stSoftware systems are built from the ground up on a unique multi-layered database structure which allows documents, articles, business rules and all other types of data to be selectively and securely shared across many systems and sites.   

A layered database system is the aggregation of the layers below by selectively placing data and documents in different layers they can be securely shared across the different systems.

Detailed design of a layered database system Multi-Layered DB Application-document