associations

问题 Background I have a rails application with deeply nested associations. .-< WorkPeriod Timecard -< Week -< Day -<--< Subtotal `-< Adjustment -< (has many) I'm using Active Model Serializer to build out the API. On the client side I want to load a timecard and all it's associations in one shot. Currently my serializers look like this, class TimecardSerializer < ActiveModel::Serializer embed :ids, include: true has_many :weeks end class WeekSerializer < ActiveModel::Serializer embed :ids,

问题 I've read multiple questions about this, but have yet to find an answer that works for my situation. I have 3 models: Apps , AppsGenres and Genres Here are the pertinent fields from each of those: Apps application_id AppsGenres genre_id application_id Genres genre_id The key here is that I'm not using the id field from those models. I need to associate the tables based on those application_id and genre_id fields. Here's what I've currently got, but it's not getting me the query I need: class

问题 I have no idea what went wrong but I can't get belongs_to work with :class_name option. Could somebody enlighten me. Thanks a lot! Here is a snip from my code. class CreateUsers < ActiveRecord::Migration def self.up create_table :users do |t| t.text :name end end def self.down drop_table :users end end ##################################################### class CreateBooks < ActiveRecord::Migration def self.up create_table :books do |t| t.text :title t.integer :author_id, :null => false end

问题 I am trying to make an app in Rails 4. I just asked this related question and got a clear answer. It seems I can't understand how to take that logic and apply it elsewhere. Rails How to show attributes from a parent object I have a user model, profile model a projects model and a universities model. Associations are: Profile belongs to university Profile belongs to user University has many profiles University has many projects Projects HABTM user Projects belong to universities In my projects

问题 I have 3 models: Question, Option, Rule Question has_many options; Option needs a foreign key for question_id Rule table consists of 3 foreign_keys: 2 columns/references to question_ids -> foreign keys named as 'assumption_question_id' and 'consequent_question_id' 1 column/reference to option_id -> foreign key named as option_id or condition_id Associations for Rule: Question has_many rules; and Option has_one rule I want to understand how to write up migrations for this, and how that

问题 I have a specific request, to build an association between users. This causes me confusion, how to reduce duplicate associations, query and results? The starting point would look like this? // UsersTable $this->belongsToMany('Users', [ 'through' => 'Connections', ]); How to fetch all associations in one query, regardless of whether users key in "user_from" or "user_to" field? 回答1: How about using aliases? Your users table: class UsersTable extends Table { public function initialize(array

问题 Spent a working day on this. I have class Box has_many :users, :through => :subscriptions end I also have custom insert_new_users and associate_with(new_users) methods which use multiple INSERT to do their job quickly. Anyway, they work fine. I also have this line at the end of "associate_with" method: def associate_with # mysql INSERT here self.users(true) # Should force reload end It works as expected when running in test environment (both controller and model tests) and it fails as

问题 I am wondering whether there is a way to do this with rails or not. Basically I have a user model and an event model. Event is created by a user and I want to have a foreign key (user_id) in the event model that indicates who created the event. Additionally, event can have many users who attend it so the event model becomes something like belongs_to :user has_many :users, :through => :guests #suppose i have the guest model and the user model looks something like has_many :events, :through =>

问题 I have two associated business objects - A and B. the association is (A->B)many-to-one, with B.Id a foreign key in A (so A has A.B_id in the DB). I'm using lazy=true and solved most of my problems, however in A's ToString I want to print also A.B.Id, which I should have without further trips to the DB. but accessing A.B activates the proxy, and since this isn't in the context of an open session, throws an exception. one easy but ugly solution would be to have A.B_id property. but that's part

问题 I am having some issues with CakePHP's find() method and conditions in 'deeper' model associations. There are some of these around but I could not find an answer to this so far. My model associations are User hasMany Post hasMany Comment hasMany Vote and Vote belongsTo Comment belongsTo Post belongsTo User respectively. The belongsTo associations use inner joins ('type' => 'INNER'). How do I find all comment votes for posts of a specific user with CakePHP's model->find() method? I used a