我有一个选民模型加入的用户和问题.用户可以对问题进行投票.他们可以向上或向下投票(在选民模型中记录).首先,我希望能够阻止用户在一个方向上投票.其次,我想允许用户投反对票.因此,如果他们投了票,他们仍然可以投票,这将取代上行投票.用户永远不能对问题进行两次投票.这是我的文件：
class Issue < ActiveRecord::Base
has_many :associations,:dependent => :destroy
has_many :users,:through => :associations
has_many :voterships,:dependent => :destroy
has_many :users,:through => :voterships
belongs_to :app
STATUS = ['Open','Closed']
validates :subject,:presence => true,:length => { :maximum => 50 }
validates :description,:length => { :maximum => 200 }
validates :type,:presence => true
validates :status,:presence => true
def cast_vote_up!(user_id,direction)
voterships.create!(:issue_id => self.id,:user_id => user_id,:direction => direction)
end
end
class Votership < ActiveRecord::Base
belongs_to :user
belongs_to :issue
end
class VotershipsController < ApplicationController
def create
session[:return_to] = request.referrer
@issue = Issue.find(params[:votership][:issue_id])
@issue.cast_vote_up!(current_user.id,"up")
redirect_to session[:return_to]
end
end
class User < ActiveRecord::Base
authenticates_with_sorcery!
attr_accessible :email,:password,:password_confirmation
validates_confirmation_of :password
validates_presence_of :password,:on => :create
validates_presence_of :email
validates_uniqueness_of :email
has_many :associations,:dependent => :destroy
has_many :issues,:through => :voterships
end
解决方法
您可以将唯一性约束放在Votership模型上.您不需要在关联本身上放置验证.
class Votership < ActiveRecord::Base
belongs_to :user
belongs_to :issue
validates :issue_id,:uniqueness => {:scope=>:user_id}
end
这意味着用户只能对给定的问题(向上或向下)进行一次投票.