Question

我目前的数据库结构是我有许多标签的地方。我希望能够搜索包含用户输入搜索框的所有标记的位置。我当前的代码看起来像这样，它只会找到至少有一个指定标签的地方：

tags = params[:tags]

Place.find(:all, :include => [:tags], :conditions => ['tags.title IN (?)', tags])

Answer 1

试试这个：

tags = params[:tags]

Place.find(:all, :include => [:tags], :conditions => ['places.id IN
  (SELECT place_id FROM 
    (SELECT place_id, count(place_id) AS tags_count FROM places_tags WHERE tag_id IN
      (SELECT id FROM tags WHERE title IN (?))
    GROUP BY place_id) AS count_table
   WHERE tags_count = ?)', tags, tags.size])

说明：首先找到数组中的所有标签，然后计算每个地方找到的次数（相当于匹配了多少个标签），然后只选出所有标签匹配的地方。

Answer 2

如果你使用的是标签和Ruby on Rails，我强烈推荐acts_as_taggable_on。

这可以让你做到这样的事情：

class User < ActiveRecord::Base
  # Alias for <tt>acts_as_taggable_on :tags</tt>:
  acts_as_taggable
  acts_as_taggable_on :skills, :interests
end

@user = User.new(:name => "Bobby")
@user.tag_list = "awesome, slick, hefty"      # this should be familiar
@user.skill_list = "joking, clowning, boxing" # but you can do it for any context!
@user.skill_list                              # => ["joking","clowning","boxing"] as TagList
@user.save

@user.tags # => [<Tag name:"awesome">,<Tag name:"slick">,<Tag name:"hefty">]
@user.skills # => [<Tag name:"joking">,<Tag name:"clowning">,<Tag name:"boxing">]

@frankie = User.create(:name => "Frankie", :skill_list => "joking, flying, eating")
User.skill_counts # => [<Tag name="joking" count=2>,<Tag name="clowning" count=1>...]
@frankie.skill_counts

非常容易实施。而且您不必担心如何在数组中查找特定元素。

查找包含数组所有元素的条目

2 个答案: