验证属性并通过关系has_many

Question

我有以下结构：

class FundFilter < ActiveRecord::Base
  has_many :fund_filter_users, dependent: :destroy
  has_many :users, through: :fund_filter_users
end
class FundFilterUser < ActiveRecord::Base  
  belongs_to :fund_filter
  belongs_to :user
end
class User < ActiveRecord::Base
  has_many :fund_filter_users, dependent: :destroy
  has_many :fund_filters, through: :fund_filter_users  
end

我需要的是一个fund_filter 的 ：name 上的验证器，它不能为单个用户重复。对于FundFilterUser中的单个user_id的含义，我需要检查该基金过滤器的：name不重复的所有fund_filter_ids。

想法？

Answer 1

可以实现一个自定义验证器，用于检查与用户关联的fund_filters中的重复名称。

它可能看起来像这样：

class User < ActiveRecord::Base
  has_many :fund_filter_users, dependent: :destroy
  has_many :fund_filters, through: :fund_filter_users  
  validate :fund_filters, has_uniq_name
  def has_uniq_name
    all_fund_filter_from_user = []
    fund_filter_users.each do |fund_filter_user|
      all_fund_filter_from_user = all_fund_filter_from_user.concat(fund_filter_user.fund_filters)
    end
    errors.add(:fund_filters, "cannot have repeated names") unless all_fund_filter_from_user.collect{|p| p.name}.uniq.length == all_fund_filter_from_user.length
  end
end