belongs-to

问题 What is the ember-cli best practice to deleteRecord() on a model that belongsTo multiple models? Do I have to manually clean up relationships on the parents? Migrating from ember to ember-cli I am having new trouble with deleteRecord() for a model 'star' that belongsTo multiple models, 'post' and 'user'. Before moving to ember cli it was working with this solution. The previous solution's delete action fails in the current ember-cli with errors and never calls the api . TypeError: Cannot read

问题 I have an application which has the following characteristics There are Clubs Each Club has Teams Each Team has Players I have a users table. The user table basically contains the username and password for the club manager, team manager and the player to login to the system. How should I structure the models and the tables? I plan to create tables for Club, Team and Players. But I am not sure show to structure the relationship between them and the users table. I could create user_id in each

问题 Let's imagine I run an imaginary art store with a couple models (and by models I'm referring to the Rails term not the arts term as in nude models) that looks something like this: class Artwork < ActiveRecord::Base belongs_to :purchase belongs_to :artist end class Purchase < ActiveRecord::Base has_many :artworks belongs_to :customer end The Artwork is created and sometime later it is included in a Purchase . In my create or update controller method for Purchase I would like to associate the

问题 I'm inheriting code which has: class Graphic < ActiveRecord::Base has_many :comments, :foreign_key => 'asset_id', :conditions => 'asset_type_id = 5', :order => 'created_at', :dependent => :destroy class Comment < ActiveRecord::Base belongs_to :graphic, :foreign_key => :asset_id It seems to me like the has_many should not have the foreign_key (it's referenced in the belongs_to ok I believe) but I am not sure, do you know? i.e. should it be class Graphic < ActiveRecord::Base has_many :comments,

问题 I've come across this rather odd bit of behaviour in a rails application I'm working on. I have multiple types of Post in an inheritance heirarchy, and a Post has_many FeedEntries. class Post < ActiveRecord::Base has_many :feed_entries end class Post::BlogPost < Post; end class Post::Discussion < Post; end class Post::Article < Post; end class FeedEntry < ActiveRecord::Base belongs_to :post end Now, when I have everything set up as before, calling FeedEntry#post on a saved object always

问题 I have an Object, Ball, which belongs_to a Girl, which can have_many balls. Everything works for the most part, but if I try to print out the girls' name via: @balls.each do |b| b.girl.name end I get the following error: "undefined method `name' for nil:NilClass" Which really confuses me. If I say b.girl.class, I get it as an instance of Girl, just fine. That is, it isn't "NillClass". Not only that, if I just try it for any Ball, and say @ball.girl.name I'm perfectly fine. What is it about a

问题 I'm trying to map the column names of this class: class Amount{ String total //Total amount of something String type //Type of amount, Dollars, %, Times something Bonification bonificationRate //the amount can be "x times another bonification" static belongsTo = [parentBonification: Bonification] static mapping = { table "AMOUNTS" total column: "AMOU_TTOTAL" type column: "AMOU_TTYPE" parentBonification column: "BONI_CID" bonificationRate column: "BONI_TRATE_CID" } } class Bonification { /

问题 I am studying Belongs_to association, I have used following models, in that every order belongs to the customer, so I have used belongs_to in order model it giving error while creating order undefined method `orders' for # when I use has_many :orders in customer model it works fine, why it does not work with only belongs_to Its work with has_many :orders in customer model but not with has_one : order in customer controller it giving same above error. thanks in advance. Model :- order.rb class

问题 A phone has many messages. An email address has many messages. A message either belongs to a phone, email, or neither. The belongs_to association is optional. The following associations seem to work fine for these relationships: Phone model has_many :messages Email model has_many :messages Message model does NOT have belongs_to :phones, :email Is this okay or is there some proper way to specify a "can_belong_to" relationship? 回答1: It is completely correct unidirectional relation. Using both

问题 I'm trying to create a 'tag' functionality which allows a user to "tag" items in which they are interested. Here is my model class tag belongs_to :user belongs_to :item end The corresponding DB table has the necessary :user_id and :item_id fields. In the list of :items I want a link next to each :item that allows the user to tag the :item . Since I know the :user_id and the :item_id , I want to create a new :tag record, set the id fields, and save the record - all with no user intervention. I