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I have two models - Blog and BlogTag. Blog has_many :blog_tags and BlogTag belongs_to :blog: blog.rb has_many :blog_tags blog_Tag.rb belongs_to :blog I want to query the database to select all blogs that have tags matching in the blog_tags table based on what a user enters in a form field. Something like this: Blog.where(blog_tags contain [array of tags]) Is there a way to do this with ActiveRecor
Railsã¢ããªã«ã¦è«çåé¤ã¨eager_loadãåããã¦ä½¿ãã¨N+1åé¡ãçºçãããã¨ã«æ°ã¥ããã®ã§ã¡ã¢ã N+1åé¡ã確èªãã ã¾ãã¯N+1åé¡ãèµ·ãããããªã¢ãã«ãä½æãã¾ããããããããã°ã¢ããªã®ãããªãããã°ã®ã¨ã³ããªããããããã«ã³ã¡ã³ããè¤æ°ãããã¿ã¼ã³ã§ãã class Post < ActiveRecord::Base attr_accessible :title, :content has_many :comments end class Comment < ActiveRecord::Base attr_accessible :post_id, :name, :content belongs_to :post end é©å½ãªãã¼ã¿ãå ¥ããå¾ãããã«å¯¾ãã¦rails cã§ä»¥ä¸ã®ããã«ã¬ã³ã¼ããåå¾ãã¾ãã Post.all.each do |post| puts po
ActiveRecordã§ã¯joinsã¡ã½ãããå©ç¨ãã¦ãinner joinãããã¨ãã§ããã ä¾ï¼ Blog.joins(:article) #=> SELECT "blogs".* FROM "blogs" INNER JOIN "articles" ON "articles"."blog_id" = "blogs"."id" ããã§ãåé¡ã«ãªãã®ã¯"blogs".*ã§ãããarticlesã®æ å ±ã¯ã¨ãã¦ããªãã Includes Vs Joins in Rails - Nikhil Lingutla ãã£ã¦ãä¸è¨ã§è§£èª¬ããã¦ããããã«ã.selectããã§ã¼ã³ãã¦ãããªãã¨ãããªãã 極ãã¦åç´ãªè§£æ±ºçã¨ãã¦ã¯ã以ä¸ã®scopeãä½æãã¦ããã°è¯ãã scope :joins_get_all_columns, ->(*tables) { joins(*tables).select(
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class Blog has_many :posts attr_accessible :enable end class User has_many :posts attr_accessible :enable end class Post belongs_to :blog belongs_to :user end Blog(enable=true)ãããã¯User(enable=true)ã«å±ããPostãåå¾ãããã¨ã MySQLã§æ¸ãã¨ããããªæãã SELECT `posts`.* FROM `posts` LEFT JOIN `blogs` ON `blogs`.`id` = `posts`.`blog_id` LEFT JOIN `users` ON `users`.`id` = `posts`.`user_id` WHERE `blogs`.`enable` = 1 OR `
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