Rails - 爲什麼在這種情況下Eager加載不起作用？

Question

我有這3款具有的has_many通過關係：

class Wine < ActiveRecord::Base 
    has_many :varietals, :conditions => "varietals.status = 1" 
    has_many :grapes, :through => :varietals 
end 

class Grape < ActiveRecord::Base 
    has_many :varietals 
    has_many :wines, :through => :varietals 
end 

class Varietal < ActiveRecord::Base 
    belongs_to :wine 
    belongs_to :grape 
end 

@records = Wine.where(conditions).includes({:varietals => :grape}) 

但是，如果我有10種葡萄酒，我會看到我的日誌10個請求像這些的主要葡萄酒請求後：

Grape Load (0.6ms) SELECT `grapes`.* FROM `grapes` INNER JOIN `varietals` ON `grapes`.id = `varietals`.grape_id WHERE ((`varietals`.wine_id = '98DF2CEC-61CC-4B22-B40D-620AADF650D2') AND ((varietals.status = 1))) 

如何在主要請求中加載葡萄，以避免每個葡萄的請求？

Answer 1

試試這個：

Wine.includes(:varietals).includes(:grapes).where(conditions) 

如果一切正常，不要問我爲什麼）