class SystemMessage < ActiveRecord::Base attr_accessible :content, :id, :user_id, :description, :subject belongs_to :user validates :subject, presence: true # validates :description, presence: true validates_length_of :description, maximum: 10000 has_many :message_alls, :class_name => 'MessageAll',:as =>:message, :dependent => :destroy # 系统消息放置总消息列表 after_create :add_system_message def add_system_message if MessageAll.where("message_type = '#{self.class.to_s}' and message_id = '#{self.id}'").first.nil? self.message_alls << MessageAll.new(:user_id => self.user_id) end end end