How to design a system like google base with dynamic attributes? in Ruby on Rails

Question

I am wanting to create an application that can allow users to add products for sale.

I want to make it so that a user can add whatever type of product he/she likes and let them also create stored and searchable attributes for their products - alot like google base does.

Does anyone know of the best way to do this ie model it.

I don't really want a table for each category as this would be possibly 1000s of tables.

What is the best way to do this? has anyone got good / bad experiences of this?

Is there any plugins that does this?

Any help would be great

thanks rick

Answer 1

It sounds like what you want is a tag system.

If you want something more flexible you might want to look at using a document store instead of a database, for example CouchDB.

Answer 2

If you don't want to keep this in a relational database I'd suggest creating a Model called "Descriptor" that would contain the ID of the item being added, the name of the attribute "Color" and the value "Red".

To help keeps things consistent you could also structure pre-set groups of descriptors (for cars: make, model, color) as well as provide auto-completes for the value entry text fields.