How would ning database structure be?

I was just wondering how woudl the database structure of NING would be.

would it be creating seperate tables for each of the site created in it?

or would it be using same table for different module开发者_StackOverflows with a website id column in each table?

if i would need to search about this kind of database stucture? and reference to read about?

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http://raya.codeplex.com/ is an open source Open Social container. Ning is basically the same thing, but with a website id column attached to the root data tables. Look at the SQL from the Raya project.