I've come across the "multilevel database" term whilst reading a textbook but it did not provide a proper definition with regards to what it is. Google didn't help either. Can anyone help define this concept to me and how it defers from a standard database implementaion?
Here is a link to pages that describe multilevel databases from Security in Computing By Shari Lawrence Pfleeger at Google Books.
Briefly, a multilevel database provides granular security for data depending on the sensitivity of the data field and clearance of the user for both writing and reading data.
A multilevel database as far as I understand it is a Column based table with different security and view layers. I found this which kinda confirms my thoughts.
The first layer corresponds to a model for a non-protected database. The second layer corresponds to a model for a multilevel database. In this second layer, we propose a list of theorems that must be respected in order to build a secure multilevel database. We also propose a new solution to manage cover stories without using the ambiguous technique of polyinstantiation. The third layer corresponds to a model for a MultiView database, that is, a database that provides at each security level a consistent view of the multilevel database.