single-table-inheritance

问题 I have two types of classes: BaseUser < ActiveRecord::Base and User < BaseUser which acts_as_authentic using Authlogic's authentication system. This inheritance is implemented using Single Table Inheritance If a new user registers, I register him as a User. However, if I already have a BaseUser with the same email, I'd like to change that BaseUser to a User in the database without simply copying all the data over to the User from the BaseUser and creating a new User (i.e. with a new id). Is

问题 I have two types of classes: BaseUser < ActiveRecord::Base and User < BaseUser which acts_as_authentic using Authlogic's authentication system. This inheritance is implemented using Single Table Inheritance If a new user registers, I register him as a User. However, if I already have a BaseUser with the same email, I'd like to change that BaseUser to a User in the database without simply copying all the data over to the User from the BaseUser and creating a new User (i.e. with a new id). Is

问题 I'm designing a classifieds website about pets that will have 3 (main) categories of ads: A- Sale B- Breeding C- Jobs The problem I'm facing is that all 3 ad categories have some things in common, but they also have some differences. For example, categories A, B and C all have the following in common: category_id ad_id user_id location However, category B ads cannot be classified as "Looking For/For Sale", whereas B & C can. Furthermore, each category will have its own subcategories. For

问题 I am using Entity Framework 6.0.2 with an existing database in which tags are stored in a single table that looks like this: Id : int, primary key TagType : string, determine the type of tag, either "usertag" or "movietag" ItemId : int, contains the Id of the item to which is referred (either a User Id or a Movie Id) The following classes describe this situation: public class User { public int Id { get; set; } } public class Movie { public int Id { get; set; } } public abstract class Tag {

问题 I am using Entity Framework 6.0.2 with an existing database in which tags are stored in a single table that looks like this: Id : int, primary key TagType : string, determine the type of tag, either "usertag" or "movietag" ItemId : int, contains the Id of the item to which is referred (either a User Id or a Movie Id) The following classes describe this situation: public class User { public int Id { get; set; } } public class Movie { public int Id { get; set; } } public abstract class Tag {

问题 I am using Entity Framework 6.0.2 with an existing database in which tags are stored in a single table that looks like this: Id : int, primary key TagType : string, determine the type of tag, either "usertag" or "movietag" ItemId : int, contains the Id of the item to which is referred (either a User Id or a Movie Id) The following classes describe this situation: public class User { public int Id { get; set; } } public class Movie { public int Id { get; set; } } public abstract class Tag {

问题 My Rails views and controllers are littered with redirect_to , link_to , and form_for method calls. Sometimes link_to and redirect_to are explicit in the paths they're linking (e.g. link_to 'New Person', new_person_path ), but many times the paths are implicit (e.g. link_to 'Show', person ). I add some single table inheritance (STI) to my model (say Employee < Person ), and all of these methods break for an instance of the subclass (say Employee ); when rails executes link_to @person , it

问题 We're trying to come up with the data model of Payment Method. There can be several kinds of payment methods like Card, Bank Transfer, Wallet, which further can be categorized for e.g. Card into credit/debit cards, Bank Transfer into ACH/SEPA and the like. So this is about modelling inheritance into database tables. One option is to use single table inheritance. Senior folks in my team call single table as denormalized table. But I don't understand why? I don't see any insert/delete/update

问题 I'm making a Rails 4.0.1 app using Capybara and FactoryGirl but I'm having trouble getting my tests to work correctly. I'm using single table inheritance to make a Collection < ActiveRecord::Base and a VideoCollection < Collection model. When using Factory Girl in my tests, the models don't seem to get instantiated as they should. The Details: When I visually inspect a view in my browser that I'm testing, it displays the collection properly. When I run print page.html in the test for the same

问题 I have implemented single table inheritance for a person class class Person < ActiveRecord::Base end class Teacher < Person end class Student < Person end class Outsider < Person end And the create person seems to work creating Teacher, Student or Person according to the what is chosen in the form.select and the type attribute is added. However, I seem to have broken the routes <%= link_to 'Edit', edit_person_path(@deal) %> | <%= link_to 'Back', persons_path %> They seem to point to teacher