similar to: Serializing has_many associations and ActiveRecord objects

Given the models Country, State, City and Person as follows. class Country < ActiveRecord::Base has_many :states end class State < ActiveRecord::Base belongs_to :country has_many :cities end class City < ActiveRecord::Base belongs_to :state has_many :people end class Person < ActiveRecord::Base belongs_to :city end Is there any way that doesn''t allow to delete

Considering an object with several has_many :through => associations, what is the ''best'' way to handle validations? As an example: class Student < ActiveRecord::Base # some attrbutes like # :name # :grade # relationships has_many :students_assignment, :dependent => :destroy has_many :assignments, :through => :students_assignment has_many

I''m trying to figure out an elegant way to do this: I have the following three tables: people, employer, employees And consequently the following three models: class Person < ActiveRecord::Base end class Employer < ActiveRecord::Base has_many :employees end class Employee < ActiveRecord::Base belongs_to :person belongs_to :employer end I want to be able to say:

Is there a way for me to do: OrderItem.find(:all, :include => [:user, :product => [:supplier]] So I don''t have a supplier_id on my order_item, but have it on my product, which is part of order_item. Joerg -- Posted via http://www.ruby-forum.com/.

I am still using Rails 1.0... I have a simple has_many association: class Round < ActiveRecord::Base has_many :scores end class Score < ActiveRecord::Base belongs_to: round end When I do something like this (contrived for the sake of clarity): rr = Round.find(params[:id]) rr.scores.each { |s| logger.debug("object_id=#{s.round.object_id}") } I see a database query on

Hi. I have a couple of best practices questions regarding polymorphic associations, naming join tables and user permissions. Currently I have implemented the user authentication model from the rails recipes book. Basically it goes something like this: MODEL CLASSES: class User < ActiveRecord::Base has_and_belongs_to_many :roles end class Role < ActiveRecord::Base

Hi everyone. I''ve made a default change to has_many :through associations that I felt was important to make before they''re released. This is after some tickets and confusion I''ve seen regarding has_many :through. class Connection < ActiveRecord::Base belongs_to :user belongs_to :channel end class Channel < ActiveRecord::Base has_many :connections

My question is whether the rails helper methods for handling associations can be nested (see examples below). I suspect not as currently I''m getting "unknown method" if I try and use two associations in one call. The essence of the code is class User << ActiveRecord::Base has_many :items class Items << ActiveRecord::Base has_many :reservations belongs_to

Hi I have a table where I need to identify one of the children as the "prime" child. So, its like: Parent has_many :Child has_one: Child :as :prime_child (?) or something like that? Do I put something like prime_child_id in the Parent table? Thanks. -- You received this message because you are subscribed to the Google Groups "Ruby on Rails: Talk" group. To post to this

I have these 3 models. class Ivr < ActiveRecord::Base has_many :klusterings, :dependent => :destroy has_many :klusters, :through => :klusterings, :uniq => true end class Kluster < ActiveRecord::Base has_many :klusterings, :dependent => :destroy has_many :ivrs, :through => :klusterings, :uniq => true end class Klustering < ActiveRecord::Base belongs_to :kluster

Can someone clarify this for me? Suppose I have two tables like: class Company < ActiveRecord::Base belongs_to :category end class Category < ActiveRecord::Base has_many :companies end I understand that the belongs_to causes related companies to be read from the db when I ask for a category. I suspect SQL something like select * from categories, companies where category.id

What is the most elegant way to save new one-many associations? order = Order.new(:name => "My Order") order.line_items << LineItem.new(:product_id => 1, :quantity => 2) order.line_items << LineItem.new(:product_id => 2, :quantity => 5) order.save The above - which is by far the most elegant way of putting it - doesn''t work for me - the line_items

Hello, I have a Company that has_and_belongs_to_many Persons. A Person has_many Emails. I want to display each Person''s Email for each Company, so I try this: companies = Company.find(:all) for company in companies persons = company.persons for person in persons puts person.email end end Unfortunately, this doesn''t work correctly. Let''s say the id of

I have the following associations. class Document < ActiveRecord::Base has_many :document_sections, :dependent => :destroy, :autosave => true has_many :document_items, :through => :document_sections end class DocumentSection < ActiveRecord::Base belongs_to :document has_many :document_items, :dependent => :destroy, :autosave => true end class DocumentItem <

I have a model layer containing Movie, Person, Role, and RoleType, making it possible to express facts such as "Clint Easterbunny is director of the movie Gran Milano". The relevant model and associations look like this class Movie < ActiveRecord::Base has_many :roles, :include => :role_type, :dependent => :destroy has_many :participants, :through => :roles, :source

Hi all, I have some problems with a few temporary objects, this is the relation between them: A -(1,n)-> B -(1,1)-> C B -(1,n)-> D C -(1,n)-> D I have a "wizard" to create "A" objects, I''m storing everything in the session, something like this: a = A.new session[:a_object] = a ... b = B.new b.c = some_c_instace a.bs << b ... d = D.new b.ds

Is there some sort of good pattern for dealing with computed values with Rails/ActiveRecord? A simple example: 3 tables, classes, students, and student_class_records (habtm style relation but contains a good deal of additional state so is modeled explicitly) Something like select the 10 classes with the most students. Easy enough in SQL. So I''m using a lot of find_by_sql and

A while back, I had some doubts on the use of associations. I still haven''t got a satisfactory guidance so that I can spring ahead with the project. I am trying to understand from a ruby point of view on doing things. Basically I have a controller that gives me a list of students. And each student may have say home address and mailing address. Hence I can model as shown below. How do I

Hello, I found an interesting ER diagram on the "Module: ActiveRecord::Associations::ClassMethods" page of the Rails Framework Documentation : http://ar.rubyonrails.org/classes/ActiveRecord/Associations/ClassMethods.html At the beginning we can read ? Associations are a set of macro-like class methods for tying objects together through foreign keys. They express relationships like

Hi, I need to download an image, and I''ve mucked about with Net::HTTP resp = Net::HTTP.get_response(''www.mydomain.com'', ''/test.jpg'') f = File.new("test.jpg","w") f.write(response.body) And various other combinations using HTTP.get etc. Anyway, I get an image, but it looks very psychedelic. This is obviously not the correct way.