c# - How do you build extensible data model

Question

I'm thinking of building a ecommerce application with an extensible data model using NHibernate and Fluent NHibernate. By having an extensible data model, I have the ability to define a Product entity, and allow a user in the application to extend it with new fields/properties with different data types including custom data types.

Example: Product can have an addition fields like: Size - int Color - string Price - decimal Collection of ColoredImage - name, image (e.g. "Red", red.jpg (binary file))

An additional requirement is to be able to filter the products by these additional/extended fields. How should I implement this?

Thanks in advance.

Answer 1

I think this link describes kind of what you want...

http://ayende.com/Blog/archive/2009/04/11/nhibernate-mapping-ltdynamic-componentgt.aspx

More info on dynamic-component:

http://www.mattfreeman.co.uk/2009/01/nhibernate-mapping-with-dynamic-component/ http://bartreyserhove.blogspot.com/2008/02/dynamic-domain-mode-using-nhibernate.html

The idea behind dynamic-component is that you can build your data model by not having a one to one mapping of databse columns with properties. Instead you have only a dictionary property that can contain data from as many properties as you like. This way when you fetch the entity, the dictionary gets the data of all columns configured to belong in there. You can extend the database table's schema to include more columns and that will be reflected to the databse model if you update the mapping file accordingly (manually or though code at application start).

To be honest I do not know you can query such entity using the "attributes" property but if I had to guess I would do an IN statement to it.