我需要一個類變量還是一個實例變量？

Question

我目前有一個名爲owner_id的ActiveRecord模型「團隊」。

owner_id數據只是臨時的，一旦after_create被調用，它將是多餘的。

我想刪除'owner_id'列並整理它，但保持功能正常。我怎樣才能做到這一點？

有關背景：

class Team < ActiveRecord::Base 
    attr_accessible :name, :owner_id, :team_id 
    has_many :team_memberships, :dependent => :destroy 
    has_many :users, through: :team_memberships 
    accepts_nested_attributes_for :team_memberships 

    after_create :create_team_membership 

    private 

    def create_team_membership 
    TeamMembership.create(
     :user_id => self.owner_id, 
     :team_id => self.id, 
     :roles => "site_admin") 
    end 
end 

Answer 1

您應該能夠添加attr_accessor，繼續沒有數據庫列例如分配owner_id屬性Team.new(:owner_id => 7)

class Team < ActiveRecord::Base 
    attr_accessor :owner_id 
end 

您還可以避免明確地分配team_id，如果你想：

class Team < ActiveRecord::Base 
    def create_team_membership 
    team_memberships.create(:user_id => owner_id, :roles => "site_admin") 
    end 
end