Rails 3 Abstract Class vs Inherited Class

In my rails 3 model, I have two classes: Product, Service. I want both to be of type InventoryItem because I have another model called Store and Store开发者_开发知识库 has_many :InventoryItems

This is what I'm trying to get to, but I'm not sure how to model this in my InventoryItem model and my Product and Service models. Should InventoryItem just be a parent class that Product and Service inherit from, or should InventoryItem be modeled as a class abstract of which Product and Service extend from.

Thanks in advance for the advice!

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Personally, I would not use inheritance. Why don't you just say

has_many :services
has_many :products

Inheritance is pretty expensive - both in terms of runtime and often in readability too. This case sounds like a very basic case for which no inheritance is required. Do you really want products and services to actually INHERIT something from a base class? What you writes indicates all you want is to establish the association.

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I'd use neither, and follow what Mörre suggested to have InventoryItem be a join model:

class Store
  has_many :inventory_items
  has_many :products, :services, :through => :inventory_items
end

class InventoryItem
  belongs_to :store
  belongs_to :products, :services
end

class Product
  has_many :inventory_items
  has_many :stores, :through => :inventory_items
end

class Service
  has_many :inventory_items
  has_many :stores, :through => :inventory_items
end