如何获取用户在 SQL 或 Ruby 中评论的页面上的最新评论？

Posted 2023-04-15

【中文标题】如何获取用户在 SQL 或 Ruby 中评论的页面上的最新评论？

【英文标题】：How to get recent comments on pages that the user commented on in SQL or Ruby?

【发布时间】：2014-03-20 16:12:49

【问题描述】：

如何以优化的方式为用户获取所有相关的 cmets？ 相关评论是对用户保存的页面和/或用户评论的页面上的（最近）评论。下面是我当前的代码，但它很长而且不是最优的。我该如何修复它，无论是使用 Ruby 还是 SQL，它都可以快速返回 cmets？

def self.relevant_comments(user)
    recent_comments = Comment.newest.first(50) #check through 50 most recent comments 
    saved_pages = user.saved_pages.to_set #get all of user's saved pages
    commented_pages =  Set.new
    user.comments.each |comment| commented_pages.add comment.page  #get all the pages of user's comments

    #now go through the sets and put the relevant comments into `comments` 
    comments = Set.new
    recent_comments.each do |comment|
        page = comment.page
        comments.add(comment) if saved_pages.include?(page) or commented_pages.include?(page)
        break if comments.size >= 10
    end

    return comments
end

【参考方案1】：

尝试对页面进行预过滤，如下所示：

def self.relevant_comments(user)
    recent_comments = Comment.newest.first(50) #check through 50 most recent comments 
    recent_page_ids = recent_comments.map(&:page_id)
    saved_pages = user.saved_pages.where(id: recent_page_ids).to_set #get all of user's saved pages
    commented_pages =  Set.new
    user.comments.where(page_id: recent_page_ids).each |comment| commented_pages.add comment.page  #get all the pages of user's comments

    #now go through the sets and put the relevant comments into `comments` 
    comments = Set.new
    recent_comments.each do |comment|
        page = comment.page
        comments.add(comment) if saved_pages.include?(page) or commented_pages.include?(page)
        break if comments.size >= 10
    end

    return comments
end