Mongoid验证唯一性与范围和belongs_to

Question

我有以下mongoid模型，范围验证，以防止在一个账单上的多个选票。每票属于用户和组：

 
class Vote 
    include Mongoid::Document 
    field :value, :type => Symbol # can be :aye, :nay, :abstain 
    field :type, :type => Symbol # TODO can delete? 

    belongs_to :user 
    belongs_to :polco_group 

    embedded_in :bill 
    validates_uniqueness_of :value, :scope => [:polco_group_id, :user_id, :type] 

end 

用户有以下方法进行了表决添加到账单：

 
    def vote_on(bill, value)  
    if my_groups = self.polco_groups # test to make sure the user is a member of a group 
     my_groups.each do |g| 
      # TODO see if already voted 
      bill.votes.create(:value => value, :user_id => self.id, :polco_group_id => g.id, :type => g.type) 
     end 
    else 
     raise "no polco_groups for this user" # #{self.full_name}" 
    end 
    end 

和嵌入许多法案类：票。这样做的目的是允许用户将他们的投票与不同的团体（“Ruby编码”，“女性”等）相关联，并且运行良好，除了数据库目前允许用户在一张账单上多次投票。我如何获得以下功能？

 
u = User.last 
b = Bill.last 
u.vote_on(b,:nay) 
u.vote_on(b,:nay) -> should return a validation error 

Answer 1

最有可能的验证器上Vote不会被解雇。您可以通过添加验证功能并输出内容或引发异常来确认。

class Vote 
    validate :dummy_validator_to_confirmation 

    def dummy_validator_to_confirmation 
    raise "What the hell, it is being called, then why my validations are not working?" 
    end 
end 

如果创建上述的验证User#vote_on不会引发异常后，就已经证实回调不通过vote_on方法烧制Vote。您需要更改您的代码以触发Vote上的回调。也许改变它类似于以下，将有助于：

def vote_on(bill, value)  
    if my_groups = self.polco_groups # test to make sure the user is a member of a group 
    my_groups.each do |g| 
     # TODO see if already voted 
     vote = bill.votes.new(:value => value, :user_id => self.id, :polco_group_id => g.id, :type => g.type) 
     vote.save 
    end 
    else 
    raise "no polco_groups for this user" # #{self.full_name}" 
    end 
end 

上有mongoid GitHub上的问题跟踪，使级联回调到嵌入文档的。现在回调只能在正在发生持久性操作的文档上触发。