Question

我正在使用rails 4中的项目，其中用户可以拥有多个项目，并且许多人与单个项目相关联。即。项目和用户分享了多对多的关系。

我使用此迁移代码创建了一个新表 -

class CreateProjectsUsersJoin < ActiveRecord::Migration
  def change
    create_table :projects_users_joins, :id => false do |t|

        t.integer :user_id
        t.integer :project_id
    end

    add_index :projects_users_joins, ["user_id","project_id"]
  end
end

并以下列方式添加关联 -

class Project < ActiveRecord::Base

    validates :name , :presence => true
    validates :description, :presence => true


    #associations
    has_and_belongs_to_many :users

end


class User < ActiveRecord::Base

    include CarrierWave::MiniMagick

    #removes the white spaces before validating the data 


    before_validation :strip_whitespace, :only => [:name,:email]

    #data validations
    validates :email, :presence =>true,  :uniqueness => {case_sensitive: false}, :format => { :with=> /([a-zA-Z0-9_\-\.]+)@((\[[0-9]{1,3}\.[0-9]{1,3}\.[0-9]{1,3}\.)|(([a-zA-Z0-9\-]+\.)+))([a-zA-Z]{2,4}|[0-9]{1,3})(\]?)/, :message => "please enter a valid e-mail" }
    validates :name, :presence=>true
    validates :password ,:presence =>true, :confirmation=> true #, :length =>{ :minimum=>6, :maximum=>30}, :format=>{:with=>/(?=.*\d)(?=.*[a-z])(?=.*[A-Z]).{6,30}/}

    #for the image
    mount_uploader :image, ImageUploader

    #for the password
    has_secure_password


    #associations
    has_many :issues
    has_many :comments
    has_and_belongs_to_many :projects

end


    #squishes the data(removes heading and trailing  white spaces and replaces multiple space by songle)
def strip_whitespace
    self.email = self.email.squish
    self.name = self.name.squish
end

当我在rails控制台上运行以下命令时，我得到一个no方法错误 - 请帮忙

pro = Project.find(1)  (works)
me = User.find(27) (works)
pro.users << me  (throws a no method defined error)

请帮忙

Answer 1

你的表名错了。 As the docs say默认连接表名称应该只是用下划线连接的词法顺序中的两个类的复数名称。在这种情况下projects_users。

如果您需要projects_users_joins，那么您可以在:join_table次调用中提供habtm选项，或者（我的推荐）执行该rake db:migrate:down次迁移，然后删除"_joins"并再次迁移以生成默认表名。

没有方法错误

1 个答案: