Django，哪个功能属于QuerySet和Manager? [英] Django, which function belongs to QuerySet and Manager?

问题描述

我曾经认为QuerySet方法返回QuerySet实例，但显然没有.

I used to think QuerySet method return QuerySet instances, but it apparently not.

例如，count()是一个查询集方法，而不是管理者的

For instance, count() is a queryset method not manager's

我该如何确定哪些函数用于自定义QuerySet，哪些函数用于自定义Manager类?

How do I decide which functions go to custom QuerySet and which go to custom Manager class?

推荐答案

能够访问管理器上的count()和查询集上的某些功能是很有意义的.这使您可以执行以下操作:

It makes sense to be able to access some functions like count() on the manager and the queryset. This allows you to do:

Blog.objects.count()  # total number of blogs
Blog.objects.filter(status='PUBLISHED').count()  # Number of published blogs

Django具有方法 as_manager ，可让您从自定义查询集中创建管理器.这意味着您不必在管理器和查询集上重复您的方法.

Django has a method as_manager which allows you to create a manager from a custom queryset. This means you don't have to duplicate your methods on the manager and queryset.

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