Extending a subclass from an abstract class

rubyonrails-talk
1

Hi,

I have a question regarding to extend a subclass from an abstract class.

Suppose I have an abstract class which has 3 properties in the table:

// event.rb class Event < ActiveRecord::Base    self.abstract_class = true end

// event migration class CreateEvents < ActiveRecord::Migration   def change     create_table :events do |t|       t.string :name       t.string :address       t.string :telephoneNumber

      t.timestamps     end   end end

If I want to extend this class from this event class, say a Party class:

// party.rb class Party < Event end

and it has 1 properties in its own party table.

My question is that is there a way in Rails so that I can carry those 3 properties from the Event class to the Party class?

The problem is that I don't know how to carry out the parent properties to the child class automatically. Or do I need to type all the parent properties everytime I need to extend from the abstract class (this sounds painful...)

Thanks, Kahou

2

Hi,

If I want to extend this class from this event class, say a Party class:

// party.rb class Party < Event end

and it has 1 properties in its own party table.

My question is that is there a way in Rails so that I can carry those 3 properties from the Event class to the Party class?

The problem is that I don't know how to carry out the parent properties to the child class automatically. Or do I need to type all the parent properties everytime I need to extend from the abstract class (this sounds painful...)

You have a few choices: - if you do use an abstract class then yes, for each subclass you'll need to create the table for the subclass - you could switch to single table inheritance: all the subclasses share the same table - maybe you don't want inheritance at all, e.g. maybe your various classes should belong_to some common model

Fred