model-associations

I have one Backbone model which has an attribute that is a reference to another Backbone model. For example, a Person has a reference to an Address object. Person FirstName LastName Address Street City State Zip These are classes that extend the Backbone model. So, then if I construct an object like the following... var address = new Address({ Street: "123 Main", City: "Austin" }); var person = new Person({ FirstName: "John", Address: address }); I cannot seem to figure out how to access it in my Mustache template. Hi {{FirstName}}, you live in {{Address.City}}. Obviously does not work. When I

I'm having a hard time figuring out how to association one of my models with multiple of another. As it is now, I have: class ModelA < ActiveRecord::Base has_many :model_b end class ModelB < ActiveRecord::Base belongs_to :model_a end However... ModelB needs to belong to not only one instance of ModelA, but possibly three. I know there is a has_many :through, but I'm not sure how it would work in this case. EVERY instance of ModelA will always have exactly three instances of ModelB. But as said before, ModelB can belong to more than just one instance of ModelA. Many-to-many relationships in

I am working on a User model, and each user should be able to have both students and teachers. However, since student and teacher are both a type of User , my model got a little complicated. This is what I am trying right now. Teacher_student_link class TeacherStudentLink < ActiveRecord::Base attr_accessible :student_id, :teacher_id, :user_id belongs_to :user belongs_to :teacher, :class_name => "User" belongs_to :student, :class_name => "User" end User class User < ActiveRecord::Base has_many :teacher_student_links, :foreign_key => { :student_id, :teacher_id }, :dependent => :destroy has_many

I am trying to set up some dynamic Dropdown Select Menus in a Search Form using form_tag. What I would like is similar functionality to the example found at Railcasts #88 Models: class Count < ActiveRecord::Base belongs_to :host end class Host < ActiveRecord::Base belongs_to :site has_many :counts end class Site < ActiveRecord::Base belongs_to :state has_many :hosts end class State < ActiveRecord::Base has_many :sites end View: <%= form_tag(counts_path, :method => "get", id: "search-form") do %> <%= select_tag "state_id", options_from_collection_for_select(State.all.order(:name), :id, :name) %

I have an model PointOfContact which has_many Systems . From the Systems side I want to identify the PointOfContact as either the technical_manager or project_manager (or both). While still only keeping the PointOfContact 1 time in the DB. My attempt follows: class System < ActiveRecord::Base belongs_to :project_manager, :class_name => 'PointOfContact' belongs_to :technical_manager, :class_name => 'PointOfContact' end class PointOfContact < ActiveRecord::Base has_many :systems end When I run my specs (example follows) I can correctly create the System point of contact associations. However,

I am reviewing my knowledge in object-oriented programming. Under the relationship between classes topic, I have encountered some relationships which are a bit ambiguous to me. I know dependency "uses-a" and inheritance "is-a" but I'm a bit unfamiliar with Aggregation, Composition, Association and Direct Association; also, which of them is "has-a" relationship. Some use Aggregation interchangeably with Association. What is Direct Association? Also, what is Composition? In UML diagrams, the arrows that represents them are different. I would be really thankful if you could clear these things out

Introduction I'm facing an application design problem with the Ext.data.Model class in ExtJS. I will try to develop my ideas to a very common online store scenario here, so you can follow me. I would really appreciate any comments on my thoughts and conclusions! Models Let's suppose you want to map the fact that " Every customer can order multiple products " to ExtJS. From the bare words one can identify these three models involved: Customer , Order , and Product . The Order in this case is what connects Customer s and Product s. Associations I found that ExtJS actually allows you to specify