`filter(category_slug=category)` 是什么意思？

Question

我有以下 models.py 设置，

class PostList(RoutablePageMixin, Page):
    template = "Post_List.html"
    intro = RichTextField(blank=True)
    content_panels = Page.content_panels + [
        FieldPanel("intro")
        ]

    subpage_types = [
        "PostDetail",
    ]

    parent_page_type = [
        "HomePage",
    ]

    def get_context(self, request, *args, **kwargs):
        context = super().get_context(request, *args, **kwargs)
        context['posts'] = self.posts    
        context['post_list'] = self
        return context

    def get_posts(self):
        return PostList.objects.descendant_of(self).live()


    @route(r'^tag/(?P<tag>[-\w]+)/$')
    def post_by_tag(self, request, tag, *args, **kwargs):
        self.search_type = 'tag'
        self.search_term = tag
        self.posts = self.get_posts().filter(tag__slug=tag)
        return Page.serve(self, request, *args, **kwargs)

    @route(r'^category/(?P<category>[-\w]+)/$')
    def post_by_category(self, request, category, *args, **kwargs):
        self.search_type = 'category'
        self.search_term = category
        self.posts = self.get_posts().filter(category__slug=category)
        return Page.serve(self, request, *args, **kwargs)

    @route(r'^$')
    def post_list(self, request, *args, **kwargs):
        self.posts = self.get_posts()
        return Page.serve(self, request, *args, **kwargs)

问：我不明白filter(category__slug=category)中的category__slug是什么意思？根据field lookup in Django official doc，我从未见过这样的过滤器，只看到xxx__gt或xxx__exact等

Answer 1

I do not understand what does category__slug mean in filter(category__slug=category).

这意味着我们正在过滤 post 个对象的 category 的 slug 字段。 __slug 因此不是查找，它是 Category 模型的一个字段。因此，该模型将如下所示：

class Category(models.Model):
    <strong>slug</strong> = models.SlugField()
    # …

class Post(models.Model):
    <strong>category</strong> = models.ForeignKey(Category, on_delete=models.CASCADE)
    # …

因此我们将进行如下查询：

SELECT post.*
来自 post
INNER JOIN 类别开启 post.category_id = category_id
WHERE category.slug = <em>类别变量值</em>

`filter(category_slug=category)` 是什么意思？

What does `filter(category_slug=category)` mean?

django-queryset

wagtail