admin_order_field 属性.当然，您仍然需要将新的管理字段添加到 list_display.

I had the same issue (I cannot change my model's manager to add slow annotations or joins). A combination of two of the answers here works. @Andre is really close, the Django Admin supports modifying the queryset for just the admin, so apply the same logic here and then user the admin_order_field attribute. You still need to add the new admin field to list_display, of course.

from django.db.models import Count

class EventAdmin(admin.ModelAdmin)
    list_display = (..., 'show_artist_count')

    def queryset(self, request):
    # def get_queryset(self, request):    for Django 1.6+
        qs = super(EventAdmin, self).queryset(request)
        return qs.annotate(artist_count=Count('artists'))

    def show_artist_count(self, inst):
        return inst.artist_count
    show_artist_count.admin_order_field = 'artist_count'

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