蒙哥德，belongs_to和embedded_in热能行吗？

Question

我有三个模型:用户，图片，和喜欢

其中：

class Picture
    include Mongoid::Document
    embeds_many :likes
    belongs_to :user
end
class User
    include Mongoid::Document
    has_many :pictures
    has_many :likes
end
class Like
    include Mongoid::Document
    belongs_to :user
    embedded_in :picture
end

不，我想把喜欢的东西储存起来：

• 看看有多少人喜欢有一张照片( Picture.first.likes.count )
• 看看一个用户有多少喜欢( User.first.likes.count )
• 看看用户制作的是什么样的图片？

实现这三个要求的架构正确吗？

Answer 1

首先，嵌入模型不能在其他地方引用，就像您已经尝试过在用户中引用like (已经嵌入在图片中)一样。

正确的模型结构将是

class Picture
    include Mongoid::Document
    has_and_belongs_to_many :likers, :class_name => "User", :inverse_of => nil
    belongs_to :user
end

class User
    include Mongoid::Document
    has_many :pictures
end

现在回答您的问题

# See how many likes have a picture
Picture.first.likers.count
# See how many likes a user has
# (assumption - will have only one like from one user for a specific picture)
Picture.where(:liker_ids => User.first).count
# See to what picture the user make a like?
Picture.where(:liker_ids => User.first).all