Rails 3在一個查詢中包含多個表格

我正在使用Rails應用程序進行錦標賽。我有三個型號即時通訊與此查詢工作：Rails 3在一個查詢中包含多個表格

class Player < ActiveRecord::Base 
    validates :name, :uniqueness => true 
    has_and_belongs_to_many :tournaments 

class Tournament < ActiveRecord::Base 
    belongs_to :tournament_type 
    has_and_belongs_to_many :players 
    has_many :player_matches, :dependent => :destroy 

class PlayerMatch < ActiveRecord::Base 
    belongs_to :player_one, :class_name => "Player", :foreign_key => "player_one" 
    belongs_to :player_two, :class_name => "Player", :foreign_key => "player_two"

在tournaments_controller的表演動作，即時致電以下查詢：

Tournament.where(:id => params[:id]).includes(:player_matches, :players).first()

雖然比賽和player_matches在一個單一的完成加盟，玩家單獨查詢，因爲我的代碼依賴於他們：

Player Load (0.4ms) SELECT `players`.*, t0.tournament_id as the_parent_record_id FROM `players` INNER JOIN `players_tournaments` t0 ON `players`.id = t0.player_id WHERE (t0.tournament_id = 14) 
Player Load (0.2ms) SELECT `players`.* FROM `players` WHERE `players`.`id` = 5 LIMIT 1 
Player Load (0.2ms) SELECT `players`.* FROM `players` WHERE `players`.`id` = 9 LIMIT 1 
Player Load (0.2ms) SELECT `players`.* FROM `players` WHERE `players`.`id` = 1 LIMIT 1 
Player Load (0.1ms) SELECT `players`.* FROM `players` WHERE `players`.`id` = 8 LIMIT 1 
Player Load (0.1ms) SELECT `players`.* FROM `players` WHERE `players`.`id` = 3 LIMIT 1 
Player Load (0.1ms) SELECT `players`.* FROM `players` WHERE `players`.`id` = 2 LIMIT 1 
Player Load (0.1ms) SELECT `players`.* FROM `players` WHERE `players`.`id` = 7 LIMIT 1 
Player Load (0.1ms) SELECT `players`.* FROM `players` WHERE `players`.`id` = 6 LIMIT 1 
Player Load (0.1ms) SELECT `players`.* FROM `players` WHERE `players`.`id` = 4 LIMIT 1

我怎樣才能改變這件事，所以它是所有在一個查詢拉？

來源

2011-04-01 agmcleod

拋棄它作爲評論類似的東西解決了我的N + 1問題，但我不確定它是否適用於您。如果您將'includes'調用改爲'includes（：player_matches =>：players）'，你會得到什麼？ – 2011-04-01 22:20:50

另外，拋出這個......確保你正在查看生產模式中使用的SQL，而不是開發。 – 2011-04-01 22:37:00

尚未在生產模式下運行。該輸出來自終端中的服務器控制檯，應該是日誌，所以我知道我有正確的輸出:)。 – agmcleod 2011-04-01 23:05:44

Tournament.where(:id => params[:id]).includes([{:player_matches => :player_one}, :players]).first()

這應該做的伎倆。實際上，數組符號和散列符號的組合起初有點麻煩，但是與控制檯一起工作，你會發現哪種語法不會崩潰:)

來源

2011-04-14 14:45:13 nessur

感謝您的回覆。我仍然收到多個玩家查詢回來雖然:(我不知道如果也許我的問題在於我如何使用數據，或者我有如何結構化數據庫。 – agmcleod 2011-04-15 11:16:43

Rails 3在一個查詢中包含多個表格

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