In Sitefintiy 3.x and 4.0 the database is crated and populated by startup wizard. We use Telerik OpenAccess ORM and it creates all tables and relations between them. All objects are created through API methods. You can create a single installation of a project and then use a database backup to replication it many times.
If your questions are related to Sitefinity 4.0, please use this forum - Sitefinity 4.x: General Discussions
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