Ruby on rails 如何修复rails中has_和_属于_的错误
我想在联接表中创建一个记录,但rails在两种情况下显示了两个错误,我不想生成第三个模型Ruby on rails 如何修复rails中has_和_属于_的错误,ruby-on-rails,has-and-belongs-to-many,Ruby On Rails,Has And Belongs To Many,我想在联接表中创建一个记录,但rails在两种情况下显示了两个错误,我不想生成第三个模型 @channel = Channel.find(params[:channel_id]) if @channel.users.create!(channel_id: params[:channel_id], user_id: params[:user_id]) flash[:success] = "U Succeed:)" redirect_to request.referrer e
@channel = Channel.find(params[:channel_id])
if @channel.users.create!(channel_id: params[:channel_id], user_id: params[:user_id])
flash[:success] = "U Succeed:)"
redirect_to request.referrer
else
flash[:danger] = "U Nit Succeed:H"
redirect_to request.referrer
end
第二种情况
if Channel.users.create!(channel_id: params[:channel_id], user_id: params[:user_id])
flash[:success] = "U Succeed:)"
redirect_to request.referrer
else
flash[:danger] = "U'r Not Succeed:H"
redirect_to request.referrer
end
我想在联接表中保存属性。根据rails官方网站指南,出了什么问题
第一个错误:
用户的未知属性“channel\u id”
第二个错误:
类0x00007feaa0312058的未定义方法“users”
我假设你们有这样的联系:
class User < ActiveRecord::Base
has_and_belongs_to_many :channels
end
class Channel < ActiveRecord::Base
has_and_belongs_to_many :users
end
这将尝试创建一个新的User
类对象,因为中间没有模型,只有一个中间表。相反,您可以这样做:
@channel.users.create!(channel_id: params[:channel_id], user_id: params[:user_id])
# If you don't have the user object already
user = User.find params[:user_id]
# This will create a record in the mid table
@channel.users << user
@channel.users = user
Channel.users.create!(channel_id: params[:channel_id], user_id: params[:user_id])
这将从该频道的mid表中删除所有现有关联用户记录,并添加与该用户关联的新记录
当你尝试这样做时:
@channel.users.create!(channel_id: params[:channel_id], user_id: params[:user_id])
# If you don't have the user object already
user = User.find params[:user_id]
# This will create a record in the mid table
@channel.users << user
@channel.users = user
Channel.users.create!(channel_id: params[:channel_id], user_id: params[:user_id])
这根本无效,因为类
频道
与用户
没有任何直接关系,但是频道
类的实例可能与用户
类的实例相关联。对于第一个场景,我建议您像这样做
@channel.user_ids = @channel.user_ids + [params[:user_id]]
它将创建联接表记录,您当然可以根据自己的需要尝试优化方法。您可以使用推送,或者发布每个模型的代码?同样对于第二个场景,对于Class0x00007,它是一个
未定义的方法“users”。
bc关联在通道实例上,而不是类本身。是的,它是相同的代码。这是工作,没有错误。但是用户id和频道id会互相保存,谢谢。这项工作就像上面的解决方案,没有错误,但我提到的同样的问题仍然存在