查找带有文章的标签 [英] Find tags with articles
本文介绍了查找带有文章的标签的处理方法,对大家解决问题具有一定的参考价值,需要的朋友们下面随着小编来一起学习吧!
问题描述
在博客应用中,我想显示文章标签列表.
On blog app I want to display list of tags with articles.
class Article < AR::B
has_and_belongs_to_many :tags
end
class Tag < AR::B
has_and_belongs_to_many :articles
end
标签范围是什么样的?
Tag.joins(:articles) ... # should return tags associated to at least 1 article
推荐答案
使用 Ruby/Rails 做到这一点的一种方法是这个.
One way to do this with Ruby/Rails would be this one.
Tag.includes(:articles).select { |tag|tag.articles.any?}
.includes
确保文章与标签一起加载,这比在迭代每个标签的文章时加载它们更有效.
.includes
makes sure that the articles are loaded alongside the tags, which is more efficient than loading them when every tag's articles are iterated upon.
然后解析数组以仅选择与文章相关联的那些.
The array is then parsed to only select the ones with articles associated.
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