使一个相当复杂的 Django 模型方法可以在管理中排序？
我有一个相当复杂的自定义 Django 模型方法。它在管理界面中可见，我现在想让它在管理界面中也可排序。
我已按照建议添加了 admin_order_field 在上一个问题中，但我不完全明白我还需要做什么。
class Book(models.Model):
id = models.IntegerField(primary_key=True)
title = models.CharField(max_length=200)
library_id = models.CharField(max_length=200, unique=True)
def current_owner(self):
latest_transaction = Transaction.objects.filter(book=self)[:1]
if latest_transaction:
if latest_transaction[0].transaction_type==0:
return latest_transaction[0].user.windows_id
return None
current_owner.admin_order_field = 'current_owner'
目前，当我单击管理界面中的 current_owner 字段时，Django 会给出我
FieldError at /admin/books/book/
Cannot resolve keyword 'current_owner' into field
是否也需要创建一个 BookManager？如果是这样，我应该使用什么代码？这不是像上一个问题中的示例那样的简单计数，因此我们将不胜感激:)
谢谢！
I have a reasonably complex custom Django model method. It's visible in the admin interface, and I would now like to make it sortable in the admin interface too.
I've added admin_order_field as recommended in this previous question, but I don't fully understand what else I need to do.
class Book(models.Model):
id = models.IntegerField(primary_key=True)
title = models.CharField(max_length=200)
library_id = models.CharField(max_length=200, unique=True)
def current_owner(self):
latest_transaction = Transaction.objects.filter(book=self)[:1]
if latest_transaction:
if latest_transaction[0].transaction_type==0:
return latest_transaction[0].user.windows_id
return None
current_owner.admin_order_field = 'current_owner'
Currently, when I click on the current_owner field in the admin interface, Django gives me
FieldError at /admin/books/book/
Cannot resolve keyword 'current_owner' into field
Do I need to make a BookManager too? If so, what code should I use? This isn't a simple Count like the example in the previous question, so help would be appreciated :)
Thanks!
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Django 管理员不会根据方法的结果或任何其他不是模型字段（即数据库列）的属性对模型进行排序。排序必须在数据库查询中完成，以保持简单高效。
admin_order_field的目的是将非字段属性的排序等同于字段属性的排序。例如，有效值
current_owner.admin_order_field可以是id、title或library_id。显然，这些对您的目的来说都没有意义。一种解决方案是非规范化并始终将
current_owner存储为Book上的模型字段；这可以使用信号自动完成。The Django admin won't order models by the result of a method or any other property that isn't a model field (i.e. a database column). The ordering must be done in the database query, to keep things simple and efficient.
The purpose of
admin_order_fieldis to equate the ordering of a non-field property to the ordering of something that is a field.For example, a valid values
current_owner.admin_order_fieldcould beid,titleorlibrary_id. Obviously none of these makes sense for your purpose.One solution would be to denormalise and always store
current_owneras a model field onBook; this could be done automatically using a signal.你不能这样做。
admin_order_field必须是一个字段，而不是一个方法 - 它适用于当您有一个返回基础字段的自定义表示形式的方法时，而不是当您进行动态计算来提供值时。 Django 的管理使用 ORM 进行排序，并且不能对自定义方法进行排序。You can't do this.
admin_order_fieldhas to be a field, not a method - it's meant for when you have a method that returns a custom representation of an underlying field, not when you do dynamic calculations to provide the value. Django's admin uses the ORM for sorting, and that can't sort on custom methods.