我有以下模式:
class Book < ActiveRecord::Base
has_many :chapters
end
以及
class Chapter < ActiveRecord::Base
belongs_to :book
end
www.un.org/chinese/sc/presidency.asp 我
undefined method `book for #<ActiveRecord::Relation:0x0000010378d5d0>
当我试图获得类似书籍时
@chapter.book
参看“......”。 如果“......章”是初步的,那么:
@chapter = Chapter.where(:id => params[:id])
那么,你就获得一个相对物体(可视为一种收集,但并非单一物体)。 因此,为了确定这一点,你需要检索find_by_id的记录,或首先从收集中获得记录。
@chapter = Chapter.where(:id => params[:id]).first
或
@chapter = Chapter.find_by_id(params[:id])
正如其他人所说的那样,增加<代码>。 我在用独一无二的国际发展法来打一chapter的时候,经历了这一问题。 添加<条码>。
Try: chapter.find (params [:id].first
我也看到类似的错误。
Books.chapters
NoMethodError: undefined method `chapters for #<Book::ActiveRecord_Relation:0x00007f8f9ce94610>
我所需要的是:
Books.includes(:chapters)
collection_select and select Rails helpers: Which one should I use? I can t see a difference in both ways. Both helpers take a collection and generates options tags inside a select tag. Is there a ...
We ve deployed our rails app to EC2. In our setup, we have two proxies on small instances behind round-robin DNS. These run nginx load balancers for a dynamically growing and shrinking farm of web ...
As part of a web application I need an auth-code to pass as a URL parameter. I am currently using (in Rails) : Digest::SHA1.hexdigest((object_id + rand(255)).to_s) Which provides long strings like : ...
I ve installed RubyCAS-Client version 2.1.0 as a plugin within a rails app. It s working, but I d like to remove the ?ticket= in the url. Is this possible?
I have a these 3 models: class User < ActiveRecord::Base has_many :permissions, :dependent => :destroy has_many :roles, :through => :permissions end class Permission < ActiveRecord::...
I m building an xml document from a hash. The xml attributes need to be in order. How can this be accomplished? hash.to_xml
guys which text editor is good for Rubyonrails? i m using Windows and i was using E-Texteditor but its not free n its expired now can anyone plese tell me any free texteditor? n which one is best an ...
I’m developing an application dedicated to generate statistical reports, I would like that user after saving their stat report they save sql queries too. To do that I wrote the following module: ...